Aerospatiale AS 355F1 accident near Makakilo City, Hawaii, March 3, 2012
On March 3, 2012 at about 3:40 am local time, a Aerospatiale AS 355F1 (helicopter), registered N101MZ, was substantially damaged in an accident during maneuvering (hover) near Makakilo City, Hawaii. It was an external-load flight under external-load helicopter rules (Part 133). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
A partial loss of engine power while maneuvering over rough/uneven terrain that was precipitated by the failure of a 3rd stage turbine blade as a result of high-cycle fatigue.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 3, 2012 · about 3:40 am local time
- Place
- Makakilo City, Hawaii · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerospatiale AS 355F1 · all AS 355F1s on the register
- Registration
- N101MZ · registry record · serial 5045
- Damage
- Substantial damage
- Flight
- External-load flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
During external load operations, the right (No. 2) engine experienced a loss of engine power; the associated engine chip light illuminated. The pilot executed a running landing to a nearby landing zone. During the landing, the helicopter encountered rough terrain, which resulted in deformation of the tail boom skin. Postaccident examination of the No. 2 engine revealed that a turbine blade had separated from the 3rd stage turbine wheel. Metallurgical examination of the blade determined that it had failed as a result of high-cycle fatigue probably due to an intermittent vibratory state. The engine manufacturer issued a service bulletin in 2006 and a revised bulletin in 2009 that systematically removed the 3rd stage turbine wheel that was susceptible to this failure mode from the fleet of Model 250 Series II engines. The service bulletin required that the 3rd stage turbine wheel must be replaced at overhaul or if the helicopter experienced an one-engine inoperable (OEI) condition. The turbine wheel had not been replaced, and it could not be determined if the helicopter had experienced an OEI condition.
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
- Loss of engine power (partial) during maneuvering (hover) defining event
- Hard landing during landing
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Turbine section › Fatigue/wear/corrosion
- Environmental issues › Physical environment › Terrain › Rough terrain › Not specified
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 5,579 hours in all; 104 in this make and model; 144 in the last 90 days; 94 in the last 30 days; 5,529 as pilot in command
- Last flight review: July 15, 2011
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 11,827 hours
- Last inspection: 100-hour inspection, January 8, 2012; 92 hours since
- Maximum gross weight: 5,291 lb
- Seats: 7
- Landing gear: fixed
- Engine 1: Allison 250-C20 (turboshaft); 0 hours total
- Engine 2: Allison 250-C20 (turboshaft); 0 hours total
The flight
- Departed from: Makakilo City HI at 1:00 am
- Destination: Makakilo City HI
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: a few clouds at 2,600 ft
- Temperature: 97°F (36°C), dew point 64°F (18°C)
- Altimeter: 30.01 inHg
- Observation at 3:53 am from PHNL, 10 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flig | 1 |
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number WPR12LA125.