Individually Owned: 150,657
Corporate Owned: 137,281
Mccarran International Airport
Aircraft Accident/Incident Report
Las Vegas, Nevada
Wednesday, August 6, 2008 15:40 PDT
NTSB Narrative Summary Released at Completion of Accident
The Delta Air Lines Boeing 757 airplane had just started its takeoff roll from the McCarran International Airport, Las Vegas, Nevada, when the right engine, a Pratt & Whitney (P&W) PW2037, experienced an uncontained release of high pressure turbine material. The examination of the engine revealed a hole in the high pressure and low pressure turbine case flanges at the bottom of the engine in line with the 2nd stage turbine rotor. The engine was removed from the airplane and shipped to Delta's Technical Operations Center for disassembly. The disassembly revealed four adjacent 2nd stage turbine blades were missing. In addition, the 2nd stage turbine hub had four blade retaining lugs that were fractured. Metallurgical examination of the fractures determined the fractures were due to fatigue at elevated temperatures from multiple origins along the blade slot serrations. The metallurgical examination also revealed that there were no material defects in the hub. A dimensional inspection of the hub's blades slots showed that they were missing material. Delta reported that they had to use a grit blasting procedure that was more agressive to remove the varnish-like scale from the hub in order to clean it sufficiently to permit the fluorescent penetrant inspection. Although the incident hub was only grit blasted one time, maintenance records for another PW2037 2nd stage hub that was found to have multiple cracks in the blade slots showed that it had been grit blasted multiple times to clean the hub. Grit blasting tests conducted by P&W showed that if the appropriate grit blasting procedures were not adhered to that significant material loss could result.
NTSB Probable Cause Narrative
The engine experienced an uncontained release of high pressure turbine material due to fatigue cracks that occurred on four consecutive blade retainig lugs on the 2nd stage turbine hub. The cracked lugs resulted in the release of four 2nd stage turbine blades that penetrated the engine's cases and nacelle. The lugs cracked due to loss of material and resultant increase in stress load on the blade slot serrations due to excessve grit blasting when the hub was being overhauled by Delta Air Lines. Contributing to the uncontained incident was the FAA's and Pratt & Whitney's failure to act in a timely manner when another PW2037 2nd stage turbine hub was found to have multiple cracks in the blade retaining lugs.
Event Information
| Type of Event | Incident |
| Event Date | 8/6/2008 |
| Event Day of the Week | Wednesday |
| Time of Event | 1540 |
| Event Time Zone | Pacific Daylight Time |
| Event City | Las Vegas |
| Event State | NEVADA |
| Event Country | -- |
| Zipcode of the event site | -- |
| Event Date Year | 2008 |
| Event Date Month | 8 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 360448N |
| Event Location Longitude | 1150908W |
| Event Location Airport | McCarran International Airport |
| Event Location Nearest Airport ID | KLAS |
| 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 | 2181 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 2156 Pacific Daylight Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | KLAS |
| Elevation of weather observation facility | -- |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | PDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | 10000 |
| Sky/Lowest/Cloud Conditions | Few |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 39 |
| Dew Point at event time (in degress fahrenheit) | 11 |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | -- |
| Wind Speed (knots) | 6 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | -- |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.85 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 170 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 27755 |
| NTSB Notification Source | NTSB SEA office |
| NTSB Notification Date | Aug 6 2008 12:00AM |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Dec 22 2010 3:29PM |
| User who most recently changed record | defc |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N666DN |
| NTSB Number | ENG08IA038 |
| 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 | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BOEING |
| Aircraft Model | 757 |
| Aircraft Series Identifier | 232 |
| Aircraft Serial Number | 25034 |
| Certified Max Gross Weight | 232000 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | 3 |
| Cabin Crew Seats | 4 |
| Passenger Seats | 183 |
| Total number of seats on the aircraft | 190 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | Aug 4 2008 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 58875 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Wilmington Trust Company |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | Wilmington |
| Aircraft Owner State | DE |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | -- |
| Operator is an individual? | No |
| Operator Name | DELTA AIR LINES INC |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | Hartsfield International Airport |
| 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? | 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 | Yes |
| Departure Airport Code | LAS |
| Departure City | Las Vegas |
| Departure State | NV |
| Departure Country | USA |
| Departure Time | 1540 |
| Departure Time Zone | PDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | JFK |
| Destination City | Jamaica |
| Destination State | NY |
| Destination Country | USA |
| Specific Phase of Flight | Takeoff - aborted |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Dec 21 2010 4:37PM |
| User who most recently changed record | hooj |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | 25R |
| Runway Length | 14510 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |