Individually Owned: 150,657
Corporate Owned: 137,281
N/A Airport
Aircraft Accident/Incident Report
Atlanta, Georgia 30320
Tuesady, June 21, 2011 EDT
NTSB Narrative Summary Released at Completion of Accident
On June 21, 2011, about 0007 eastern daylight time, a Boeing B-757-232, N6714Q, powered by two Pratt & Whitney (P&W) PW2037 turbofan engines, experienced a left engine (No. 1) fire while taking off from Atlanta’s Hartsfield International Airport (ATL), Atlanta, Georgia. The Captain declared an emergency, shutdown the No. 1 engine, and a turnback to ATL was initiated. The airplane made a successful overweight, single-engine landing, and an emergency evacuation was conducted on the right side of the airplane onto the runway. Of the 172 passengers and 6 crewmembers on board the flight, 3 passengers received minor injuries associated with the slide evacuation. The airplane was operated by Delta Airlines as a 14 Code of Federal Regulations Part 121 domestic passenger flight from ATL to Los Angeles International Airport, Los Angeles, California. Night visual meteorological conditions prevailed at the time, and an instrument flight rules flight plan was filed.
Examination of the engine found extensive fire damage and thermal distress in the fan and core compartments with the vast majority of the thermal distress and the most extensive fire damage located in the fan compartment between and including the intermediate case and the turbine exhaust case. The end housing of the fuel flow transmitter (FFT) was found backed-off from the main housing, which created a gap of about 0.3 inch at the bottom of the unit; correspondingly the FFT-to-fuel distribution valve (FFT-to-FDV) fuel line was found plastically deformed. An installation fit check coupled a deflection analysis of the FFT-to-FDV fuel line revealed that the deformation of the fuel tube was as a result of the FFT end housing separation; it did not cause the gap. Metallurgical analysis of the FFT hardware did not find any material defects or anomalies. Torque tension tests and a finite element analysis of the loads applied to the FFT revealed that under certain assembly variances and operational load and temperature variations, the load capability of the end housing-to-main housing bolted joint was marginal or less than marginal. With reduced load capability, the main housing threads would not be able to maintain the preload without eventually yielding, which would result in lessening of the preload and loosening of the joint. A review of the FFT component maintenance manual (CMM) found several areas where improvements could be made to ensure a more consistent FFT assembly practice and proposed changes have been initiated to the CMM.
NTSB Probable Cause Narrative
Fuel leaking from the fuel flow transmitter that ignited on contact with the engine’s hot cases which resulted in an engine undercowl fire. The fuel leak resulted from the fuel flow transmitter end housing backing off from the main housing, creating a gap that allowed high pressure fuel to escape. Under certain assembly variances and operational load and temperature variations, the end housing joint may not be able to maintain the preload without eventually yielding, which results in the loosening of the joint and the resultant gap.
Event Information
| Type of Event | Incident |
| Event Date | 6/21/2011 |
| Event Day of the Week | Tuesday |
| Time of Event | 7 |
| Event Time Zone | Eastern Daylight Time |
| Event City | Atlanta |
| Event State | GEORGIA |
| Event Country | -- |
| Zipcode of the event site | 30320 |
| Event Date Year | 2011 |
| Event Date Month | 6 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 333821N |
| Event Location Longitude | 0842541W |
| Event Location Airport | N/A |
| Event Location Nearest Airport ID | -- |
| Indicates whether the acc/inc occurred off or on an 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 | Night |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | -- |
| 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 | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | 3 |
| Injury Total None | 175 |
| Injury Total Serious | -- |
| Injury Total All | 3 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 32025 |
| NTSB Notification Source | Delta Air Lines and FAA Ops Ce |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Nov 5 2013 11:05AM |
| User who most recently changed record | scaj |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N6714Q |
| NTSB Number | ENG11IA035 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | Yes |
| Damage | None |
| Aircraft Fire | In-flight |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BOEING |
| Aircraft Model | 757-232 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 30485 |
| Certified Max Gross Weight | -- |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 178 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | -- |
| Date of Last Inspection | -- |
| Airframe hours since last inspection | -- |
| Airframe Hours | -- |
| ELT Installed | Unknown |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | DELTA AIR LINES INC |
| Aircraft Owner Street Address | 1775 AVIATION BLVD DEPT 595 |
| Aircraft Owner City | ATLANTA |
| Aircraft Owner State | GA |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 30320 |
| Operator is an individual? | No |
| Operator Name | DELTA AIR LINES INC |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | 1775 AVIATION BLVD DEPT 595 |
| Operator City | ATLANTA |
| Operator State | GA |
| Operator Country | USA |
| Operator Zip code | 30320 |
| Operator Code | DALA |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | -- |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | DALA026A |
| 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 | Yes |
| Departure Airport Code | -- |
| Departure City | Atlanta |
| Departure State | GA |
| Departure Country | USA |
| Departure Time | -- |
| Departure Time Zone | EDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | LAX |
| Destination City | Los Angeles |
| Destination State | CA |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Nov 5 2013 11:13AM |
| User who most recently changed record | scaj |
| 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 | -- |