Pilots, Controller, FAA All Cited As Contributing To The Accident

The NTSB took about five hours Tuesday to come to a determination of probable cause in the accident last year over the Hudson River that fatally injured nine people, and sparked major changes in air space rules in the popular VFR corridor. The ruling could be seen as calling into question the entire concept of "see and avoid" for maintaining separation between VFR aircraft.

During the hearing, which was presented online via streaming video, witnesses recounted the events that led up to the August 8th, 2009 accident in which a Piper PA-32R-300 (N71MC) with three people on board collided with a Eurocopter AS 350 BA (N401LH) carrying five passengers on a sightseeing tour. The helicopter was determined to be about 100 feet above its planned altitude of 1,000 feet when it collided with the Saratoga. The New York Times reports that witnesses before the Board said that it was likely that the Piper pilot could have seen the helicopter, but that it would have been difficult to discern against the Manhattan skyline until just a few seconds before the collision. The approaching Saratoga would have been over the right shoulder of the Eurocopter pilot, so he would not have been likely to see the aircraft coming, according to those testifying before the Board.

Both aircraft were TIS equipped, and a failure of the pilots to use that traffic avoidance information was cited as a contributing factor in the accident. The FAA is also named for what the board called "inadequate" communications procedures and vertical separation rules in the Hudson River corridor.

But as far as "probable cause" is concerned, the NTSB cited the "inherent limitations" of 'see and avoid', as well as the actions of the air traffic controller working the flight from Teterboro. The controller was reportedly distracted by a personal phone call while on duty. The Saratoga pilot reportedly read back an incorrect frequency change instruction on the handoff to Newark Liberty Airport ATC, which made it so that ATC was unable to contact the Saratoga to warn that pilot of the impending collision.

The board voted 3-1, with one abstention, that "The NTSB determines that the probable cause of this accident was the inherent limitations of the "see and avoid" concept, which made it difficult for the airplane pilot to see the helicopter until the final seconds before the collision, and the Teterboro airport local controllers' non-pertinent telephone conversation which distracted him from his air traffic control duties including correcting the airplane pilot's readback of the incorrect frequency, and the timely transfer of communications for the accident airplane to the Newark Liberty airport tower. Contributing to the accident were 1) both pilots ineffective use of available information from the aircraft's electronic traffic advisory system to maintain awareness of nearby traffic. 2) Inadequate FAA procedures for transfer of communication among ATC facilities near the Hudson River Class B exclusion zone, and 3) FAA regulations that did not provide adequate vertical separation for aircraft operating in the Hudson River Class B exclusion zone."

FMI: www.ntsb.gov