Monday, November 30, 2009

NTSB says: Wake Turbulence From 767 Likely Caused Mexican Lear Crash

The crash of a Learjet in Mexico City that was originally suspected to be the result of terrorism and sabotage has now been determined to be the result of wake turbulence caused by improper inflight aircraft management.
The following information has just been released by the NTSB. It was submitted to Silver Wings by Jim Davis.

US and Mexican investigators speculate the downing of a Learjet 45 in Mexico City on November 4 was caused by the combination of wake turbulence from a landing airliner and the pilots’ unfamiliarity with the aircraft.

The plane’s cockpit data recorder, analyzed by the National Transportation Safety Board in Washington, DC, revealed the pilots' last words – "Diosito" (My little God) – in their struggle to regain control of the aircraft as it encountered severe wake turbulence.
Theories of sabotage have been all but ruled out in the deaths of all nine persons on board, including Mexico's Interior Minister, Juan Camilo Mouriño, and José Luis Santiago Vasconcelos, well known for his fight against drug cartels.

Pilot Martín Oliva, 39, and co-pilot Alvaro Sánchez, 58, have been defended by their families as responsible, serious professionals, the Dallas Morning News reported.
But at a news conference, Mexico's Communications and Transportation Minister Luis Telléz said, "The investigation revealed apparent deficiencies in the training and certification process of both [pilots]," and alleged the pilots failed to follow ATC instructions.
As the Learjet approached Mexico City, it was sequenced behind a Boeing 767-300 and given instructions to reduce airspeed in order to maintain proper spacing behind the airliner, Telléz said. But the pilots took over a minute to comply with the speed reduction, putting their plane just 4 nm behind the much larger 767.

Investigators said that wake turbulence from the 767 caused the Learjet to crash within 30 seconds, evidenced by the plane's Cockpit Voice Recorder:

Pilot: "That one's got some turbulence."
Co-pilot: "Hey man."
Pilot: "Hey [expletive]."
Pilot: "Alvaro, what do we do, Alvaro?"
Co-pilot: "Hand it over to me, hand it over to me, hand it over to me."
Pilot: "It's yours Alvaro."
Pilot: "[expletive]"
Pilot: "No, Alvaro."
Co-pilot: "Diosito."