- Date
- May 1, 1991, 06:53 local (12:53 UTC)
- Place
- Bennett, CO
- Injuries
- 1 fatal
- Damage
- Destroyed
- Phase of flight
- Enroute
- Aircraft
- N7407LPiper PA-31B-310
- Weather
- Visual (VMC) · Day
- Status
- Completed · report October 2, 1992
- Report
- Approved by Office Director
- FAA report
- 19910501013939A
- Case key
- 18020
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
In-flight separation of the left engine cowl assembly that was not properly latched, and failure of the pilot to maintain minimum control speed, which resulted in his loss of aircraft control. Factors related to the accident were: an inadequate preflight inspection, inadequate markings/alignment indications to assure that the cowl fasteners were locked, and an insufficiently defined procedure in the flight manual for checking the cowl fasteners.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
Shortly after takeoff, while climbing to cruise altitude, the pilot reported the left engine cowl assembly had come off. Witnesses observed the airplane at low altitude & noted that it was 'yawing, sputtering, and rocking back and forth.' They indicated the left engine was not running & that the airplane banked sharply to the right & disappeared behind trees before crashing. An investigation revealed the left propeller had not been feathered. The left engine cowling was found 1.8 miles from the accident site. The three primary (eyebolt) cowl fasterers on the outboard side of the left upper cowl were found unlocked & seven other cowl attaching studs (screws) were missing. The cowling had been removed 16 days before the accident to install an oil/air separator. This was the first flight since that work was performed. The mechanic, who did the work, said he noted several cowl stud fasteners were missing & that he had notified the pilot. The pilot was reported to have replied that he had some fasteners & would take care of the problem.
Aircraft
- Registration
- N7407L
- Reported as
- Piper PA-31B-310
- Category
- Airplane
- Serial number
- 31-790
- Engine
- Lycoming TIO-540-A2B, 310 horsepower, reciprocating
- Damage
- Destroyed
- Fire
- On-Ground
- Flight
- Business · Part 91
- Operator
- John Westbrook, doing business as John Westbrook, Inc.
- Departed
- APA · Englewood, CO
- Destination
- DSM · Des Moines, IA
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 45
- Certificate
- Private
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 3, Valid Medical--no waivers/lim.
- Toxicology
- Performed
- Flight hours
- 6,200 total · 6,094 as pilot in command · 150 in the last 90 days
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 150° at 3 knots
- Visibility
- 50 statute miles
- Lowest ceiling
- None
- Temperature
- -0 °F, dew point -0 °F
- Observed at
- APA, 21 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.