Individually Owned: 150,657
Corporate Owned: 137,281
Hartsfield-Jackson Atlanta Int Airport
Aircraft Accident/Incident Report
Atlanta, Georgia
Sunday, October 23, 2011 14:15 EST
NTSB Narrative Summary Released at Completion of Accident
An Atlantic Southeast Airways (ASA) Bombardier Canadair Regional Jet (CRJ)-700 experienced an undercowl engine fire after landing at Hartsfield-Jackson Atlanta International Airport (ATL), Atlanta, Georgia. The pilot shut down the affected engine and the fire warning quickly ceased. No fire bottles were discharged. The airplane taxied to the gate and the passengers deplaned normally. The airplane was undamaged and no injuries were reported. The incident flight was a 14 CFR Part 121 regularly scheduled passenger flight from a Des Moines Airport, Iowa, to ATL.
Examination of the engine revealed that the Start Operability Bleed Valve (OBV) fuel return adapter-fitting had fractured and the electrical harness in the vicinity of the OBV was sooted and thermally damaged. No cowling damage was noted. Metallurgical examination of the fractured fuel return adapter-fitting revealed that it had failed in fatigue due to cyclic loading. The return adapter-fitting tube end ball-nose area had a dent. Material deposits were found outboard of the sealing area and axial scrape marks were found beneath and adjacent to the deposited material. The valve flow body flange of the OBV also exhibited a dent and material deposit. An analysis of the deposited material revealed elemental peaks of silicon and oxygen, elements present in sand and not in the return adapter-fitting alloy composition. The presence of silicone and the dent is consistent with the OBV most likely having been dropped and impacted a hard surface that damaged the fuel return adapter-fitting before it was reinstalled on the engine. The impact damage to the return adapter-fitting reduced its loading-carrying and fatigue capability. The OBV fuel return adapter-fitting eventually fractured and separated, which allowed fuel to spill onto a hot engine case that ignited the undercowl fire.
Although not related to the incident, testing and analytical modeling of the OBV adapter-fitting joint revealed that, as designed, the joint is directly affected by variations in the applied preload caused by differences in installation torque, coefficient of friction, application of a primer on the serrations, and use of the combination installation tool and that static applied loads were sufficient to create loose contact between the adapter-fitting and the OBV piston housing threads. Vibratory loads during normal engine operation can create relative motion between the adapter-fitting and the piston housing threads generating a wear mechanism that can eventually lead to a fatigue separation of the piston housing threads and the pull-out of the adapter-fitting and subsequent fuel leaks that could lead to a fire. To address this design deficiency, service bulletins were issued to replace the affected OBV with an OBV from alternate manufacturer, and the removal schedule was based on the amount of flight time each OBV had accumulated. The FAA issued an Airworthiness Directive mandating the service bulletins.
NTSB Probable Cause Narrative
The Start Operability Bleed Valve (OBV) fuel return adapter-fitting fractured and separated in cyclic fatigue, which allowed fuel to spill onto a hot engine case that ignited the undercowl fire. The OBV fuel adapter-fitting was dropped and the damage reduced its load carrying and fatigue capability, eventually leading to its failure.
Event Information
| Type of Event | Incident |
| Event Date | 10/23/2011 |
| Event Day of the Week | Sunday |
| Time of Event | 1415 |
| Event Time Zone | Eastern Standard Time |
| Event City | Atlanta |
| Event State | GEORGIA |
| Event Country | -- |
| Zipcode of the event site | -- |
| Event Date Year | 2011 |
| Event Date Month | 10 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | -- |
| Event Location Longitude | -- |
| Event Location Airport | Hartsfield-Jackson Atlanta Int |
| Event Location Nearest Airport ID | ATL |
| 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 | -- |
| 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 | -- |
| 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 | -- |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 31274 |
| NTSB Notification Source | Operator |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | May 7 2013 7:47AM |
| User who most recently changed record | scaj |
| Basic weather conditions | -- |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N751EV |
| NTSB Number | ENG12IA004 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | -- |
| Flight plan Was Activated? | -- |
| Damage | None |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BOMBARDIER |
| Aircraft Model | CL600 2C10 |
| Aircraft Series Identifier | 701 |
| Aircraft Serial Number | 10163 |
| 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 | -- |
| 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 | -- |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | -- |
| Aircraft Owner State | -- |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | -- |
| Operator is an individual? | No |
| Operator Name | ATLANTIC SOUTHEAST AIRLINES INC |
| Operator Same as Owner? | No |
| 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 | ASOA |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | ASOA029B |
| 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 | -- |
| Departure Airport Code | -- |
| Departure City | -- |
| Departure State | -- |
| Departure Country | -- |
| Departure Time | -- |
| Departure Time Zone | -- |
| Destination Same as Local Flt | -- |
| Destination Airport Code | -- |
| Destination City | -- |
| Destination State | -- |
| Destination Country | -- |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Dec 17 2012 2:55PM |
| 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 | -- |