WPR10TA025 · McDonnell Douglas Helicopter 500N
City of Huntington Beach McDonnell Douglas Helicopter 500N · Accident: hard landing
From H.B.P.D. Heliport (CL65) to Los Alamitos Army Air Field (KSLI)
Narrative check · The NTSB narrative appears to contradict this record's departure or destination. Values are shown as recorded, not corrected; compare with the narrative.
Event
- NTSB case
- WPR10TA025
- 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
- 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
McDonnell Douglas Helicopter 500N
- Aircraft type
- McDonnell Douglas 500
- 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
- N521HB
- Operator
- City of Huntington Beach
- Onboard fatalities
- Unknown
- Route Narrative disagrees
- From H.B.P.D. Heliport (CL65), Huntington Beach, CATo Los Alamitos Army Air Field (KSLI), Los Alamitos, CA
- 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 · flare/touchdown
- 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
- 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 › Aircraft oper/perf/capability
- Personnel issues › Action/decision
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The certified flight instructor (CFI) and the pilot he was instructing were practicing emergency procedures, in particular, power recovery autorotations. At 700 feet above ground level (agl), the CFI rolled the throttle off (idle) and entered the autorotation. At 50 feet agl he rolled the throttle on late, realized the ground was rapidly approaching, and decided to perform a running landing. The pilot reported that he inadvertently applied partial throttle, which did not allow the engine to regain full power. With the throttle positioned at 25 percent, the rotor rpm decayed, and when the helicopter contacted the ground, a rotor blade dipped down and struck the tail boom. The pilot stated that the helicopter and engine had no mechanical failures or malfunctions during the flight.
Probable cause
The flight instructor's delayed remedial action during the instructional autorotative landing, which resulted in a failure to maintain an adequate rotor rpm to avoid a hard landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR10TA025
- Event ID
- 20091020X30424
- Case number
- WPR10TA025
- 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, coordinates. 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: df3ae8204c7246cbdd0cbb220e2b22aef682208d121afc51ac618c819250a4f5; retrieved 2026-09-15T13:25:41.027Z.