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| Date: | Sunday 10 August 1980 |
| Time: | 09:43 LT |
| Type: |  Aero Commander 685 |
| Owner/operator: | Kyoritsu Koku Satsueiki |
| Registration: | JA5231 |
| MSN: | 12056 |
| Fatalities: | Fatalities: 2 / Occupants: 2 |
| Other fatalities: | 0 |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | Tokyo -
 Japan
|
| Phase: | Take off |
| Nature: | Unknown |
| Departure airport: | RJTF |
| Investigating agency: | AAIC |
| Confidence Rating: |  Accident investigation report completed and information captured |
On August 10, 1980, Aero Commander 685, registration JA5231, operated by Kyoritsu Aerial Survey Co., Ltd., with a pilot and one other person on board for an aerial survey, crashed and was heavily damaged at approximately 09:43 JST on the grounds of Chofu Municipal Chofu Junior High School (4 Chome-17 Fujimicho, Chofu, Tokyo) immediately after taking off from the Chofu Out-of-Area Landing Site (hereinafter referred to as "Chofu Airport").
There was no fire as a result of this accident, but all occupants died.
Cause
It is presumed that this accident occurred because, at a low speed and low altitude immediately after liftoff, the aircraft suddenly lost power in its left engine. Subsequently, flight continued without the landing gear and flaps being retracted, or the propeller feathered, leading to a decrease in speed, a stall, and the eventual crash.
Furthermore, it is presumed that the loss of power in the left engine was due to the failure of the engine-driven fuel pump, caused by the shearing of the fuse section of the pump's drive coupling.
Accident investigation:
 |
|
Sources:
https://jtsb.mlit.go.jp/aircraft/rep-acci/56-5-JA5231.pdf
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 27-Sep-2008 01:00 | ASN archive | Added |
| 16-Jul-2025 12:22 | HanayoPlus | Updated [Time, Cn, Phase, Departure airport, Source, Damage, Narrative, ] |
| 16-Jul-2025 12:22 | ASN | Updated [Accident report, ] |
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