Douglas DC9 incident near Minneapolis, Minnesota, June 15, 2010
On June 15, 2010 at about 1:45 am local time, a Douglas DC9, registered N671MC, suffered minor damage in an incident near Minneapolis, Minnesota (Minneapolis - St. Paul Interna airport). It was flown under rules the NTSB did not record. The NTSB record does not give the injuries. The weather was conditions the NTSB did not record.
The NTSB's probable cause their words, unchanged
The failure of the facility that overhauled the 1st stage fan blade to properly restore the leading edge, which caused a flutter mode resulting in a fatigue crack and fracture of the fan blade.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 15, 2010 · about 1:45 am local time
- Place
- Minneapolis, Minnesota · Minneapolis - St. Paul Interna · map
- Type
- Incident
- Injuries
- The NTSB record does not give the injuries.
- Weather
- conditions the NTSB did not record
- Aircraft
- Douglas DC9 51 · all DC9s on the register
- Registration
- N671MC · registry record · serial 47660
- Damage
- Minor damage
- Flight
- Flight · rules the NTSB did not record
The NTSB's narrative final · quoted from the NTSB record
On June 4, 2010, a Delta Air Lines Boeing DC9-51, N671MC, had a case-uncontained, nacelle-contained 1st stage fan blade separation in the No. 1 (left) engine, A Pratt & Whitney (P&W) JT8D-17 turbofan, during a ground run for maintenance at the Minneapolis-St. Paul International Airport. Delta Air Lines maintenance personnel were conducting a trim run on the No. 2 (right) engine. After they had checked the No. 2 engine's power, they advanced the No. 1 engine's throttle to check its power when at about 1.7 EPR [engine pressure ratio], they heard a boom and felt a vibration. They shut down the engines and upon exiting the airplane, noticed the No. 1 engine's fan blades were damaged. One 1st stage fan blade was completely missing from the front compressor front hub's blade slot. Several pieces of the missing 1st stage fan blade were recovered from the engine's fan duct. The metallurgical examination of the fan blade pieces revealed a fatigue fracture on the blade's suction-side blade root bedding flank. In addition, there were fatigue fractures on the fractured fan blade's suction-side midspan shroud from the upper and lower surfaces of the shroud. A dimensional inspection of the fractured fan blade's leading edge revealed the radius was 0.035 inch in comparison to the required 0.009 inch. According to P&W, the leading edges of the 1st stage fan blades erode during normal operation. However, P&W also advised that the amount of wear observed on the separated blade would be associated with approximately 11,000 flight cycles rather than the engine's 2,685 flight cycles since the last overhaul, during which the 1st stage fan blades were overhauled. According to P&W, a worn and blunt leading edge can cause a flutter mode that can lead to increased stresses in the fan blade and cause fatigue fractures in the root and airfoil. The erosion of the fan blade leading edge was likely the result of faulty restoration of the leading edge profile or failure to restore the leading edge in a timely manner.
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
- Uncontained engine failure defining event
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Compressor section › Failure
- factor Personnel issues › Task performance › Maintenance › Repair › Maintenance personnel
The aircraft
- Airframe total time: 69,397 hours
- Maximum gross weight: 122,000 lb
- Seats: 131
- Landing gear: fixed
- Engine 1: Pratt And Whitney JT8D-17 (turbofan); 0 hours total
- Engine 2: Pratt And Whitney JT8D-17 (turbofan); 0 hours total
- Operator: Delta Air Lines
The flight
- Departed from: KMSP Minneapolis MN
- Destination: KMSP Minneapolis MN
- Flight plan: none
Weather at the time
- Light: daylight
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
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.