DCA08IA019

Prior to the incident flight, the Embraer EMB-145 was parked overnight with its tail pointed into the wind. During this time period, the winds were reported to be very high (on the order of 30-40 kts). The aircraft was equipped with a mechanical gust lock system designed to immobilize the forward torque tube of the elevator control system when the system is engaged. During takeoff, the flightcrew performed an emergency high-speed aborted takeoff because the captain felt a control anomaly during rotation. An inspection of the elevator control system components revealed that both left and right elevator control rods had fractured completely, rendering the elevator system inoperable. The elevator control rods fractured when the elevator surfaces repeatedly moved off the rear elevator stops due to wind gusts.

An airworthiness directive issued by the Federal Aviation Administration (AD 2005-26-15) was already in place at the time of this incident, which mandated replacement of the mechanical gust lock system on the Embraer 145 airplane with a more effective electromechanical gust lock system and required some repetitive inspections be performed until such time as the electromechanical system was installed. However, based on the findings in this incident, the FAA determined that the interim inspections mandated by AD 2005-26-15 were not adequate to detect the discrepancies exhibited in this event. As a result, the FAA subsequently issued a new airworthiness directive (AD 2008-03-03) to improve the interim inspections required until terminating action was taken by operators and also superceded AD 2005-26-15 with AD 2008-10-08 to shorten the compliance time for installation of the electromechanical gust lock system.

History of flight

On December 17, 2007, at 3:30 pm, Eastern Standard Time, the flight crew of a Chautauqua Airlines Embraer EMB-145 performed an emergency high-speed aborted takeoff at John F. Kennedy International Airport (JFK) due to a serious elevator malfunction. The malfunction completely disabled the elevator system of the aircraft, either before or while the captain was rotating the aircraft for flight. The captain stated that during the rotation maneuver he felt an anomaly that caused him to abort the takeoff and stop the aircraft. Taxi back to the gate was uneventful and all 50 passengers and three flight deplaned normally.

Injuries to persons

No injuries were reported.

Damage to airplane

Following the incident, an internal inspection of the elevator control system components revealed that both left and right elevator control rod assemblies (P/N 145-22141-405) had fractured completely through their circumferences rendering the elevator control of the aircraft inoperable. In addition, damage to control stops and horizontal stabilizer sheet metal was observed. A metallurgical examination of the control rods indicated that both failed in compression with some bending moment observed.

Other damage

None.

Aircraft information

A gust lock system is installed on the aircraft to lock the elevator to avoid damage to elevator components when the aircraft is subjected to strong gusts on the ground.

The EMB 145 can be equipped with either a mechanical gust lock system or an electromechanical gust lock system. The incident aircraft was equipped with a mechanical gust lock system. The mechanical gust lock is designed to immobilize the forward torque tube, which is attached to the control column, when it is engaged. Some stretching of elevator cables will occur when the elevator surface is exposed to high loads.

The electromechanical gust lock system uses a locking mechanism that acts directly on the elevator. The gust lock lever in the cockpit activates an electromechanical actuator that drives locking pins into the elevator panels. No stretching of the elevator cables can occur with the electromechanical gust lock system engaged.

On September 27, 2002, Embraer issued Service Bulletin 145-27-0087 which called for repetitive inspections of components of the elevator system due to possible damage caused by strong wind gusts on the ground.

On November 8, 2002, the Brazilian Servico Publico Federal Departamento de Aviacao Civil issued Airworthiness Directive 2002-01-01R3, with similar instructions to operators. This airworthiness directive also called for the replacement of the mechanical gust lock system with an electromechanical system within 10,000 flight hours or 60 calendar months. This AD only applied to Brazilian registered airplanes.

On February 3, 2006, the FAA issued airworthiness directive 2005-26-15, that required US operators of EMB 145 aircraft to also perform similar repetitive inspections and also install electromechanical gust lock systems within 10,000 flight hours or 60 months.

In response to the Chautauqua Airlines JFK incident, Embraer issued Alert Service Bulletin 145-27-A106R0 on December 23, 2007. This service bulletin advised operators to perform a detailed inspection of the elevator control system (including a check to insure that the elevators responded properly to control column inputs) within the next 20 flight hours, and it also advised the operators to repeat these inspections any time the aircraft was exposed to wind gusts over 35 knots while on the ground. This service bulletin only applied to aircraft that did not already have the electromechanical gust lock system installed.

This service bulletin was revised on December 27, 2007. The revised service bulletin advised operators to perform the detailed inspection of the elevator control system, perform a daily check prior to the first flight of the day to insure proper elevator response to control column movements, and to repeat the detailed elevator control system check every 600 flight hours or if the aircraft is exposed to wind gusts over 50 knots while on the ground. These actions would be no longer required when an electromechanical gust lock system was installed on the aircraft.

The service bulletin was revised again on December 28, 2007. This revision modified the daily elevator inspection to include a provision for performing a detailed check of the elevator skin around the hinge areas while the elevators were held in a trailing edge up position.

The FAA incorporated the service bulletin’s recommended actions (with some minor revisions) in Airworthiness Directive AD 2008-03-03, effective February 14, 2008.

And last, on May 23, the FAA issued AD 2008-10-08. This AD superseded AD 2005-26-15, called for repetitive inspections, and shortened the compliance time for the electromechanical gust lock retrofit to 90 days after May 23, 2008, or 500 flight hours, whichever occurs first.

All EMB 145 aircraft now have electromechanical gust lock systems.

Meteorological information

Prior to the accident flight, the aircraft was parked overnight at JFK airport with its tail pointed into the wind. During the night the winds were reported to range between 30 and 40 knots.