Cessna 320 accident near Mammoth Lakes, California, April 28, 1996
On April 28, 1996 at about 8:45 pm local time, a Cessna 320, registered N5752X, was substantially damaged in an accident near Mammoth Lakes, California (Mammoth Lakes airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 3 people were on board or involved. The weather was visual conditions (good weather).
Preview. This page is not yet listed for search engines.
The NTSB's probable cause their words, unchanged
the partial failure of the right engine turbocharger wastegate butterfly valve to fully close due to mechanical binding and the low setting of its associated absolute pressure controller. A related factor was the high density altitude which reduced the engine's ability to produce adequate manifold pressure.
Source: NTSB aviation accident database, copy made September 29, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 28, 1996 · about 8:45 pm local time
- Place
- Mammoth Lakes, California · Mammoth Lakes · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 320 · all 320s on the register
- Registration
- N5752X · registry record · serial 320-0052
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot performed a static engine run-up, and with no discrepancies noted, he commenced the takeoff. Upon reaching between 25 and 50 feet above the runway during the initial climb, the normal 35 inches of manifold pressure (MP) was observed being produced by the left engine. However, the right engine only produced between 18 and 20 inches of MP. The airplane veered right and settled into the rough/uneven terrain near the airport. The airport's elevation is 7,128 feet mean sea level, and the calculated density altitude was over 8,200 feet. An examination of the right engine's turbocharger assembly revealed the absolute pressure controller was set lower than the manufacturer's specifications required. Also, the wastegate butterfly valve was mechanically binding in its housing and would not fully close.
The NTSB's narratives can run to many pages; this is the opening. Read the full report at the NTSB.
About this page
Everything above comes from the NTSB's public accident database and is rewritten in plain English only where the NTSB used codes; the probable cause and narrative are the NTSB's own words. 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 LAX96LA180.