Hyannis Air Services Cessna 402C incident
Cessna 402C · Incident: landing gear collapse
From Cape Cod Gateway Airport (HYA) to Nantucket Memorial Airport (ACK)
Event
- NTSB case
- ERA09IA267
- 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
- Incident
- 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
- Charter & commuter
- 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
Cessna 402C
- Aircraft type
- Cessna 402
- Category
- Airplane
- 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
- N769EA
- Operator
- Hyannis Air Services
- Onboard fatalities
- Unknown
- Route
- From Cape Cod Gateway Airport (HYA), Hyannis, MATo Nantucket Memorial Airport (ACK), Nantucket, MA
- 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 135: Air Taxi & Commuter
- 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
- Landing gear collapse
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Aircraft › Aircraft systems
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot lowered the landing gear and the left main landing gear would not extend. He recycled the landing gear and completed the checklist items with negative results. The left landing gear subsequently collapsed during the landing roll out. A landing gear retraction test was conducted and the failure was duplicated. The extend inlet port for the up lock actuator was then removed for inspection. A small ball bearing was in the wrong position with respect to the larger ball bearing. The smaller ball bearing jumped the larger ball bearing causing a blockage. The up lock actuator and the main gear actuator were removed and examined at an authorized repair facility. Disassembly of the up lock actuator confirmed the initial finding, and revealed that the smaller ball bearing was too small. The main gear actuator was tested and was within manual limits. The operator stated that the up lock actuators are a condition item. The mechanic who performed the last inspection stated that he did not replace any bearings. The investigation could not determine who replaced the bearings or when they were replaced.
Probable cause
Installation of an improper bearing in the landing gear actuator.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ERA09IA267
- Event ID
- 20090427X02120
- Case number
- ERA09IA267
- 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: 26f2f7ed15da2fafd4a1b986d8faf372cdaa4388c970daad1f23716de319e95c; retrieved 2026-09-15T10:59:12.585Z.