SEA97LA011

NTSB accident investigation · Aero Vodochody Aero. Works L-29 · Tillamook, OR · October 11, 1996

Accident · FatalLimited investigationFinal report
Date
October 11, 1996, 16:17 local (23:17 UTC)
Place
Tillamook, OR
Injuries
2 fatal
Damage
Destroyed
Phase of flight
Maneuvering
Aircraft
N7150AAero Vodochody Aero. Works L-29
Weather
Visual (VMC) · Day
Status
Completed · report August 21, 1997
Report
Approved by Office Director
FAA report
19961011036959A
Case key
42526

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

failure of the pilot to maintain control of the aircraft, while maneuvering behind an F4F aircraft. The lack of altitude for a recovery was a related factor.

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.

Loss of control - in flightManeuvering
Aircraft control - not maintainedPilot in commandCause
In flight collision with terrain/waterDescent - uncontrolled
Altitude/clearance - inadequatePilot in commandFactor

Analysis

The Checkoslovakian manufactured Aero Vodochody L-29 jet trainer collided with terrain following a loss of control while maneuvering at low altitude. Before the accident, the aircraft was maneuvering into position to photograph an F4F Wildcat aircraft. Witnesses reported that the aircraft took off and maneuvered to overtake the Wildcat. They stated that as the L-29 crossed behind the F4F's flight path, it rolled to the right, approximately 1-1/4 turns. Reportedly, the L-29's nose pitched up during the occurrence, then dropped to an extremely nose-low position. The aircraft subsequently impacted the ground in a near level attitude with a steep flight path angle. The witnesses reported that the sequence took place at an estimated airspeed between 120 and 150 knots and about 500 feet above ground level. The witnesses also reported that the two aircraft did not collide. A guide to world military aircraft gives the airplane's flaps-down stall speed as 81 MPH (70 knots) at 7165 pounds gross weight. One witness stated the pilot had performed a 'barrel' roll type of maneuver; the witness believed this was an intentional maneuver to slow down, as he was overtaking the F4f. The investigation did not determine whether the aircraft had encountered wake turbulence, or whether it had stalled and/or dished out during the maneuver.

Factual narrative

On October 11, 1996, approximately 1617 Pacific daylight time, an Aero Vodochody L-29 Delfin, N7150A, registered to the Erickson Group Ltd. of Beaverton, Oregon, collided with terrain following a loss of control while maneuvering at low altitude in the vicinity of Tillamook Airport, Tillamook, Oregon. The commercial pilot and a passenger were fatally injured, and the experimental-category airplane, a Czechoslovakian-manufactured two-seat military jet trainer retrofitted with a Pratt & Whitney J60-5 engine, was destroyed. The 14 CFR 91 flight was planned as a local flight out of Tillamook. Visual meteorological conditions prevailed and no flight plan had been filed.

A representative of the operator stated that the passenger was a photojournalist for an aviation publication and that the flight was being conducted as a photographic mission for the passenger. At the time of the accident, the aircraft was maneuvering into position to photograph an F4F Wildcat aircraft. Witnesses reported that the aircraft took off and maneuvered to overtake the Wildcat. They stated that as the L-29 crossed behind the F4F's flight path, it initiated a roll to the right, rolling approximately 1 1/4 turns, and that the L-29's nose then pitched up, then dropped to an extremely nose-low position, and that the aircraft subsequently impacted the ground in a near level attitude with a steep flight path angle. The witnesses reported that the sequence took place at an estimated airspeed between 120 and 150 knots and about 500 feet above ground level. The witnesses also reported that the two aircraft did not collide. A guide to world military trainers published in the magazine of the Air Force Association (John W.R. Taylor & Kenneth Munson, "World Gallery of Trainers", Air Force Magazine, December 1995) gives the L-29's flaps-down stall speed as 81 MPH (70 knots) at 7,165 pounds gross weight.

FAA investigators conducted an on-site examination of the aircraft wreckage on the day after the crash. They reported that they did not find any evidence of malfunction in either the airframe or the engine.

The operator, Erickson Group Ltd., failed to return a completed NTSB Form 6120.1/2, Pilot/Operator Aircraft Accident Report.

Aircraft

Registration
N7150A
Reported as
Aero Vodochody Aero. Works L-29
Category
Airplane
Serial number
591318
Engine
P&W J60-5A, 3,200 lbs thrust, turbo jet
Damage
Destroyed
Fire
On-Ground
Flight
Part 91
Registered owner
Erickson Group Ltd.
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Annual · April 10, 1996
Departed
S47

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
Commercial
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--no waivers/lim.
Seat
Front
Toxicology
Performed
Flight hours
10,840 total · 8,195 as pilot in command

Weather

Conditions
Visual (VMC) · Day
Wind
230° at 7 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
59 °F, dew point 46 °F
Altimeter
30.00 inHg
Observed at
AST, 44 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.