LAX98LA093 · Boeing MD600N
Boeing MD600N · Accident: hard landing
From FFZ to an unrecorded destination
Event
- NTSB case
- LAX98LA093
- 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
- 0
- 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
- General aviation
- 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
Boeing MD600N
- Aircraft type
- Boeing MD600
- 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
- N9204D
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From FFZTo not recorded
- 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
- Part 91: General Aviation
- 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
- Landing · emergency landing after takeoff
- First occurrenceThe 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
- Hard landing
- 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 performance, landing capability › Exceeded
- Autorotation › Not possible
- Production/design personnel › Height/velocity curve, exceeded
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
While in the process of verifying a height/velocity performance data point, the pilot entered an autorotation at takeoff power and maximum gross weight. The onboard telemetry revealed that the pilot reduced the throttle to flight idle at the entry point but that the remaining momentum caused the aircraft to accelerate and climb. During the descent, the main rotor rpm decayed and an excessive vertical sink rate developed. The aircraft landed hard at the intended touchdown point. The aircraft was hover-taxied from the landing area and a normal shutdown was completed. The test pilot reported that the height/velocity data point was outside the aircraft's performance capabilities.
Probable cause
the attempt by flight test engineers to verify a height/velocity data point that was subsequently shown to be outside the aircraft's performance capabilities.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX98LA093
- Event ID
- 20001211X09574
- Case number
- LAX98LA093
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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: f263d553b216819f92c056ee65749331fd5fd5102d66d89e1b860977aae6958d; retrieved 2026-09-22T18:03:20.002Z.