Boeing 747-269B accident near Anchorage, Alaska, July 29, 1999
On July 29, 1999 at about 11:00 pm local time, a Boeing 747-269B, registered N707CK, was substantially damaged in an accident near Anchorage, Alaska. It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 5 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of a turbine blade, and subsequent penetration of the shroud (containment ring). A factor associated with the accident was the FAA's insufficient design standards/requirements addressed in an FAA Air Worthiness Directive, which called for a strengthened containment ring. The failed containment ring was in compliance with the Air Worthiness Directive.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 29, 1999 · about 11:00 pm local time
- Place
- Anchorage, Alaska · map
- Type
- Accident
- Injuries
- No one was hurt; 5 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 747-269B · all 747-269Bs on the register
- Registration
- N707CK · registry record · serial 21541
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
During climbout, the Boeing 747 crew noted a loud 'thump,' followed by a change in the number three engine instrument indications. One crewmember noted there was a fist-sized hole in the side of the engine cowling. The captain shut down the number three engine, returned to the departure airport, and landed without further incident. A postlanding inspection revealed that the inboard aileron sustained substantial damage. Disassembly of the engine revealed that there were eleven 2nd stage turbine blades that were fractured in the midspan area, and one other 2nd stage turbine blade that was elongated and necked down in the midspan area with most of the shroud tip rubbed off. The turbine exhaust case had a 16 1/2-inch long hole between the case front flange and the front mount rail. Engine service records revealed that when the turbine exhaust case was overhauled, Airworthiness Directive (AD) 96-25-10 was complied with by incorporating Chromalloy Anniston Division's, Supplemental Type Certificate (STC) SE00047AT-D. The intent of STC SE00047AT-D is to comply with FAA Airworthiness Directive (AD) 96-25-10 by increasing the wall thickness of the turbine exhaust case, thus providing enhanced containment capabilities in the event of an internal engine failure. A portion of the turbine exhaust case was sent to the NTSB Materials Laboratory for examination. A Safety Board metallurgist confirmed that both the hardness and microstructure were consistent with design specifications stipulated in Chromally Anniston Division's STC.
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
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 11,000 hours in all
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 59,727 hours
- Last inspection: continuous airworthiness programme, July 19, 1999; 268 hours since
- Maximum gross weight: 800,000 lb
- Seats: 8
- Landing gear: retractable
- Engine: P&W JT9D-7J (turbofan); 0 hours total
The flight
- Departed from: ANC Anchorage AK at 6:10 pm
- Destination: VTBD Bangkok
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 100 statute miles
- Sky: not recorded; not recorded
- Temperature: 14°F (-10°C), dew point 0°F (-18°C)
- Altimeter: 29.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 5 |
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.
Other NTSB records under N707CK the same tail number, which may have belonged to a different aircraft at the time
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.