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View Full Version : Emirates tail strike


joel payne
09-12-2009, 01:33 PM
Sorry this is a bit long. Just received it on Fri.. Hope it hasn't been posted already.

Article from: The Australian
A small error can have horrendous consequences in aviation. Now the story of Australia's worst near miss can be told

AT 10.31pm, on Friday, March 20 this year, those on duty in the control tower at Melbourne airport witnessed one of the most frightening moments in the history of Australian aviation.

An Emirates Airlines Airbus A340-500 bound for Dubai was roaring down the floodlit runway for take-off when it became clear that something was wrong.

"My members told me the aircraft was not accelerating normally," says Rob Mason, president of the air traffic controller's union, Civil Air. "Then they saw sparks coming from the back of the aircraft as its tail struck the ground as it tried to become airborne."

Those in the tower watched in horror as the struggling Airbus ate up the entire runway and limped into the air, narrowly clearing the airport's perimeter fence. Even after leaving the airport it struggled to gain altitude quickly, flying so low that the control tower could no longer see it.

"The aircraft was lost to sight against the lights of the industrial estate to the south, it was not high enough to be seen," Mason says. Because the jet was flying too low, it also did not initially show up on the tower's radars.

For these few terrifying moments, Emirates Airlines flight 407, carrying 257 passengers and 18 crew, simply vanished from official record, leaving those in the tower to pray that they would not hear an explosion in the suburbs to the south.

"This would have been the worst civil air disaster in Australia's history by a very large margin," aviation expert Ben Sandilands says. "There would have been no survivors from that plane and it would have gone down in (the Melbourne suburb of) Keilor Park, so there would have been deaths on the ground also."

"It was an incredibly serious incident," says Dick Smith, a former head of the Civil Aviation Safety Authority. "They were very lucky that they did not end up in a major accident with a lot of people losing their lives."

SO how did Australia so nearly suffer such a disaster on this clear, mild autumn night? Until then it had been a typical Friday night in Melbourne, with bars and restaurants in full swing. The city's newsrooms were largely empty, with hundreds of journalists and editors partying at the annual media awards night, the Quills, at Crown Casino, oblivious to the huge news story about to unfold on their doorstep.

At Melbourne airport, a 42-year-old Danish pilot was sitting in the cockpit of his Emirates Airbus with his Canadian co-pilot running through their preflight checklist in preparation for their 14 1/2-hour flight to Dubai.

The captain had been flying for 22 years, including almost five years with Emirates and was familiar with Melbourne airport, having flown there at least four times in the previous six months.

He was also familiar with the Airbus, having clocked up 1372 hours on it. But he was tired. He had flown 98.9 hours in the past month, more than Qantas pilots are allowed to fly and barely short of Emirate's monthly limit of 100 hours. The pilot would later claim to have had only 3 1/2 hours sleep in the previous 24 hours because he was "out of whack" despite spending the previous 24 hours resting in Melbourne.

His Canadian first officer was less experienced, having spent 425 hours on the A340-500, but he would be responsible for take-off.

In the cockpit with them were two other Emirates pilots, who would take the second half of the long-haul flight. Behind them the wide-bodied jet was beginning to fill up with passengers. It was the usual assortment of holiday-makers, businesspeople and those for whom Dubai was a transit to other parts of the globe.

One of these was Roman Korobitson, who was travelling with his wife Irena and their two-year-old son to a family reunion in Russia.

At 10.18pm the Airbus pushed back from the gate and taxied to runway 16 for a take-off to the south. The weather was clear and calm for the take-off, which would take the plane over the heavily populated suburb of Keilor and a defence explosives factory in Maribyrnong before turning to the northwest.

The plane was making a reduced-power take-off, which means it was not taking off at full thrust, a common practice among airlines to save fuel, wear and tear and to reduce noise.

At 49 seconds past 10.30pm the Emirates plane began its roll to the south down the illuminated 3657m runway. In the tower, air traffic controllers became alarmed by the plane's slow speed as it neared the take-off point, but cockpit recordings suggest the pilots did not notice anything wrong.

Yet the crew's actions in the next 11 seconds would save the lives of all those on board.

As the plane roared towards the end of the runway the first officer moved his sidestick to rotate, or lift, the plane's front wheel.

When it did not respond, the captain yelled "rotate" again, and the first officer pulled it at a steeper angle.

Three seconds later the front wheel lifted, but the rest of the plane remained glued to the tarmac. At the same time there was a thump as the plane's tail hit the runway, sending showers of sparks into the night.

For six terrifying seconds the Airbus hung suspended, half up, half down, as it gobbled up what remained of the runway. "I knew we couldn't stop," the captain said later. "At that point I knew we just had to go. I thought I was going to die, it was that close."

The tail of the Airbus hit the tarmac twice more and had reached the end of the sealed runway when the captain took over the controls and threw the engines into full thrust using a rapid acceleration procedure known as TOGA (take-off go-around). For another four seconds the plane still refused to fly. It had now run out of sealed runway and was roaring across the grass leading to the airport perimeter fence, hitting its tail twice more on the grass.

At the last possible moment, the whole plane left the ground, clipping a strobe light and flattening a navigation antenna, before clearing the 2.4m airport perimeter fence and thundering low over the roofs of suburban houses.

Inside the cabin, there was confusion but no panic. Some passengers towards the rear of the plane claim to have seen sparks and heard several bumps, but others were oblivious to the near disaster.

"I didn't feel any bump during take-off,' the Russian passenger Korobitson says. "But I was under the impression that it took too long (to take off)."

In the cockpit, having now gained full control of the aircraft, the crew frantically tried to work out what had gone wrong. They slowly climbed to 2100m before they noticed a message saying the plane's tail had been damaged during take-off.

In fact, the strike had caused significant structural damage to the rear bulkhead, which would cause pressurisation problems as the plane gained altitude.

The crew told the Melbourne tower that they would be returning to the airport, and flew out across Port Phillip Bay to dump fuel in order to lighten the plane for an emergency landing.

As they dumped fuel, the pilots reviewed their notes to solve the mystery of the take-off. To their horror, they noticed that the calculations they had used to set the parameters for take-off had inadvertently used a take-off weight that was 100 tonnes below the weight of the aircraft.

The Emirates Airbus contained a laptop that calculated take-off speeds based on the manual input from the pilots of various parameters including take-off weight, temperature, air pressure and wind. The pilot's calculations are then checked by the captain as part of what Emirates says is a four-part process of cross-checks.

Somehow, during the preflight calculations, one of the Emirates pilots -- it's unclear who -- entered the aircraft's weight as being 262 tonnes when in fact it was 362 tonnes.

But a colleague, whose identity is also unclear, failed to pick up the mistake during the cross-checks.

This 100-tonne difference was the equivalent to the aircraft having an extra 20 African elephants on board, or a fully grown adult blue whale.

It meant that the preset take-off speed would never have lifted the plane off the ground had the captain not intervened at the last second to order full thrust.

As the ramifications of their mistake began to sink in, the Emirates crew faced another drama when passengers reported smoke in the cabin. Whether it was smoke or just dust from the substantial damage to the plane's tail is unclear, but the first officer requested an immediate emergency landing despite the fact that the fuel dump was not yet completed.

Six minutes later, with eight emergency vehicles waiting for it, flight 407 touched down with a heavy but safe landing.

After being checked by fire and rescue services, it taxied to the terminal where the passengers emerged, still oblivious to just how close they came to death.

The next day investigators from the Australian Safety Transport Bureau questioned the Emirates pilots at their Melbourne Hotel. The captain said in a later interview that he was on the verge of a breakdown after the incident. "One of my friends almost admitted me to hospital I was so stressed," he said. "If you have a near-death experience your body reacts in a particular way."

After the pilots were interviewed by Australian authorities, they were flown back to Dubai, where they say [B]Emirates handed them prepared letters of resignation. The captain and the first officer have resigned, but not the reserve pilots.

Although the accident received modest media coverage at the time, it was not until three weeks after the accident, that a report in Melbourne's Sunday Herald Sun revealed how serious it was.

In late April the ATSB released its preliminary report, which confirmed the wrong data entry was the likely cause of the accident.

Fearful that its brand would be tarnished, Emirates has responded robustly, placing additional checklist safeguards including using two computers to calculate take-off settings. "The EK407 Melbourne event continues to be treated very seriously with the highest priority at the most senior level in the company," an Emirates spokesman tells Inquirer.

Smith says the key lesson from the Emirates near miss is for pilots not to over-rely on computers. "It is a warning for all pilots to be very careful when they put something in a computer and we have to be careful not to overly rely on computers for calculations in aviation. Emirates is a very good airline with very high standards but it employs human beings and all humans can make errors from time to time."

Sandilands, author of the blog Plane Talking, believes that Emirates, one of the most successful and fastest growing global airlines, has responded well to the incident.

"Did they learn lessons from Melbourne? You bet they have, they realised they could have completely trashed the value of their brand in Australia (if they crashed)."

The ATSB is continuing its investigation into the incident, but says there is no proof that pilot fatigue played a part in the accident. The ATSB says it will release its interim report on the accident at the end of next month.

"It is useless to blame any one airline or flight crew," Smiths says. "Human beings can make errors so double-checks and triple-checks must be done. Unfortunately, it was not done on this occasion."


USMCFLYR
09-12-2009, 05:12 PM
As they dumped fuel, the pilots reviewed their notes to solve the mystery of the take-off. To their horror, they noticed that the calculations they had used to set the parameters for take-off had inadvertently used a take-off weight that was 100 tonnes below the weight of the aircraft.

The Emirates Airbus contained a laptop that calculated take-off speeds based on the manual input from the pilots of various parameters including take-off weight, temperature, air pressure and wind. The pilot's calculations are then checked by the captain as part of what Emirates says is a four-part process of cross-checks.

AHHH! The old "Garbage In = Garbage Out" bites another in the butt.
I'm glad it all worked out in the end of course.

In the P121 world - are reduced thrust take-offs a fairly common practice? The article gives various reasons for the procedure (fuel, wear and tear, and finally niose abatement). In your experience - when you have used reduced thrust take-offs - what was the purpose?
"Human beings can make errors so double-checks and triple-checks must be done. Unfortunately, it was not done on this occasion."
Actually...it sounds like double (at least) and possibly triple checks were used and ALL failed to identify the error.


USMCFLYR

mynameisjim
09-12-2009, 05:31 PM
In the P121 world - are reduced thrust take-offs a fairly common practice? The article gives various reasons for the procedure (fuel, wear and tear, and finally niose abatement). In your experience - when you have used reduced thrust take-offs - what was the purpose?
USMCFLYR

At the airlines I've worked, by default all takeoffs were reduced thrust unless something specific prevents it, like slush or snow, terrain, temperature, etc.

I would that 3/4 or more of part 121 takeoffs are reduced thrust or derated takeoffs.


USMCFLYR
09-12-2009, 05:40 PM
At the airlines I've worked, by default all takeoffs were reduced thrust unless something specific prevents it, like slush or snow, terrain, temperature, etc.

I would that 3/4 or more of part 121 takeoffs are reduced thrust or derated takeoffs.[/quote]

And the primary reason for using reduced take-off thrust is which of the given reasons (fuel, wear/tear, or noise) - or something else?

USMCFLYR

dojetdriver
09-12-2009, 05:55 PM
And the primary reason for using reduced take-off thrust is which of the given reasons (fuel, wear/tear, or noise) - or something else?

USMCFLYR

Usually it's wear and tear. I can't remember the specifics, but at my company, a full thrust or enhanced TO (depending on model) has a pretty significant affect at lowering the life of the engine.

Bloodhound
09-12-2009, 05:56 PM
At XJT, it's primarily wear and tear. I forget the numbers but the engine life is exponentially longer when using reduced thrust. As mentioned, the default t/o is reduced. If we need Full or E T/O (XR model), for runway contamination or short runway, or whatever, we don't hesitate to use it.

dojetdriver
09-12-2009, 05:57 PM
At XJT, it's primarily wear and tear. I forget the numbers but the engine life is exponentially longer when using reduced thrust. As mentioned, the default t/o is reduced. If we need Full or E T/O (XR model), for runway contamination or short runway, or whatever, we don't hesitate to use it.

HA!!!! Beat ya by a minute :D

But like you said, there's been plenty of times (like in Mexico) that if the TOW is even close to the MATOW for a reduced, well, like you said.

KoruPilot
09-13-2009, 02:02 AM
Reduced thrust take off and climb actually uses more fuel, it is strictly for engine life.

On the B777 we used OPT's for take off calc, with a double check from either the opposite side (PM's) OPT or the flight deck lap top. SOP was an independant check, the entry of numbers were spoken by the PM and verified by the PF, and the third pilot (if there was one)on the lap top. On the 744 I make it habit to reference my handy V2 vs weight numbers, compare it to the flight plan and set it initially on the MCP. When the load sheet arrives the numbers are compared as that is where there can be mistakes made (incorrect load sheet data, bad math generally).

Where the pre set on the MCP comes in handy is if a tired piot accidently enters ZFW on the TO weight line on the performance page, pretty much where one can get a 100 ton difference (100 ton sounds like an average long haul fuel). The numbers that the FMC would spit out would then be way off the pre set and the mistake would be obvious, if you get my drift.

Just my way of not doing the same thing as these poor guy's. . . knock wood my friends, smart people have made the same mistake in the past.

III Corps
09-13-2009, 08:13 AM
And the primary reason for using reduced take-off thrust is which of the given reasons (fuel, wear/tear, or noise) - or something else?

USMCFLYR

Heat is the big factor in engine life. Higher heat equals less life. For example, historically the Russians have burned their engines at much higher temps and got more thrust but shorter engine life.

The airlines figured out that if they could get an airplane airborne without using all the thrust, and still meet all FAA requirements then why use the extra thrust. You can use reduced thrust via 'assumed temperature' and/or a 'derate'. In some cases, both. And you wind up rolling down the runway with about 86% N1.

The big thing for me was to check acceleration. With a lighter airplane, your acceleration with reduced thrust should be about the same. So, on the 737 for example, as I remember I was looking for 100kts by 2000ft on takeoff roll.

The military didn't use reduced thrust when I was in but they did use min accel checks. Seemed to me the best option was to use both.

joepilot
09-13-2009, 08:47 AM
Heat is the big factor in engine life. Higher heat equals less life. For example, historically the Russians have burned their engines at much higher temps and got more thrust but shorter engine life.

The airlines figured out that if they could get an airplane airborne without using all the thrust, and still meet all FAA requirements then why use the extra thrust. You can use reduced thrust via 'assumed temperature' and/or a 'derate'. In some cases, both. And you wind up rolling down the runway with about 86% N1.

The big thing for me was to check acceleration. With a lighter airplane, your acceleration with reduced thrust should be about the same. So, on the 737 for example, as I remember I was looking for 100kts by 2000ft on takeoff roll.

The military didn't use reduced thrust when I was in but they did use min accel checks. Seemed to me the best option was to use both.

IIRC, the USAF started using reduced thrust takeoffs on the C-141 fleet in 1974-75. UAL started doing it in the B-727 in 1979.

Joe

KC10 FATboy
09-13-2009, 12:05 PM
This really scares me that this error can have such dire consequences and as such, is crosschecked, triple crosschecked before proceding for takeoff. I'm surprised Emirates doesn't have a procedure to crosscheck the N1 setting during the takeofr roll.

As others have said, reduced power takeoffs are always used, unless maximum power the engines. Indirectly, they are used because they are safer. You are at a higher risk of having an engine failure at a higher thrust setting.

The industry is slowly changing the language surrounding these types of takeoffs. Imagine explaining to a lawyer that you were using a reduced power takeoff and you crashed into an obstacle or hit something on departure. That will go over like a fart in church.

Instead of using the words reduced power, those words are being replaced by the words alternate takeoff power. A full power rated takeoff is becoming a normal power takeoff. A bleeds off full power takeoff is becoming a Maximum Power Takeoff. You gotta love lawyers.

USMCFLYR
09-13-2009, 12:15 PM
This really scares me that this error can have such dire consequences and as such, is crosschecked, triple crosschecked before proceding for takeoff. I'm surprised Emirates doesn't have a procedure to crosscheck the N1 setting during the takeofr roll.

As others have said, reduced power takeoffs are always used, unless maximum power the engines. Indirectly, they are used because they are safer. You are at a higher risk of having an engine failure at a higher thrust setting.

The industry is slowly changing the language surrounding these types of takeoffs. Imagine explaining to a lawyer that you were using a reduced power takeoff and you crashed into an obstacle or hit something on departure. That will go over like a fart in church.

Instead of using the words reduced power, those words are being replaced by the words alternate takeoff power. A full power rated takeoff is becoming a normal power takeoff. A bleeds off full power takeoff is becoming a Maximum Power Takeoff. You gotta love lawyers.

I can not agree that a reduced power takeoff is safer. The advantage of full power that might make a greater difference in a variety of situations vice a small chance of engine failure on take-off would seem to be playing the wroing side of the cards and ORM. I'm sure there are many differences in operating transport category aircraft than any others - but saying that you have a higher risk of engine failure at full thrust would then be a reason to apply this technique across all T/M/S of aircraft.

USMCFLYR

KC10 FATboy
09-13-2009, 12:37 PM
USMCFLYR, I understand that you come from a community that enjoys afterburner takeoffs. Out of simplicity, you are given full mil or afterburner takeoff options.

Even in the military, we use reduced thrust takeoffs. An engine is statistically more likely to experience a failure at maximum power than at a reduced power setting. I don't have any source for that other that what was taught to me by Boeing during my FTUs.

During a reduced power takeoff, the aircraft must meet all of the same requirements as a normal power takeoff. If you lose an engine at Vcef/V1, you are still required to meet all performance requirements with the remaining engine(s) at the reduced thrust. In fact, in every aircraft I've flown with reduced thrust takeoffs, it was taught that you should not apply additional thrust (as it's always available to you) unless for some reason you need it.

I would MUCH rather fly an aircraft that has excess thrust available on takeoff, than an aircraft that needs maximum thrust available in order to get airborne.

USMCFLYR
09-13-2009, 01:03 PM
USMCFLYR, I understand that you come from a community that enjoys afterburner takeoffs. Out of simplicity, you are given full mil or afterburner takeoff options.

Even in the military, we use reduced thrust takeoffs. An engine is statistically more likely to experience a failure at maximum power than at a reduced power setting. I don't have any source for that other that what was taught to me by Boeing during my FTUs.

During a reduced power takeoff, the aircraft must meet all of the same requirements as a normal power takeoff. If you lose an engine at Vcef/V1, you are still required to meet all performance requirements with the remaining engine(s) at the reduced thrust. In fact, in every aircraft I've flown with reduced thrust takeoffs, it was taught that you should not apply additional thrust (as it's always available to you) unless for some reason you need it.

I would MUCH rather fly an aircraft that has excess thrust available on takeoff, than an aircraft that needs maximum thrust available in order to get airborne.

Yes I do....and even though there are times when I would like to make a mil powered take-off (and maybe even a few times when I would make a mil powered take-off) we have to acknowledge that there is a significant safety factor that we are giving up. You've seen it on the video of cat shots even. The aircraft is NOT in A/B while in tension but halfway down the cat shot they engage the A/Bs - for that litttle extra safety margin; even though it is not required. I give it serious thought every time I do a section takeoff since I, as the lead, have pulled a couple of percent out of full A/B.

I understand that it seems to be common practice in the heavy transport community (military and civilian) to use reduced powered take-off per my earlier question and the responses received.

As far as statistical evidence that taking off at reduced thrust on the off chance of a engine failure at higher power vice the known safety margin that a full power provides (across all aircraft types), then I would have to say that IMO it is safer to use a full power takeoff. This would be an interesting safety study/discussion; but like you said - I have spent my entire career being taught that full power takeoffs are safer.

I am not familiar with the reduced pwer takeoff but I do understand what you mean when you say that aircraft must meet all of the performance requirements. I understand that they might JUST make those requirements (the mins), but that doesn't mean that it isn't safer to have a greater margin of making those minumums.

The earlier responses giving wear and tear as a reason for reduced power takeoffs seems right down the alley of the perserving the bottom line - the almighty dollar. In this instance - I believe it is a case of making a decision that a reduced powered takeoff saves gas, saves wear/tear, saves on noise and is GOOD ENOUGH to meet the safety requirements.

USMCFLYR

navigatro
09-13-2009, 01:35 PM
USMC,

"safer" does not mean the same thing in all situations, and is subjective.

It is a statistical FACT that a reduced power takeoff (turbofan engines) lowers the risk of engine failure. In that context, it is "safer."

Of course obstacle clearance and other things are factored in the equation to determine how much to reduce the takeoff thrust setting.

Also, at very light weight and aft CG configurations, 4-engine aircraft may become (temporarily) uncontrollable with an outboard engine failure during the takeoff roll. Hence another reason to use reduced power takeoffs.

In the fighter world, AB takeoffs are indeed "safer".

KC10 FATboy
09-13-2009, 01:41 PM
You are comparing Naval Aviation catapult takeoffs with normal aviation takeoffs. Apples and oranges.

An engine is more likely to fail at higher power settings. This is a fact, and makes sense. The more power you ask from the engine, the more stress and heat damage you cause. If you are at a higher risk for using higher power settings, then why would you use them when you didn't need to?

This just isn't for heavies. The business jets, commuters, small airliners, and big jets use it.

USMCFLYR
09-13-2009, 01:51 PM
USMC,

"safer" does not mean the same thing in all situations, and is subjective.

It is a statistical FACT that a reduced power takeoff (turbofan engines) lowers the risk of engine failure. In that context, it is "safer."

Of course obstacle clearance and other things are factored in the equation to determine how much to reduce the takeoff thrust setting.

Also, at very light weight and aft CG configurations, 4-engine aircraft may become (temporarily) uncontrollable with an outboard engine failure during the takeoff roll. Hence another reason to use reduced power takeoffs.

In the fighter world, AB takeoffs are indeed "safer".

Absolutely - which is why I am trying to understand the difference in what seem to be a heavy transport category aircraft procedure and one that fits across all type/model and series.

I have only flown light GA aircraft and the T-34C through Hornet in the military and I had never been introduced to reduced powered takeoffs. I would think that if it was safer to make reduced powered takeoffs because of high probability of engine failure vice the safety margin given a full power takeoff then it would seem that I might have come up against this technique sooner.

So...this seems to be a difference, so far at least since no one else from a different community has chimed in, to be a P121/heavy transport procedure.

Some of you seem to think that I am arguing against reduced powered takeoffs. to the contrary - having not flown P121 or heavy transport I don't know if it is better or worse. Just as I always do when sitting in the back I trust that the crews and procedures they are using have been vetted and found safe to operate.
I disagree with the contention that the small chance of an engine failure overrides the many safety margins that a full power takeoff gives you.
It gives me decreases takeoff distance, increased obsticle clearance, a steeper climb angle and getting me away from the ground quicker, and more thrust/speed should I have an emergency - which at least in my airplane and most others I have flown is a good thing.

Finally - though I have not seen it myself and even KC said that it was what was taught but has not seen the evidence - even if it was statistically a greater chance, my own Operational Risk Management says that I'll take the goods of a full power takeoff over the reduced power takeoff and the very small chance of engine failure due to a high power setting.

I wonder if given the oportunity - not goverened by your companies operating limitations (which are probably based on monetary savings or noise restrictions) - how many would CHOOSE a reduced powered takeoff?

Interesting discussion.

USMCFLYR

Btw - does anyone have any opinions on the failure of the double/triple checks of the numbers here? I've seen one post address this and that members procedure for backing up the numbers. What are some other techniques/procedures for ensuring good information in/good information out?

USMCFLYR
09-13-2009, 01:59 PM
You are comparing Naval Aviation catapult takeoffs with normal aviation takeoffs. Apples and oranges.

An engine is more likely to fail at higher power settings. This is a fact, and makes sense. The more power you ask from the engine, the more stress and heat damage you cause. If you are at a higher risk for using higher power settings, then why would you use them when you didn't need to?

This just isn't for heavies. The business jets, commuters, small airliners, and big jets use it.

No KC - I was not comparing the takeoffs - rather the idea that I want every bit of thrust coming out of my engines that I can get. So far - this has been my thought process.

As for the second bolded comment - because just meeting the mins if I can have a higher safety margin is safer IMO.

I guess the problem I'm having in this discussion is the safety factor. I will have to do some research myself but I'd bet a beer that increase SAFETY is on down the list when the reasons for reduced power takeoffs are considered.

Navigatro
Also, at very light weight and aft CG configurations, 4-engine aircraft may become (temporarily) uncontrollable with an outboard engine failure during the takeoff roll. Hence another reason to use reduced power takeoffs.
This is a good point. I'm sure there are specific circumstances. Question for those flying the heavies - especially in the circumstances above - if on takeoff and let's say 500' - would the first procedure not be to go to full power on the remaining engines?

USMCFLYR

I'm sure it is used in all those situations that you mention.

forumname
09-13-2009, 02:11 PM
This really scares me that this error can have such dire consequences and as such, is crosschecked, triple crosschecked before proceding for takeoff. I'm surprised Emirates doesn't have a procedure to crosscheck the N1 setting during the takeofr roll.


If I remember correctly, besides a long duty day/fatigue, it was failure to crosscheck, or verify numbers that resulted in the ACMI 747 crash in YHZ a few years back.

I'd have to go through and reread the information, but I thought that's what main factors were.

jungle
09-13-2009, 02:12 PM
Most military aircraft in the fighter/attack category have a fairly narrow operating weight range and would not benefit much from reduced thrust takeoffs. On some large jets the takeoff weight range can be up to around 50% of max gross. These jets also may keep an engine on the wing(no major overhaul) longer than a fighter's lifespan, so economy is an important and even vital requirement.
Reduced power takeoffs are not used if runway/aircraft conditions are critical. Safety is always the primary issue.

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"The general approach adopted by Boeing is the calculation of a Corrected Runway Length whichgeneralizes WAT-effects (Weight-Altitude-Temperature).The corrected Engine Inoperative Takeoff Distance is the actual runway length corrected for specificconditions such as the presence and use of a clearway, the effects of runway slope, wind, anti-ice,engine bleed, MEL-items, line-up distance, etc. The corrected Engine Inoperative Accelerate-Stop Distance is the actual runway length corrected forthe presence and use of a stopway, the effects of runway slope, wind, anti-ice, engine bleed, MEL-items, line-up distance, etc.The actual takeoff weight determines the takeoff safety speed V2 and the rotation speed VR isdetermined from V2 as a function of altitude and temperature.Whenever field length limited the maximum performance is obtained for the balanced takeoffwhere the corrected Engine Inoperative Takeoff Distance is equal to the corrected EngineInoperative Accelerate-Stop Distance, resulting in a balanced field length."
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Appendix 2: Takeoff Accidents resulting from inadequate performanceMK Airlines Limited Boeing 747-244SFOn 14 October 2004, an MK Airlines Limited Boeing 747-244SF was being operated as a non-scheduled international cargo flight from Halifax, Nova Scotia, to Zaragoza, Spain. At about 0654coordinated universal time, MK Airlines Limited Flight 1602 attempted to take off from Runway 24 atthe Halifax International Airport. The aircraft overshot the end of the runway for a distance of825 feet, became airborne for 325 feet and then struck an earthen berm. The aircraft's tail sectionbroke away from the fuselage, and the aircraft remained in the air for another 1200 feet before itstruck terrain and burst into flames. The aircraft was destroyed by impact forces and a severe post-crash fire. All seven crew members suffered fatal injuries.In this accident, the flight crew's take-off performance calculations resulted in an error thatremained undetected until the aircraft reached a point where the crew's response was too late toavert the accident.Source: Transportation Safety Board of Canada, Accident Report A04H0004Other Accidents; a review by the Transportation Safety Board of CanadaA review of large (above 5700 kg), turbine-powered aircraft accident and incident data has shownthat there have been at least 12 major occurrences where take-off performance was significantlydifferent from scheduled performance. Four of the aircraft involved were destroyed and there were297 fatalities.Several of these occurrences involved flight crews that attempted a take-off using incorrectperformance data, and then did not recognize the inadequate take-off performance of the aircraft.There were other accidents where the take-off performance has been inadequate because ofmechanical failures, incorrect aircraft configuration or incorrect instrument indications. Theseoccurrences were not isolated to any particular aircraft type, commercial operation or geographicarea.Underlying most of these occurrences were one or both of the following safety issues: The failure or absence of procedural defences to detect an error in the take-off performancedata; and The failure of the crews to recognize abnormal performance once the take-off hadcommenced. The following are some representative accidents taken from the data: On 12 March 2003, a Boeing 747-412 suffered a tail strike on take-off in Auckland, NewZealand, and became airborne just above the stall speed (New Zealand Investigation03 003). The aft pressure bulkhead was severely damaged, but the crew managed to landsafely. The cause of the tail strike was a result of the flight crew entering a take-off weight
--------------------------------------------------------------------------------
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100 tonnes less than the actual weight into the flight management system, resulting in lowtake-off speeds being generated. There was no crew cross-checking of the speeds. On 11 March 2003, a Boeing 747-300 in Johannesburg had a tail strike on take-off (NTSBreport DCA03WA031 refers). The flight engineer had entered the zero fuel weight of203 580 kg instead of the take-off weight of 324 456 kg into the hand-held performancecomputer, and then transferred the incorrect computed take-off speeds onto the take-offcards. On 14 June 2002, an Airbus A330 had a tail strike on take-off in Frankfurt, Germany, becauseincorrect take-off data were entered into the flight management system (TSB reportA02F0069 refers). The tail strike was undetected by the flight crew, but they were notifiedby air traffic services during the climb-out. The aircraft sustained substantial structuraldamage to the underside of the tail. On 28 December 2001, a B747-200 cargo aircraft had a tail strike on take-off in Anchorage,Alaska, and sustained substantial damage (NTSB report ANC02LA008 refers). The crew didnot account for the weight of the additional fuel (about 45 360 kg) taken on board inAnchorage, and inadvertently used the same performance cards that were used for theprevious landing. The crew members were unaware that the tail had struck the runway untilafter arrival at their destination. On 13 January 1982, a Boeing 737-222 was on a scheduled flight from Washington, DC, toFort Lauderdale, Florida. During take-off, the EPRs were set for 2.04, and on the take-off run,anomalous engine instrument readings were noted; the captain elected to continue thetake-off. Approximately 2000 feet and 15 seconds past the normal take-off point, the aircraftbecame airborne. The aircraft initially climbed, but failed to accelerate. The stall warningstick shaker activated shortly after take-off and continued until the aircraft settled, hit the14th Street Bridge and several vehicles, then plunged into the frozen Potomac River. Theinvestigation revealed that the engine inlet pressure probes became blocked with ice,resulting in high EPR indications. Of the 79 persons on board, 74 perished, and there werefour ground fatalities. From at least as far back as 1972, there have been safety recommendations and initiatives to ensurethat crews have a reliable on-board method of detecting abnormal take-off performance,particularly in situations where performance is less than required or expected. Unfortunately, thereis still not a reliable in-cockpit system available for crews to detect and react to abnormal take-offperformance in a timely manner.Source: Transportation Safety Board of Canada

USMCFLYR
09-13-2009, 02:18 PM
If I remember correctly, besides a long duty day/fatigue, it was failure to crosscheck, or verify numbers that resulted in the ACMI 747 crash in YHZ a few years back.

I'd have to go through and reread the information, but I thought that's what main factors were.

But didn't the ATSB determine that fatigue was not a factor in this mishap? I remember it being mentioned that the pilot had not had much sleep the night before - though he had a 24 hour rest before that. The other two pilots had no fatigue factors. I would think that this was a failure of procedures; not necessarily fatigue. Who can **really** say in the end I guess.

USMCFLYR

forumname
09-13-2009, 02:28 PM
To tell you the truth, I'd have to go back a reread it. You're probably correct, I thought I remember it being in there though.

But didn't the ATSB determine that fatigue was not a factor in this mishap?

I wouldn't doubt it. But how many times have we seen an investigating agency discount it, but we all knew better?

I remember it being mentioned that the pilot had not had much sleep the night before - though he had a 24 hour rest before that.

True, and maybe it's happened to you, don't know. But just because somebody has had a 24 hour rest period doesn't ensure they are well rested to fly. Especially if there were multiple body clock swaps in a relatively short amount of time. As well as the sleep pattern never being able to be synced to comply with the duty period. I know it's happened to me, one just recently.

The other two pilots had no fatigue factors. I would think that this was a failure of procedures; not necessarily fatigue.

Edited, made a typing mistake;

Again, I'd have to go back and reread the report. But to repeat what I said, we've all heard of cases where fatigue wasn't listed as factor by the investigative body.

Who can **really** say in the end I guess.

USMCFLYR

True, glad that a failure to verify/cross check number didn't have a fatal result.

KC10 FATboy
09-13-2009, 02:36 PM
I wouldn't let an article be the source I use to quote what the ATSB determined. With that being said, we have no idea what the procedures in place were at that time and if they were followed. We also don't know if fatigue was a casual factor. Perhaps the pilot said so in order to provide him some cover. As I mentioned earlier, does Emirates have any procedural checks to ensure the thrust set for takeoff is adequate? Of course, this probably wouldn't have changed anything because they would have just ensured the wrong N1 setting was set for takeoff. The problem seems to have come setting the wrong N1 because the weight was incorrect.

navigatro
09-13-2009, 02:46 PM
[

This is a good point. I'm sure there are specific circumstances. Question for those flying the heavies - especially in the circumstances above - if on takeoff and let's say 500' - would the first procedure not be to go to full power on the remaining engines?

USMCFLYR

[/quote]

No, you do not go to full power on the remaining engines. The reduced power settings factor in the loss of an engine when calculating obstacle clearance.

USMCFLYR
09-13-2009, 02:53 PM
No, you do not go to full power on the remaining engines. The reduced power settings factor in the loss of an engine when calculating obstacle clearance.

Interesting...thanks for the clarification.
Definitely different from my community.

USMCFLYR

joepilot
09-13-2009, 04:29 PM
Does anybody know what the maximum reduction normally allowed for takeoff is? I have seen 15% reductions allowed (note: not 15% N1, 15% of actual thrust). Are other aircraft allowed a greater reduction?

Joe

jungle
09-13-2009, 04:42 PM
Does anybody know what the maximum reduction normally allowed for takeoff is? I have seen 15% reductions allowed (note: not 15% N1, 15% of actual thrust). Are other aircraft allowed a greater reduction?

Joe

Boeing goes TO, TO1, TO2- representing full, -5%, and -15%, in addition each of these ratings may be assumed off for temp up to 53 degrees C giving no more than a 25% reduction at most. The FMS will limit thrust reduction.

A rated thrust( TO, TO1, TO2) implies that you will not increase thrust in event of an engine failure, whereas an assumed thrust gives you that option.

Bottom line is the crew is responsible for input of the correct weight and other takeoff data, a critical step that all crewmembers must verify.

III Corps
09-13-2009, 04:46 PM
Here is a good primer on derates and reduced thrust.
Assumed Temperature Thrust Reduction (http://www.b737.org.uk/assumedtemp.htm)

On one of the airbus sites a PPT says the -320 can do a reduction of up to 25% of available thrust.

USMCFLYR
09-13-2009, 05:17 PM
Here is a good primer on derates and reduced thrust.
Assumed Temperature Thrust Reduction (http://www.b737.org.uk/assumedtemp.htm)

On one of the airbus sites a PPT says the -320 can do a reduction of up to 25% of available thrust.

III Corps -

Thanks for the reference. Very informative.

USMCFLYR

flyboyPH
09-13-2009, 05:25 PM
We do Reduced thrust (Flex) TO anytime we can. The lowest N1 setting we can use is 85%

Airhoss
09-27-2009, 08:34 PM
This is all very interesting but you can't fly 98.2 hours international or otherwise in a month and NOT be chronically fatigued. PERIOD.

Great Cornholio
10-01-2009, 08:39 PM
[

No, you do not go to full power on the remaining engines. The reduced power settings factor in the loss of an engine when calculating obstacle clearance.

What kind of a/c are we talking about here? I have flown the BE 1900, BA 4100, and EMB 145...So nothing close to heavy, but this is new to me. The 1900 didn't use reduced power takeoffs, but both the BA 4100 and EMB 145 we use reduced takeoffs unless we need full power. On both of those planes if we lose an engine the first thing we do is go to full power on the good engine....(the EMB 145 even has a logic that will automatically put the good engine to full power if one is lost during reduced takeoff thrust mode) Our memory items include moving the thrust lever to the full power stop as a backup to the auto logic to make sure the good engine goes to full power.

Oh and for the F18 guy...the amount we reduce thrust by is right around 10% of the thrust so that means we takeoff at 90% thrust (lbs not N1 setting). From what I've noticed it doesn't seem to make a big difference if you reduce or not for the same weight....a bigger difference is felt compared to being light vs heavy.

The Dominican
10-01-2009, 10:05 PM
What kind of a/c are we talking about here? I have flown the BE 1900, BA 4100, and EMB 145...So nothing close to heavy, but this is new to me. The 1900 didn't use reduced power takeoffs, but both the BA 4100 and EMB 145 we use reduced takeoffs unless we need full power. On both of those planes if we lose an engine the first thing we do is go to full power on the good engine....(the EMB 145 even has a logic that will automatically put the good engine to full power if one is lost during reduced takeoff thrust mode) Our memory items include moving the thrust lever to the full power stop as a backup to the auto logic to make sure the good engine goes to full power.

Oh and for the F18 guy...the amount we reduce thrust by is right around 10% of the thrust so that means we takeoff at 90% thrust (lbs not N1 setting). From what I've noticed it doesn't seem to make a big difference if you reduce or not for the same weight....a bigger difference is felt compared to being light vs heavy.

Depends on the A/C, the information that Jungle posted is correct and you can see on the 767 up to 25% reduced thrust for T/O as a max reduction, the only thing you have to be a little careful with when you have a long aluminum tube behind you is not to venture beyond the 3 degrees/ second rate of rotation since the likelihood of a tail strike at reduced thrust is little higher.

There is also the controllability issue with wing mounted engines because as you apply the remaining thrust, you will have to apply a healthy amount of rudder to compensate, the procedure doesn't call to apply full thrust. It is just one of those handful of things that is a little different when you are flying the heavy Iron

The Dominican
10-01-2009, 10:38 PM
I wonder if given the oportunity - not goverened by your companies operating limitations (which are probably based on monetary savings or noise restrictions) - how many would CHOOSE a reduced powered takeoff?

Interesting discussion.

USMCFLYR


Max thrust at light weights in the 767 and you are going to be climbing at more than 5,000 fpm with a deck angle higher than 20 degrees in some of these departures that call for low altitude level off you are going to be exposing the passengers to unnecessary G's (I understand G's is a source of entertainment in your neck of the woods) manhandling the inertia that is created by a couple of hundred tonnes can give the folks an uncomfortable ride.

Besides it is not a company imposed limitation in the sense that you are obligated to use reduced thrust, it is always at the pilot's discretion and you are not going to hear a peep if you decide to use max thrust in a particular T/O. But then again, I fly in a very "captain discretion" oriented company

Great Cornholio
10-02-2009, 09:03 AM
Depends on the A/C, the information that Jungle posted is correct and you can see on the 767 up to 25% reduced thrust for T/O as a max reduction, the only thing you have to be a little careful with when you have a long aluminum tube behind you is not to venture beyond the 3 degrees/ second rate of rotation since the likelihood of a tail strike at reduced thrust is little higher.

There is also the controllability issue with wing mounted engines because as you apply the remaining thrust, you will have to apply a healthy amount of rudder to compensate, the procedure doesn't call to apply full thrust. It is just one of those handful of things that is a little different when you are flying the heavy Iron

Thanks. I was wondering if he was talking military transport or airline heavy. I had no idea that you guys didn't push the thrust up on the good engine....but to be honest never really thought about it. The wing mounted engine and needing more rudder makes sense, but we did it in the turboprop and sometimes it would get kinda sporty in the sim. In my opinion the 145 is underpowered (EP especially) and if we didn't throw to good engine up to full power we would probably fall out of the sky. I hope to be flying heavy iron soon, but with the way things are these days it looks like I'm going to get to live the dream one nightmare at a time for a little while longer here in the regional level. On a side note is your "heavy captain discresion" company still hiring expat guys?

CloudSailor
10-02-2009, 09:31 AM
Cornholio,

Dominican flies the 767 for ANA, and he's a great guy to get in touch with if you go that route.

You can check out the contract via www.crewresourcesworldwide.com (http://www.crewresourcesworldwide.com) or through PARC.

Good luck.

Sniper
10-02-2009, 09:28 PM
Max thrust at light weights in the 767 and you are going to be climbing at more than 5,000 fpm with a deck angle higher than 20 degrees . . .

I would say that this is likely something that most pilots with non-heavy experience don't immediately think about, the HUGE difference, not only pure weight wise, but % wise too, between a 'light' and a 'heavy' t/o in a very large aircraft.

Think a 747 out of JFK. Could be just going empty to Boston, or could be going to Seoul full of 14+ hours of fuel and passengers/cargo. We're talking a difference of over 300,000 lbs here b/t these two t/o scenarios (more than 125% of the entire Emirates t/o weight miscalculation), a difference of almost 40%, weight wise, b/t min and max scenarios. The engines obviously have to have the thrust to do an 800K lb t/o, so, if you give them full power but 40% less weight to pull into the air to BOS (think of an 18K lb ERJ @ max thrust, 'Cornholio'), you've got a serious amount of power, considering the 74 will usually reduce T/O thrust out of JFK @ MTOW.

The centerline thrust difference is one thing with heavies v/s RJ's and military fighters, but the huge weight range that a 'heavy' operates in is a easy concept to grasp once pointed out, but perhaps not immediately obvious without personal experience.

Great Cornholio
10-03-2009, 12:46 AM
I would say that this is likely something that most pilots with non-heavy experience don't immediately think about, the HUGE difference, not only pure weight wise, but % wise too, between a 'light' and a 'heavy' t/o in a very large aircraft.

Think a 747 out of JFK. Could be just going empty to Boston, or could be going to Seoul full of 14+ hours of fuel and passengers/cargo. We're talking a difference of over 300,000 lbs here b/t these two t/o scenarios (more than 125% of the entire Emirates t/o weight miscalculation), a difference of almost 40%, weight wise, b/t min and max scenarios. The engines obviously have to have the thrust to do an 800K lb t/o, so, if you give them full power but 40% less weight to pull into the air to BOS (think of an 18K lb ERJ @ max thrust, 'Cornholio'), you've got a serious amount of power, considering the 74 will usually reduce T/O thrust out of JFK @ MTOW.

The centerline thrust difference is one thing with heavies v/s RJ's and military fighters, but the huge weight range that a 'heavy' operates in is a easy concept to grasp once pointed out, but perhaps not immediately obvious without personal experience.

This makes sense. I know that I notice a huge difference in how the ERJ acts when heavy compared to when light...and we are talking of a diff of only about 15,000 to 20,000 ish lbs....or just shy of 50% weight. Although we go to max thrust on the good engine regardless of our weight. While I've thought a few times about how heavys have many times my MAGTOW in fuel alone I've never thought about weight in the V1 cut. In everything I've ever flown if you lose an engine you have to give the good engine all its got in order to miss the trees at the end...and some times all its got isn't good enough and you will hit the trees anyways (light piston twin). I'd say if there is one thing about RJ's that makes me mad (other than pay etc) its the fact that we are typically under powered. There is no reason we shouldn't be able to climb and cruise as fast as mainline jets. I guess on the plus side for me it seems V1 cuts will get easier or simplier as I go on. Turboprops to RJ's was a nice change and now it seems like I can take the little extra rudder out when we "goose the good engine" when I get to the big iron.

The Dominican
10-03-2009, 09:27 PM
I would say that this is likely something that most pilots with non-heavy experience don't immediately think about, the HUGE difference, not only pure weight wise, but % wise too, between a 'light' and a 'heavy' t/o in a very large aircraft.
.

And remember that reduced thrust can only be accomplished when you have performance to spare, when you are close to your MTOW the numbers won't allow it.

On a personnal note, I like the fact that now in many cases I have performance to spare :D

4everFO
10-11-2009, 11:43 AM
I fly the 747-400 and during a max derate and a high assumed temp scenario (D-TO2 58 degrees) with an engine out, it climbs like a dog even when light. My company allows discretion in increasing thrust on the remaining three. You will make the climb requirements, at a much slower rate, with the remaining 3 at the original thrust settings. On PCs I leave the original thrust setting because by the time I am airborne I should have already sorted out the amount of rudder required to keep her straight and more thrust would obviously change that.

I flew the EMB 145 series and if I remember correctly, the reason that the FADEC added power after sensing a engine failure was due to the fact that when reduced it was possible to still meet the 2 engine climb performance but needed the "reserve" thrust to make the SE requirements. It is certified that way....when the reserve power function was MEL'd, there was a weight penalty (may be confusing with the CRJ).

FO

SabreDriver
11-02-2009, 02:04 PM
[

No, you do not go to full power on the remaining engines. The reduced power settings factor in the loss of an engine when calculating obstacle clearance.

Depends on who your performance chart data vendor is. I would most certianly use MCT at the loss of one of my engines on takeoff, depending on the takeoff weight. If the jet is maxedout at 830k, you are gonna need every bit, just get busy putting it up. If it is at 450k, maybe not so much... Second segment climb data is predicated on MCT on the remaining engines. Besides, you need every ounce of thrust to get the jet sped up and cleaned up as quickly as possible. If you leave the thrust reduced, you are off the charts and now a test pilot, let us know how it comes out. For me, I don't want to be on the 6 O'clock news that bad.

Reduced thrust (also called FLEX) takeoffs are only to save maintenance money. For you, USMCFLYR, think of as intentionally turing most every takeoff into a critical field length takeoff, depending on the thrust reduction taken. If you end up rejecting the takeoff at V1, minus a few knots, you had better be on your game that day, you are about to use up a bunch of brakes and tires. I can't count the number of heavy takeoffs that I have done where when the PNF said V1 and I looked at the runway remaining thinking, there is no way we would be able to stop. So far, have not had to test it. Thank God :cool:

UAL T38 Phlyer
11-03-2009, 04:21 AM
USMC:

The reduced-thrust concept was new to me, too, upon training for my first airline job. I was told:

The last 10% of an engine's rated-thrust is where 90% of the engine failures occur.

As a guy with an engineering background, I can buy that, from a fatigue, manufacturing tolerance, or materials variance perspective.

Thrust is not linear with RPM; it is exponential. 90% rpm is roughly 50-60% of total thrust available at 100% rpm. Small reductions in rpm are big reductions in thrust, and the probability of engine failure is directly proportional to the amount of thrust coming out of the tailpipe. One instructor told me a 2% rpm reduction lowers the probability of failure by 50%.

The numbers must bear it out...I don't think the FAA would approve it otherwise.

Given the same background as you, I was surprised to find that heavy-weight takeoffs in the 747 (sim) were easier at reduced thrust than lightweight, with any power setting.:confused: Why?

The sim instructor almost always fails an outboard engine, giving you the maximum assymetric moment-arm. Higher weights mean faster rotation and V1/V2 speeds.

And the faster you are going, the more effective the vertical fin and rudder. Reduced thrust lowers the assymetry.;)

USMCFLYR
11-03-2009, 04:55 AM
USMC:

The reduced-thrust concept was new to me, too, upon training for my first airline job. I was told:

The last 10% of an engine's rated-thrust is where 90% of the engine failures occur.

As a guy with an engineering background, I can buy that, from a fatigue, manufacturing tolerance, or materials variance perspective.

Thrust is not linear with RPM; it is exponential. 90% rpm is roughly 50-60% of total thrust available at 100% rpm. Small reductions in rpm are big reductions in thrust, and the probability of engine failure is directly proportional to the amount of thrust coming out of the tailpipe. One instructor told me a 2% rpm reduction lowers the probability of failure by 50%.

The numbers must bear it out...I don't think the FAA would approve it otherwise.

Given the same background as you, I was surprised to find that heavy-weight takeoffs in the 747 (sim) were easier at reduced thrust than lightweight, with any power setting.:confused: Why?

The sim instructor almost always fails an outboard engine, giving you the maximum assymetric moment-arm. Higher weights mean faster rotation and V1/V2 speeds.

And the faster you are going, the more effective the vertical fin and rudder. Reduced thrust lowers the assymetry.;)

Thanks to everyone for your explanations of the Reduced Takeoff Thrust (FLEX). Phlyer - I threw that around the ready room and got the same reaction out of the military only trained pilots, but the reservists explained it in somewhat the same manner as you.

USMCFLYR

pilotgolfer
11-03-2009, 06:40 AM
I haven't read all of the previous posts, so if this is a repeat, I apologize.

Engines failures are very rare nowadays but something like over 95 % of engine failures occur during max power takeoffs. When we did TRT takeoffs on the C-141, it always felt like the plane was gonna rattle to pieces!

crazyjaydawg
11-03-2009, 10:38 AM
Having worked in PE at NWA for a couple years I can agree with pretty much everything being said. Using De-rates/flex/optimized or whatever you want to call it, you can almost double the time between overhaul while reducing your chance at an engine failure. In fact the TBOs have gotten so high that the fan blades start to deteriorate and we need to come up with fan blade deterioration mode to go along with the drates on both the 57s and 320s.

Even on the 9osaur we can do overspeed which is by admission a poor mans de-rate.

698jet
11-07-2009, 12:54 PM
on the 777ER we always use reduced power takeoffs. i think most airlines use it. we have a boeing laptop that we put in all the numbers and it is checked by my co-pilot and myself. we get the number of paxs and load form a load master and it works out great. but I can see if you dont check all the numbers it can get you in a bind fast.

rickair7777
11-07-2009, 07:18 PM
On a turbine engine, you would expect most failures to occur at higher power settings. As stated, there is a very large percentage power increase in the last few percentage points of RPM.

A piston engine is different though. The typical mechanical failure (other than those due to loss of oil) occurs when REDUCING power after a high power run. The crankshaft, rods, and other parts "unwind", which encourages any weak components to fail. This why it's a good idea not reduce power in an piston ASEL until you have enough altitude to glide to a good landing site.

KoruPilot
11-08-2009, 12:18 AM
First, great discussion.

Second, someone mentioned that second segment is based, always, on max toga power. Not on the 744 or the 777 as far as I understand. On the 744 the charts (we still use charts) tell you if you are climb/runway/obstacle restricted and your max weight is restricted by, well the most restrictive restriction (sorry it's late). On the 777 the OPT tells you the same without pointing it out (as is noticible on the charts). So, if you are 395 ton or 295 ton it doesn't matter. Don't get me wrong, if I lost an engine I'd hit the toga buttons again. I tried it in the 777 sim as the instructor wanted us to do it the hard way, no toga button, and it climbed like a pig. I imagine an airplane with tired engines would be worse. So, stupid yes, but I think not actually incorrect.

JetJocF14
11-19-2009, 04:28 PM
Not related to your tailstrike but myself and my co-pilot had to D/H from Dubai to Osaka, Japan earlier this month in first class on one of your 777. You guys run a class act...............