WPR13GA374 · McDonnell Douglas Helicopter 369E
P J Helicopters McDonnell Douglas Helicopter 369E · Accident: loss of engine power (total) while maneuvering
From Burns, OR to Burns, OR
Event
- NTSB case
- WPR13GA374
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Government
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
McDonnell Douglas Helicopter 369E
- Aircraft type
- McDonnell Douglas 369
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N62PJ
- Operator
- P J Helicopters
- Onboard fatalities
- Unknown
- Route
- From Burns, ORTo Burns, OR
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Public Aircraft
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Maneuvering · low-altitude flying
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of engine power (total)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft power plant
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The commercial pilot was conducting a local public flight. He reported that, during cruise flight about 400 ft above ground level over densely wooded mountainous terrain, he heard a "loud bang" emanate from the engine, followed by a left yaw and a "severe medium frequency vibration." The pilot subsequently performed a 180-degree, left-turn autorotation to a nearby forest service logging road. During the landing, the main rotor blades struck trees adjacent to the road, and the left skid slid into a ditch, which resulted in the subsequent separation of the left skid.
Postaccident examination of the airframe and engine revealed that one 4th-stage turbine wheel blade had fractured at the blade root and that several additional turbine blades exhibited damage. Metallurgical examination of the fracture surface area revealed that it exhibited signatures consistent with low-cycle fatigue cracking that had progressed to high-cycle fatigue cracking, which led to the failure of the blade due to overload and resulted in the subsequent loss of engine power. Fluorescent penetrant inspection of the 4th-stage turbine wheel did not reveal any other cracks. In addition, the microstructure, hardness, and composition of the 4th-stage turbine wheel conformed to the engineering drawing requirements.
A review of the maintenance logbooks revealed that the 4th-stage turbine wheel was part of a post-service bulletin (SB) commercial engine bulletin (CEB)-1365 or "enhanced" power turbine assembly design. According to the engine manufacturer, the pattern and appearance of the fracture on the accident wheel was similar to fractures on the wheels involved in eight other failures of the post-SB CEB-1365 power turbine assembly design. Representatives from the engine manufacturer reported that the low-cycle fatigue crack was likely initiated by a combination of two factors: (1) a high, positive thermal gradient in the airfoil trailing edge material near the hub during the engine starting process; and (2) the subsequent high, negative thermal gradient and high-speed stress into the blade during transient operation, such as autorotation.
Probable cause
The total loss of engine power during cruise flight due to the separation of one of the 4th-stage turbine wheel blades due to low-cycle fatigue cracking that had progressed to high-cycle fatigue cracking, which ultimately led to the overload failure of the blade.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR13GA374
- Event ID
- 20130815X32337
- Case number
- WPR13GA374
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 4bd12b527f2a9212a85cc62f853ae6ba56aaa01f5578a76e12a06156623e7c92; retrieved 2026-09-15T22:32:24.811Z.