Asiana 777 Crash at SFO
07-12-2013, 12:20 PM
#511
Gets Weekends Off
Joined APC: Sep 2008
Position: seated beer curl
Posts: 406
Originally Posted by F15andMD11
Yea, I understand what you're saying about rusty but...not impressed.
For a ferry flt sure. But a revenue flt no! I've watched guys shut-off the automation. "Look what a good pilot I am." What do you think the media's and the company's reaction will be when they learn you have the automation off and you were, God forbid, involved in a mishap. Especially those with safety redundancies like auto throttles. You'd be hung out to dry. Just wait until we learn Asiana had AT off. The pilots will be even more roasted. IMO once you're in the big leagues flying heavy metal those "look at me" days are over!! For your passengers sake!! Sorry, I'll get off my soap box. Just my safety training. 
For a ferry flt sure. But a revenue flt no! I've watched guys shut-off the automation. "Look what a good pilot I am." What do you think the media's and the company's reaction will be when they learn you have the automation off and you were, God forbid, involved in a mishap. Especially those with safety redundancies like auto throttles. You'd be hung out to dry. Just wait until we learn Asiana had AT off. The pilots will be even more roasted. IMO once you're in the big leagues flying heavy metal those "look at me" days are over!! For your passengers sake!! Sorry, I'll get off my soap box. Just my safety training. 
07-12-2013, 12:45 PM
#513
Organizational Learning
Joined APC: Nov 2005
Position: Directly behind the combiner
Posts: 4,948
Originally Posted by F15andMD11
Originally Posted by Radials Rule
... I use manual thrust for hand flown approaches and landings whenever I can. Otherwise, I feel like I'm rusting and that I would subconsciously pay less attention to airspeed in my scan.
For a ferry flt sure. But a revenue flt no! I've watched guys shut-off the automation. "Look what a good pilot I am." What do you think the media's and the company's reaction will be when they learn you have the automation off and you were, God forbid, involved in a mishap. Especially those with safety redundancies like auto throttles. You'd be hung out to dry. Just wait until we learn Asiana had AT off. The pilots will be even more roasted. IMO once you're in the big leagues flying heavy metal those "look at me" days are over!! For your passengers sake!! Sorry, I'll get off my soap box. Just my safety training.
Originally Posted by F15andMD11
Originally Posted by contrails
It's not about "look at me I can fly." I'm not sure where you get that, but it's not from any of the pilots I've ever sat next to in 121 so far.
Valid point, of course you shut-off AP when required. I'm just thinking about the AT I guess.
An 8-year-old can keep the steering bars centered. Airspeed management requires a scan.
.
07-12-2013, 01:54 PM
#514
Prime Minister/Moderator
Joined APC: Jan 2006
Position: Engines Turn Or People Swim
Posts: 39,293
Originally Posted by galaxy flyer
Rickair7777,
It's already happened--Colgan 3407
GF
It's already happened--Colgan 3407
GF
But at least the Colgan crew was IMC...they look not quite as bad compared to this.
07-12-2013, 01:56 PM
#515
Line Holder
Joined APC: Jan 2008
Position: F-16 & 737 gear actuator
Posts: 95
07-12-2013, 02:12 PM
#517
Gets Weekends Off
Joined APC: Jul 2005
Posts: 249
The 777 series is interesting in aircraft design in that Boeing had to account for new factors for deriving VREF MIN. VREF MIN typically is 1.23VS1g.
As the 777 evolved through the 200ER to the 200LR and 200F versions, Boeing had to increase VREF MIN above the standard due to a significant increase in thrust (depending on engine type) but the same vertical stabilizer and rudder. This is for landing gross weights less than approximately 480,000lb.
In this case VMCL could exceed VSS. Boeing ensures that VREF MIN is equal to or greater than 1.23VS1g, or VMCL, or VLOC + 17kts.
VMCL and VLOC don't change with weight, as 1.23VS1g does. Looking at Flaps 30 VREF, for the -200LR/F variants, the VREF speed is 137 kts at approx 480,000 lb and below, meaning that the VREF MIN is determined from VMCL or VLOC, not 1.23VS1g.
For the Asiana 214 777-200ER(PW), the VREF is still based on 1.23VS1g(due to the VREF decreasing with weight).
It is not clear if 137kt was VREF speed or VREF+5. From the way it was reported, I am assuming 137kt was VREF+5, and VREF then was 132kt.
If VREF = 132, then VS1g = 107(divide 132 by 1.23).
Stick Shaker speed, VSS, is 3-5% above VS1g. In this case then VSS = 110-112 kt.
The top of the amber bar, minimum maneuver speed, is derived directly from the stick shaker speed, it is 1.14VSS.
Then 1.14VSS = 126 kts.
Using this data against the NTSB data, they started to advance power 7 seconds prior to impact, (at 8 seconds speed was 112 kts), right at stick shaker speed. The lowest indicated speed was reported to be 106 kts, at stall speed.
The AIRSPEED LOW EICAS msg should have displayed at approximately 23 seconds from impact.
As the 777 evolved through the 200ER to the 200LR and 200F versions, Boeing had to increase VREF MIN above the standard due to a significant increase in thrust (depending on engine type) but the same vertical stabilizer and rudder. This is for landing gross weights less than approximately 480,000lb.
In this case VMCL could exceed VSS. Boeing ensures that VREF MIN is equal to or greater than 1.23VS1g, or VMCL, or VLOC + 17kts.
VMCL and VLOC don't change with weight, as 1.23VS1g does. Looking at Flaps 30 VREF, for the -200LR/F variants, the VREF speed is 137 kts at approx 480,000 lb and below, meaning that the VREF MIN is determined from VMCL or VLOC, not 1.23VS1g.
For the Asiana 214 777-200ER(PW), the VREF is still based on 1.23VS1g(due to the VREF decreasing with weight).
It is not clear if 137kt was VREF speed or VREF+5. From the way it was reported, I am assuming 137kt was VREF+5, and VREF then was 132kt.
If VREF = 132, then VS1g = 107(divide 132 by 1.23).
Stick Shaker speed, VSS, is 3-5% above VS1g. In this case then VSS = 110-112 kt.
The top of the amber bar, minimum maneuver speed, is derived directly from the stick shaker speed, it is 1.14VSS.
Then 1.14VSS = 126 kts.
Using this data against the NTSB data, they started to advance power 7 seconds prior to impact, (at 8 seconds speed was 112 kts), right at stick shaker speed. The lowest indicated speed was reported to be 106 kts, at stall speed.
The AIRSPEED LOW EICAS msg should have displayed at approximately 23 seconds from impact.
Thread
Thread Starter
Forum
Replies
Last Post
