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01-14-2013, 12:29 PM

#60

xjtguy

Banned

Joined APC: Aug 2011

Posts: 1,134

Quote:

Originally Posted by forgot to bid

MD-11.org - Your best source for MD-11 information and Training

Assembly of the first MD-11 began on March 9, 1988, and the mating of the fuselage with wings occurred in October that year. The first flight was originally planned to occur in March 1989, but numerous problems with manufacturing, supplier delays, and labor actions resulted in delays. A ceremonial roll out of the prototype occurred in September of that same year.
The following months were used to prepare the prototype for its maiden flight, that finally happened on January 10, 1990. The first two aircraft manufactured were intended for FedEx, and thus were already fitted with the forward side cargo door. They remained with the manufacturer as test aircraft until 1991 before being completely converted to freighter and delivered to their customer. FAA certification was achieved by November 8, 1990. The first MD-11 delivered to a customer went to Finnair on December 7, 1990. This particular aircraft accomplished the first revenue service by an MD-11 on December 20, 1990, when the aircraft carried passengers from Helsinki to Tenerife in the Canary Islands. The first MD-11 service in the U.S. was inaugurated by Delta Air Lines, also in 1990.

It was during this period that deficiencies in the MD-11's performance began to surface. It failed to meet its targets for range and fuel burn. American Airlines in particular was unimpressed, as was Singapore Airlines, who canceled its order for 20 aircraft. The P&W-powered MD-11 should have been capable of a 7,000 nautical mile range with 61,000 pounds of payload. The aircraft could only achieve its full range with 48,500 lbs of payload, or a reduced range of 6,493 nm with a full payload.

In 1990, McDonnell Douglas with Pratt & Whitney and General Electric began a modification program known as the Performance Improvement Program (PIP) to improve the aircraft’s weight, fuel capacity, engine performance, and aerodynamics. McDonnell Douglas worked with NASA's Langley Research Center to study aerodynamic improvements. The PIP lasted until 1995 and successfully recovered the range and fuel burn deficiencies. However, the damage caused by the failure of the initial deliveries of the MD-11 to meet the performance goals was unrecoverable. It was then that McDonnell Douglas entered into negotiations with Boeing on a merger plan.

McDonnell Douglas merged with Boeing in 1997, and the new company announced that MD-11 production would continue as a freighter. However, in 1998 Boeing announced it would end MD-11 production after filling current orders. The last MD-11 was delivered to Lufthansa Cargo on February 22, 2001. The delivery of this aircraft ended a production run of 200 aircraft, and also ended a chapter in aviation history. The Douglas label disappeared after Boeing acquired the company in 1997.

With no other cargo aircraft being offered in the same weight and performance category, the MD-11 became highly sought after by cargo airlines. Because of this, resale prices of MD-11s remained high. Passenger airlines seized this opportunity to sell their MD-11s to cargo airlines, and purchase aircraft in the Boeing 777 category (which, at the time, was not offered in a cargo version). The majority of the MD-11 fleet has now been converted to cargo configuration. With a new mission comes a new lease on life, and the MD-11 will continue in active service throughout the world for many years to come.

Before the 777F came along, here's a lengthy write up of why they were more popular for freight ops;

Quote:

When selecting a freighter, the operate looks for an aircraft with a very large spread between MLW (Max Landing Weight) and EW (Empty Weight). This is the amount of cargo that can be carried. Freight operators are looking for a large spread as a proportion of the EW, or how much dead weight you have to carry per pound of cargo. For large freight volumes, the MD11, DC10, 747F and even DC8 is very attractive in this regard.

As it turns out, for most common cargo loads, the MD11/DC10 run out of lift and cargo capacity (volume) at about the same time. The 747's tend to run out of lift before they run out of volume.

So a 777 or A330 or even 747 may be able to carry the cargo further, but the reality is that cargo does not mind if it takes 18 hours to cross the Pacific Ocean or 14 hours, and cargo does not mind what route it takes - passengers do and they need to be fed and entertained along the way.

So for freight operations, carrying a larger amount of freight and less fuel, and then refueling enroute, can make for more efficient operations than long distance point to point operations.

The other number that is of interest to freight operators is the ratio of fuel burn per hour / (MGTW-MLW). This is basically the range, and as long as this number is 5100 miles, it works well for freight ops. Remember that freights tend to operate between freight hubs, so the longer runs tend to be such as ANC-HKG or HNL-SYD. Look at the operations in/out of ANC and HNL each night and you will see how they operate as freight hubs.

On the other hand, passengers operations require longer range non-stop services. Passengers don't want to stop in ANC or HNL for fuel between USA and Asia.

So if we consider the operational numbers for a passenger MD11 flying, say LAX-HKG, we find EW=295,000 lb, MLW=440,000 lb, and MGTW=630,000 lb. Any flight that consumes more than 190,000 lb of fuel is converting payload into fuel at a rate of about 3lb/mile. LAX-HKG is about 15 hours much of the year (due to winds) and at about 16,000lb/hr fuel burn plus gound and climb usage (say another 15,000lb), we will consume about 255,000lb of fuel.

Now subtract this 255,000lb fuel from MGTW and you get 375,000lb max landing weight, of which about 10,000lb will be fuel reserves. This leaves us a total of 70,000lb of usable payload for passengers, cabin amenities, luggage, catering etc. This means we have a severe passenger restriction for this flight.

If you perform this same long-haul non-stop passenger service with a 747-400 (as CX does), you will consume about 330,000lb of fuel, and need about 12,000 reserves, so 875,000lb (MGTW) less 342,000lb fuel give us 533,000lb MLW against a EW of 398,000lb, or 135,000lb uplift capacity to work with instead of 70,000 lb for the MD11, which is a whole lot more realistic and viable.

These numbers are much more attractive for the B777 and newer A340's for non-stop long haul passenger operations. Hence the demise of the MD11 as a passenger airliner, while it continues to be an admirable freighter.

Now suppose I want to fly freight LAX-HGK non-stop. MLW of my MD11F = 480,000lb and EW = 265,000lb, while MGTW = 630,000lb. We are still going to consume 255,000lb of fuel and require 10,000lb fuel reserves, so I have 365,000lb MLW. Take away the EW and this gives me 100,000lb of cargo payload.

However, what happens if I choose to give my cargo a break in ANC on the way? This will add about 200 miles to the flight, out of more than 7000 miles total, and of course we burn more fuel for the extra takeoff and landing, as well as about 2 hours additional time.

LAX-ANC is about 2350 miles and will take about 5 hours, burning 90,000lb of fuel. Since this 90,000lb of fuel is way less than the spread of MLW and MGTW, this sector is limited only by max landing weight. That means my payload can be the entire spread between EW and MLW less the required fuel reserves, so I can carry about 206,000 lb of cargo.

ANC-HKG is 5080 miles and against prevailing winds is likely to take about 11 hours, consuming about 175,000lb of fuel, plus 15,000lb for ground and climb out, plus 10,000 reserves, making fuel requirements about 200,000lb. This makes the payload 430,000-265,000=165,000lb (MGTW-InitialFuel-EW). So my two-hour fuel stop in ANC has increased my payload by 65%, while fuel costs rise about 10% and crew costs up slightly.

But passengers would not appreciate the 2-hour fuel stop in ANC! Freight does not complain, and does not need toilet breaks etc.

Freight operators like Fed-ex that get very good utilization out of their aircraft ensure that the operating cost efficiencies of their new MD11's (for freight ops as described above) outway the capital costs. For freight operators that have much lower aircraft utilisations, the capital costs are a more significant function and they will tend to look for less expensive purhcase costs and older DC10, B747, A300 and even DC8 aircraft fit their needs better.

So MD11's make good freights so long as you don't try to fly them further than the spread between MGTW-MLW. 777 makes a great pax airline because passengers don't want to take an extra 2 hours to fly long-haul ops.