How can pilots forget to set flaps on takeoff & cause fatal crash? Is it an annual or biannual event?
Spanish CIAIAC accident investigation commission issued a 92 page, exemplary report in 2009 and another recently.
The conclusion was that this accident was pilot error and the aircraft was not configured correctly for take off. I would now like to explain to you in simple terms on what should happen on taxi out and take off.
Firstly let me explain what flaps are. These are large airfoil shaped sections situated at the front and rear of the wing that can be selected to increase the area of the wing so that the aircraft can fly relatively slowly.
On taxi out towards the runway the pilots are reading and responding to the ‘Check List’. One of the most important items would be Pilot 1 “ Flaps to Take Off”, Pilot 2 would then put the flap lever down to Take off, check that the flap position indicator gauge shows the rear flaps are at TO position and check that the lights indicating the Leading Edge flaps are deployed, are on.
Pilot 2 replies “Flaps set, Leading edges deployed.” The wing has now been temporarily modified to allow it to lift the aircraft at low speed. If the flaps are not deployed then the Take Off Warning System (TOWS) is activated by the throttles and as power is applied a Klaxon sounds warning the pilots to check again before take off.
An intrusive but necessary Cockpit Voice Recorder is always running and on that afternoon the CVR did not record the pilots carrying out the flap selection part of the of the check list and, ironically no TOWS Klaxon was heard as the throttles were opened for take off. The aircraft got airborne for a few seconds, had inadequate lift (stalled) and crashed. It is impossible for an MD-82 aircraft to take off without the wing flaps deployed.
The Investigation report A-032/2008 stated that the flap selector lever was still in the up position and that the mechanisms to deploy the flaps known as screw jacks were in the stowed (up) position, The electrical parts that operated the TOWS were found and although with some fire damage tested extensively but could not be faulted. Of course everyone accepts this warning did not trigger on this occasion because apart from no recording I assure you if that Klaxon starts up in the cockpit you can’t even think straight you just want to stop it!
Apart from the Spanish CIAIAC highly professional and thorough reports, a number of ‘investigation committees” have been set up by Judges and others to try to revert the conclusion of pilot error; this is still on going. I will say that the TOWS should be improved, although no warning system is infallible and cannot be relied on totally.
Finally close to the time of the incident an Air Europa B737 took off from Tenerife without flaps but put them down in time to save the aircraft. The B737 if far more forgiving than the MD82.
Other incidents have been recorded, usually fatal.
I send my sincere condolences to family and friends of those that died.
By Geoff Jones
Geoff spent over 40 years working in the aviation industry
Photo credit: Javier Pedreira