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ASN Wikibase Occurrence # 200898
Last updated: 20 January 2020
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Type:Silhouette image of generic BE35 model; specific model in this crash may look slightly different
Beechcraft V35B Bonanza
Registration: N777PH
C/n / msn: D-9544
Fatalities:Fatalities: 2 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Alva Regional Airport (KAVK), Alva, OK -   United States of America
Phase: Landing
Departure airport:Alva Regional Airport (KAVK)
Destination airport:Alva Regional Airport (KAVK)
Investigating agency: NTSB
The private pilot had recently purchased the Bonanza airplane, which he and an experienced flight instructor were using to conduct his first training flight in a Bonanza. During a visual approach, the engine's left cowling opened. According to the pilot, who initially survived the accident, the flight instructor assumed control of the airplane. Based on video from home surveillance cameras, the descent rate for the approach increased to about 1,000 ft per minute about 100 ft above ground level. About 7 seconds later, the airplane impacted trees and a power line located 1/2 mile from the runway threshold.

The airplane was one of three Bonanza airplanes modified with a Robertson Short Takeoff and Landing (STOL) system. The flight characteristics for this modification included a strong pitch-down force while extending the flap from 15 to 30 position, which is greater than in Bonanzas without this STOL system. The investigation could not determine if the pilot or flight instructor was aware of this unique flight characteristic, which was not described in the STOL certification information.

The pilot had compiled a list of airplane discrepancies, which included "cowling latch - pilot's side rear spring." It is likely a latch for the left engine cowling opened in flight because it was not properly secured during the preflight. The flight instructor and pilot were likely distracted by the open engine cowling and did not expect the strong pitch-down force during flap extension, which resulted in a high descent rate on short final.

Probable Cause: The flight instructor's and pilot's failure to recognize that a high descent rate had developed on short final, likely due to their distraction by an open engine cowling, and the unexpected strong pitch-down force during flap extension due to the installation in the airplane of a Short Takeoff and Landing system.



Accident investigation:
Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year and 6 months
Download report: Final report


Photo: NTSB

Revision history:

05-Nov-2017 05:45 Geno Added
05-Nov-2017 05:49 Geno Updated [Departure airport, Source]
05-Nov-2017 12:08 Iceman 29 Updated [Time, Source, Embed code, Damage, Narrative]
06-Nov-2017 01:14 Geno Updated [Source]
06-Nov-2017 17:17 Geno Updated [Aircraft type, Registration, Cn, Operator, Source]
06-Nov-2017 17:20 Iceman 29 Updated [Aircraft type, Operator, Source]
07-Nov-2017 19:31 gerard57 Updated [Total fatalities, Narrative]
01-Jun-2019 07:29 ASN Update Bot Updated [Time, Operator, Departure airport, Destination airport, Source, Narrative, Accident report, ]
01-Jun-2019 19:14 harro Updated [Aircraft type, Departure airport, Destination airport, Source, Narrative, Photo]

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