- Date
- December 15, 1993, 16:00 local (23:00 UTC)
- Place
- Erie, CO
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N360HPEbershoff Steen Skybolt
- Weather
- Visual (VMC) · Day
- Status
- Completed · report September 13, 1994
- Report
- Approved by Office Director
- FAA report
- 19931215047419A
- Case key
- 18981
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
Was flutter of the flight controls.
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
During a post-maintenance test flight, the pilot accelerated the highly modified aerobatic airplane to 190 mph. Immediately, the flight controls began to flutter. The pilot raised the nose, slowed the airplane, and landed uneventfully. Post-accident examination revealed a fractured lower right aft wing spar, and a lower left aileron actuator that had buckled in compression overload.
Factual narrative
On December 15, 1993, approximately 1600 mountain standard time, N360HP, an Ebershoff Steen Skybolt, sustained substantial damage in flight near Erie, Colorado. The pilot was not injured. Visual meteorological conditions prevailed for the test flight.
The following is based on the pilot/operator report and a subsequent interview. Maintenance had recently been performed on the engine and the pilot was test flying the highly modified aerobatic airplane prior to it being returned to service. He lowered the nose 45 degrees below the horizon and accelerated to 190 MPH. Immediately, the flight controls began to flutter. He reduced power, raised the nose, and slowed the airplane. The pilot flew back to Jeffco Airport in Broomfield, Colorado, and landed uneventfully. Post-accident examination revealed a fractured lower right aft wing spar, torn fabric on the lower left aileron, and a broken actuator. According to a University of Denver metallurgist, the actuator "had buckled in compression overload."
Aircraft
- Registration
- N360HP
- Reported as
- Ebershoff Steen Skybolt (STEEN SKYB)
- Category
- Airplane, amateur-built
- Serial number
- DE1002
- Airframe hours
- 1,100
- Engine
- Lycoming IO-540-K1AS, 350 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Part 91
- Registered owner
- Ebershoff Airplane Co., Inc.
- Airworthiness certificate
- Special, Experimental (Special)
- Last inspection
- Annual · December 14, 1993 · 1 hours before
- Departed
- BJC · Broomfield, CO
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 53
- Certificates
- Commercial, Private
- Airplane ratings
- Single-engine land
- Medical
- Class 2, Valid Medical--w/ waivers/lim
- Seat
- Rear
- Flight hours
- 2,500 total · 1,500 in this make and model · 2,500 as pilot in command · 25 in the last 90 days
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 180° at 4 knots
- Visibility
- 50 statute miles
- Lowest ceiling
- None
- Temperature
- 50 °F
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.