MD-11 crash raises history of problems
The FedEx MD-11 aircraft that slammed into the runway and burst into flames Monday morning while landing at Tokyo’s Narita International Airport during windy conditions has raised the issue of the aircraft’s overly sensitive flight-control systems and reputation for being difficult to control during rough landings. Airline-related blogs have been full of discussions of the […]
March 25, 2009
The FedEx MD-11 aircraft that slammed into the runway and burst into flames Monday morning while landing at Tokyo’s Narita International Airport during windy conditions has raised the issue of the aircraft’s overly sensitive flight-control systems and reputation for being difficult to control during rough landings. Airline-related blogs have been full of discussions of the hard-landing that ultimately culminated in the total loss of the aircraft and death of both pilots. Shocking video footage of the accident shows the plane’s rear wheels hitting the tarmac with the plane’s nose lowering violently followed by a strong nose wheel bounce with the aircraft becoming airborne again, rising about 9 metres. The second touchdown was very hard on the nose wheel followed by what appeared to be collapse of the left main landing gear which possibly punctured the fuel tanks causing a massive fire to break out before the plane rolls over to the left. Substantial discussion amongst pilots and aviation experts have pointed out the difficulty in controlling MD-11 aircraft after such a ‘bounce landing’. The accident is nearly carbon-copy to one experienced by another FedEx MD-11 on 31 July 1997 while attempting to land at Newark, New Jersey. The airplane experienced a hard landing, bounced, and the right main landing gear collapsed on the second touchdown. A fire broke out after the airplane came to a stop and destroyed the airplane, but both crew and three other company personnel onboard survived. FedEx and other carriers around the world have experienced a string of accidents and incidents over the years attributed to the MD-11’s particular flight-control software prompting the US Federal Aviation Administration nearly a decade ago, to order the plane’s manufacturer to redesign flight-control systems to reduce the chances of sudden nose up or nose down maneuvers. Afterward, FedEx and other operators said the changes significantly enhanced safety by making the plane easier to control, particularly just before landings. The MD-11’s long history of problematic, highly sensitive flight-control systems is bound to be one of the major early issues examined by crash investigators. MD-11 pilots over the years have reported that the plane`s flight-control systems tend to exaggerate cockpit commands to vertically change the orientation of the nose. An entry from one blogger read: “A bounced landing must be recovered from first before allowing a big jet to settle back. Essential to get power on instantly and stop speed falling and hold attitude and stay airborne to collect your wits before deciding either go around or fly it back on. But the landing causes big speed loss and you are airborne too slow with the nose falling away from you into a fatal dive we see in the video.” Anther pilot blogger said: “I flew this airplane for a number of years and it can be a real handful to land. There is more ‘info’ on landing technique than on any other aircraft I’ve ever flown. “If you don’t get it exactly right the nose wants to come down rather violently, causing a natural tendency to over control and the nose then pitches up severely. Add strong gusty crosswinds and this beast can put your heart in your mouth. “It looks like there was an attempt to recover from that first over-reaction and then the nose hits hard – after that all bets are off. I noticed that the nose gear had not sheared off from one of the photos, so that ‘bounce/pitch over’ might have happened here at the wrong time.” Among the issues investigators are expected to examine are the speed of the landing, weather conditions including the possibility of wind shear, and what commands the pilots executed as the nose initially dropped, bounded and then pointed downward again before impact. As of August 2008, a total of 188 MD-11 aircraft of all variants were in service, including FedEx Express (58), UPS Airlines (36), Lufthansa Cargo (19), World Airways (11), KLM Royal Dutch Airlines (10) and other various operators with fewer aircraft of the type.