Flight 587 - programme summary
265 people died when an Airbus operated by American Airlines crashed into the New York suburb of Queens in November 2001. The twin-engined jet took off from John F Kennedy Airport in fine conditions but hit trouble after just 67 seconds. In the following 38 seconds the plane started to disintegrate before nose-diving into the residential Rockaway area of the city.
"It looked beautiful in the last seconds of its life"
Patrick Twohig, eyewitness
Everyone aboard was killed (along with five people on the ground) so the crash investigators had to rely on eyewitnesses, recovered parts of the plane and information from both air traffic control and the flight data recorders. The discovery of the Airbus' vertical tailfin hundreds of metres from the fuselage immediately focussed attention on whether the pilots lost the ability to control the plane.
Why the tailfin detached was at the heart of the investigation by the National Transportation Safety Board. The airline and the manufacturer blame each other for creating a situation in which the stress on the rudder and tailfin exceeded the so-called ultimate load, the worst-case scenario set by the Federal Aviation Administration (FAA). A number of American Airlines pilots have taken matters into their own hands though: requesting transfers to other aircraft because of their safety concerns.
"Sten Molin was an above average pilot"
Captain Delvin Young, American Airlines
On the flightdeck of the Airbus A300-600 on 12 November 2001 were Captain Ed States and (at the controls) First Officer Sten Molin, both highly experienced commercial pilots. They had been warned by airport controllers of the risk of 'wake turbulence' from a Boeing 747 that had taken off just before them.
Wake turbulence vortices act like horizontal tornadoes, spilling off the wing tips of aircraft and trailing for miles behind them. Another plane hitting the disturbed airstream can be thrown around alarmingly. Both Molin and States had been trained to cope with wake turbulence. Investigators are sure Flight 587 did fly into the wake of the 747 ahead. What happened next?
- On the cockpit voice recording, bumps and rattles are heard before Molin confirms to Captain States that he feels OK handling the plane.
- The 'black box' data recorder shows that Molin then continued to try to adjust the Airbus' angle back to a level attitude.
- Unlike most pilots, he used the foot pedals to swing the rudder, rather than solely relying on the ailerons (wing flaps) to control the pitching.
The use of the rudder to counter wake turbulence may have created forces too great for the tailfin to withstand.
"I don't fly that airplane any more"
Captain Robert Tamburini, American Airlines former Airbus pilot
The Airbus 300's lightweight tail
Initial suspicion fell on the Airbus' innovative construction because in 70 years of commercial aviation, no other airliner has ever lost a tailfin. By forming the fin of laminate composites instead of aluminium, Airbus Industrie made a weight saving that converts into more revenue for the operator.
When the loads on the tail of the crashed plane were assessed by investigators, the calculated stress on the tailfin exceeded the designers' 'ultimate load' set by the FAA. So even though the Airbus' revolutionary tailfin had clearly failed eventually, it had still performed to its certified standard. The composite construction was not to blame, in Airbus' view.
A number of American Airlines pilots do have their doubts about the lightweight Airbus construction method. They believe that traditional metal structures are easier to check for early signs of wear, pointing to another A300 thought to have flown with tailfin damage for four years after a visual inspection had failed to spot anything. (American Airlines checked its entire A300 fleet for tailfin damage after the November 2001 disaster. It was given the all clear.)
Claim and counterclaim
The actions of pilot Sten Molin were once more the subject of detailed investigation. Why did he move the rudder repeatedly from side to side?
Airbus Industrie argue that American Airlines' training programme contributed to the crash by teaching pilots to use the rudder in certain instances. Airbus has demonstrated in a simulator how wing controls alone can handle a wake turbulence encounter, and says that in these circumstances the rudder should never be used.
The airline counters that their pilots were safely trained and that there is evidence Airbus failed to inform them about potential dangers with the rudder design, evidence that was available from earlier incidents.
Since the crash, air safety regulators worldwide have issued bulletins to ensure pilots understand the problems of dealing with wake turbulence. American Airlines continues to operate A300 jets.