Individually Owned: 150,657
Corporate Owned: 137,281
Diyarbakir Airport
Aircraft Accident/Incident Report
Diyarbakir
Sunday, June 14, 2009 18:17 UTC
NTSB Narrative Summary Released at Completion of Accident
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.
NTSB Probable Cause Narrative
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.
Event Information
| Type of Event | Incident |
| Event Date | 6/14/2009 |
| Event Day of the Week | Sunday |
| Time of Event | 1817 |
| Event Time Zone | Coordinated Universal Time? Same as GMT |
| Event City | Diyarbakir |
| Event State | -- |
| Event Country | -- |
| Zipcode of the event site | -- |
| Event Date Year | 2009 |
| Event Date Month | 6 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | -- |
| Event Location Longitude | -- |
| Event Location Airport | Diyarbakir Airport |
| Event Location Nearest Airport ID | LTCC |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Unknown |
| Time of the weather observation | |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | -- |
| Elevation of weather observation facility | -- |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | -- |
| Lighting Conditions | Not Reported |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | Unknown |
| Sky Condition for Lowest Ceiling | -- |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | -- |
| Air Temperature at event time (in degrees celsius) | -- |
| Dew Point at event time (in degress fahrenheit) | -- |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | -- |
| Wind Speed (knots) | -- |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | -- |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | -- |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | Minor |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | 2 |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | 2 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | -- |
| NTSB Notification Source | Boeing |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Sep 23 2010 10:57AM |
| User who most recently changed record | schd |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | TC-TLA |
| NTSB Number | ENG09IA011 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Non-U.S., Commercial |
| Type of Flight Plan filed | Unknown |
| Flight plan Was Activated? | -- |
| Damage | None |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BOEING |
| Aircraft Model | 737 |
| Aircraft Series Identifier | 4Q8 |
| Aircraft Serial Number | 25107 |
| Certified Max Gross Weight | -- |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | 2 |
| Cabin Crew Seats | -- |
| Passenger Seats | 144 |
| Total number of seats on the aircraft | 144 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | -- |
| Date of Last Inspection | -- |
| Airframe hours since last inspection | -- |
| Airframe Hours | -- |
| ELT Installed | No |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | Unknown |
| Aircraft Owner Name | Tailwinds Airlines |
| Aircraft Owner Street Address | IDTM A2 Blok No:395 |
| Aircraft Owner City | Yesilköy |
| Aircraft Owner State | -- |
| Aircraft Owner Country | TU |
| Aircraft Owner Zipcode | -- |
| Operator is an individual? | No |
| Operator Name | Tailwinds Airlines |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | -- |
| Operator City | -- |
| Operator State | -- |
| Operator Country | USA |
| Operator Zip code | -- |
| Operator Code | -- |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | Scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | -- |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | IST |
| Departure City | ISTANBUL |
| Departure State | -- |
| Departure Country | TU |
| Departure Time | -- |
| Departure Time Zone | -- |
| Destination Same as Local Flt | -- |
| Destination Airport Code | DIY |
| Destination City | Diyarbakir |
| Destination State | -- |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Apr 19 2010 8:23AM |
| User who most recently changed record | haum |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |