Boeing 737 incident near Diyarbakir, Outside the U.S., June 14, 2009
On June 14, 2009 at about 6:17 pm local time, a Boeing 737, registered TCTLA, was involved in an incident during landing (flare/touchdown) near Diyarbakir, Outside the U.S. (Diyarbakir Airport). It was flown under non-U.S. commercial rules. 2 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
An uncommanded elevator surface deflection as a result of a left elevator PCU input arm assembly jam due to FOD lodged between the input arm assembly and the PCU housing. The FOD was a roller element from an elevator upper torque tube output crank bearing, but how or when the roller element liberated from its bearing assembly could not be determined. Contributing to the survivability of this incident was the flight crew’s immediate actions in response to the elevator control system jam.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 14, 2009 · about 6:17 pm local time
- Place
- Diyarbakir, Türkiye · Diyarbakir Airport · map
- Type
- Incident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 737 4Q8 · all 737s on the register
- Registration
- TCTLA · no longer on the register · serial 25107
- Damage
- Not recorded
- Flight
- Flight · non-U.S. commercial rules
The NTSB's narrative final · quoted from the NTSB record
The Boeing 737-400 airplane experienced an uncommanded pitch up event at 20 feet radio altitude during landing. The flight crew reacted to the uncommanded pitch-up event by adjusting the stabilizer trim position, attempting to move the elevator control columns forward, disengaging the autothrottle, and executing a go-around. The airplane subsequently landed without incident and both crewmembers sustained minor injuries that were incurred during the go around. Post-incident inspection of the elevator Power Control Units (PCUs) revealed that the left elevator PCU input control arm assembly was jammed by a piece of Foreign Object Debris (FOD) in a position that offset the control arm in a downward direction. With the control arm deflected in this direction and with hydraulic pressure on, the left PCU moved the elevators to a position that pitched the airplane nose up independent of pilot input. An assessment of information obtained from the FDR regarding the functional characteristics of the airplane’s pitch control system indicates that the elevator control system was fully functional and operated as designed during previous flights and up until the uncommanded pitch event occurred. According to Boeing, a jam in either the left or right PCU input control arm assembly could result in the loss of manual control of both elevator PCUs under hydraulic-powered operation. The flight crew’s immediate actions of exerting constant and excessive force on the control columns and executing a go-around at low altitude following the jam resulted in recovery of airplane pitch control despite high control forces. Metallurgical analysis revealed that the FOD had the same dimensions and material composition as the metal rollers that are contained in a DAS10-26B1-502 bearing, which is installed in only two locations in the aft elevator control system; the right and left ends of the elevator upper output torque tube crank assembly. Post-incident inspections of the airplane’s elevator system components located within the area of the tail cone also revealed that the left hand elevator upper torque tube output crank bearing/sleeve was completely intact with all rollers present. Examination of the maintenance records revealed that the left elevator upper torque tube output crank bearing/sleeve assembly had been replaced in January 2009 to correct an elevator freeplay discrepancy on the incident airplane. However, based on the available information, it could not be determined whether the metal rollers were left behind following the maintenance work performed in January 2009 or were present before the work was performed.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Flight control sys malf/fail during landing (flare/touchdown) defining event
The NTSB's findings
- cause Aircraft › Aircraft systems › Flight control system › Elevator control system › Malfunction
- cause Environmental issues › Physical environment › Object/animal/substance › Debris/dirt/foreign object › Effect on equipment
- factor Aircraft › Aircraft systems › Flight control system › Elevator control system › Incorrect service/maintenance
- factor Aircraft › Aircraft systems › Flight control system › Elevator control system › Design
The aircraft
- Seats: 144
- Landing gear: retractable
- Engine 1: Cfm 56 (turbofan); 0 hours total
- Engine 2: Cfm 56 (turbofan); 0 hours total
- Operator: Tailwinds Airlines
The flight
- Departed from: IST Istanbul OF
- Destination: DIY Diyarbakir OF
- Flight plan: not recorded
- A second pilot was aboard
Weather at the time
- Light: not reported
- Sky: not recorded
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.