On 17 December 2007, an Embraer 145 being operated by Chautauqua Airlines on a Delta Connection passenger flight departing New York JFK runway 31L for an unrecorded destination carried out a high speed rejected take off in normal day visibility when the response to elevator control input at rotation was abnormal. The aircraft stopped on the runway and was subsequently able to taxy back to the gate where all 50 passengers were disembarked. Aircraft damage to the aircraft was confined to the elevator control system and to sheet metal on the horizontal stabiliser.
An Investigation was carried out by the National Transportation Safety Board (USA) (NTSB). It was noted that the runway used was 4440m long, so that there had been no risk of an overrun as a result of a high speed rejected take off.
An inspection of the elevator control system showed that both the left and right elevator control rods had fractured completely, rendering the elevator system inoperable. Both rods were found to have failed in compression in the presence of a bending moment.
It was noted that prior to the attempted take off, the aircraft had been parked outside and exposed to tailwinds of between 30 and 40 knots.
It was found that an Embraer SB had been issued for regular inspections of the aircraft type gust lock system in 2002 because of a risk of damage to that system during exposure to wind velocities which it should have been able to resist. A subsequent Brazilian AD also issued in 2002 had mandated these inspections and added a requirement to replace the mechanical gust lock system with an electromechanical one within 5 years. In February 2006, the Federal Aviation Administration (FAA) had issued a similar AD to the 2003 Brazilian one.
As a result of the NTSB Investigation, Embraer issued three successive versions of an ASB in December 2007 advising operators to carry out a detailed pre flight inspection of the elevator system until such time as the alternative electromechanical gust lock system was installed.
The FAA accepted that the interim inspections mandated by their AD had not been adequate to detect the risk of failure and therefore issued a new AD in February 2008 which largely replicated the Embraer ASB. This AD was then replaced in May 2008 by another which required repetitive inspections of mechanical gust lock systems and required their replacement with the electromechanical system within the lesser of 90 calendar days or 500 flight hours.
The full NTSB Final Report of the Investigation includes the following Probable Cause, determined by NTSB on 27 June 2011 as:
“The failure of the elevator control rods due to exposure to high winds while the aircraft was parked overnight.”
It was also noted that “
“Contributing to this incident was the failure of the existing airworthiness directive to adequately detect this discrepancy given the known deficiency with the mechanical gust lock design.”
As a result of the safety action already taken by the FAA, no Safety Recommendations were made.