# NTSB SEA97LA011: Aero Vodochody Aero. Works L-29, N7150A, Tillamook, OR, October 11, 1996 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: October 11, 1996, 16:17 local (23:17 UTC) - Place: Tillamook, OR - Coordinates: 45.459579, -123.710609 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.4596&lon=-123.7106&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 2 fatal - Status: Completed, report August 21, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 42526 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA97LA011 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42526/pdf - Page: https://openairdocs.org/ntsb/SEA97LA011 ## 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 In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, maneuvering - aircraft control - not maintained, pilot in command (cause) - In flight collision with terrain/water, descent - uncontrolled - altitude/clearance - inadequate, pilot in command (contributing factor) ## 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](https://openairdocs.org/deregistered/N7150A-2004-04-07), registration cancelled 2004-04-07, S/N 591318 (OpenAirDocs) - Reported make and model: Aero Vodochody Aero. Works L-29 - Registry model: [Aerovodochody L-29 DELFIN](https://openairdocs.org/model/aerovodochody-l-29-delfin) (registry code 0564310) (OpenAirDocs) - Registry engine: [Pratt & Whitney JT12A series](https://openairdocs.org/engine/pratt-whitney-jt12a-series) (registry code 52056, turbo-jet) (OpenAirDocs) - Category: Airplane - Serial number: 591318 - Engines: P&W J60-5A 3200 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; 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 (OpenAirDocs). - [Accident 19961011036959A](https://openairdocs.org/incident/19961011036959A), Oct 11, 1996: Tillamook, OR, Destroyed, 2 fatal. Photo flight flew into wake of F4F photo target. Lost control rolled. Failed timely pullout from resulting dive. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.