SEA07FA263

NTSB accident investigation · Aero Vodochody L-39C · Reno, NV · September 13, 2007

Accident · FatalField investigationFinal report
Date
September 13, 2007, 14:45 local (21:45 UTC)
Place
Reno, NV
Injuries
1 fatal
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N139DKAero Vodochody L-39C
Weather
Visual (VMC) · Day
Status
Completed · report April 30, 2008
Report
Approved by Office Director
Parties
Federal Aviation Administration
FAA report
20070913021399A
Case key
66715

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

The NTSB’s determination of the probable cause, and any contributing factors.

The pilot's encounter with wake turbulence while maneuvering over a race course. Contributing to the accident was the low altitude at which the encounter occurred.

Analysis

The pilot was racing his jet airplane in a scheduled race in a high speed, low-level, racetrack pattern around pylons. Videos were obtained from spectators of the race and reviewed. The videos showed that a Rockwell T-2B (Buckeye) airplane was leading the group of jets, with the accident airplane immediately behind as the group rounded pylon 8. As the accident airplane rounded the pylon, it banked to the left, and then banked to the right. The bank to the right continued through an inverted position as the airplane descended. Upon impact with the ground, the airplane was upright, in a nose low attitude. It is likely that due to the low altitude of the airplane during the accident sequence, there was limited time available for the pilot to recover from the upset. According to the Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25), "All aircraft generate a wake while in flight. This disturbance is caused by a pair of counter-rotating vortices trailing from the wingtips. The vortices from larger aircraft pose problems to encountering aircraft. The wake of these aircraft can impose rolling moments exceeding the roll-control authority of the encountering aircraft."

Factual narrative

The factual narrative846 words

History of flight

On September 13, 2007, at 1445 Pacific daylight time, an Aero Vodochody L-39C, N139DK, collided with terrain while participating in the Reno Air Races at Reno-Stead Airport, Reno, Nevada. The pilot was operating the privately owned airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, was killed; the airplane was substantially damaged. Visual meteorological conditions prevailed and no flight plan was filed. The airplane departed Reno-Stead about 1410.

The pilot was participating in the jet race of the Reno Air Races. The accident airplane had rounded the last pylon, pylon 8, when according to a witness, the airplane was banked to the left as it rounded the pylon. The airplane then rolled to the right and impacted the ground at a high speed.

An additional witness reported that the accident airplane was following another airplane. As the airplanes rounded the pylon, the accident airplane appeared to be lower. The accident airplane then seemed to roll inverted and impacted the ground moments later.

In an interview with the Jet Class Director of Flight Operations, he indicated that the pilot had discussed a passing procedure that was inconsistent with race rules. After the pilot spoke with the Director of Flight Operations, the pilot agreed not to perform the passing procedure. According to the Director of Flight Operations, the pilot flew the race in accordance with the Jet Class rules. The Director of Flight Operations was flying above the race at the time of the accident, and also viewed a video of the event following the accident. Based on his experience, it appeared that the pilot may have inadvertently entered the wake turbulence from the T-2B Buckeye and was unable to regain control of the airplane prior to its impact with the ground. Additionally, the Director of Flight Operations indicated that all pilots are given training in wake turbulence avoidance procedures during the Reno Pylon Racing Seminar.

Personnel information

The 47 year old pilot held a private pilot certificate with an instrument rating and was certified to fly single engine land and sea airplanes. The pilot had about 1,500 hours total time, with 150 hours in the accident airplane. He had flown the accident airplane about 15 hours within the last 90 days.

The pilot attended the Reno Pylon Racing Seminar in 2006, and he had competed in the jet races in 2006 and 2007. According to the check pilot, the pilot flew well during the racing seminar and no problems were noted.

Aircraft information

The airplane was issued an experimental Special Airworthiness Certificate on February 8, 2006, for exhibition. A Ukrainian Progress A1-25TL engine powered the airplane. The last inspection of the airplane was on July 11, 2007, at a total time of 961.1 hours. According to the maintenance personnel that worked on the airplane, an additional 15 hours had accrued on the airplane since the inspection.

Wreckage and impact information

The wreckage debris field ran generally parallel to runway 8/26 at Reno-Stead and was approximately 705 yards in length. The first identified point of contact consisted of two distinct shapes; one was a large disruption to the soil and spanned outward to the remainder of the debris field and to its left was a mark in the soft soil, rectangular and similar in size and shape to the leading edge of a wing. There was no similar rectangular shape on the right side of the large disruption. The debris field was on a magnetic heading of 240 degrees. Approximately 100 yards into the debris field, the smell of fuel was evident and areas of burn were present.

From the initial soil disruption, the debris field consisted of many small pieces of debris, with multiple large sections. All control surfaces, or portions of them, were identified in the debris field. The engine was separated from the airframe structure during the accident sequence and was the last identified piece of debris within the field. The outer case had been torn from the engine and located by investigators earlier in the debris field. The turbine blades were bent opposite the direction of rotation and portions of the blade tip material were missing.

Additional information

Videos were obtained from spectators of the Reno Air Races and viewed. The videos showed that a Rockwell T-2B (Buckeye) airplane was leading the group, with the accident airplane behind him. When they rounded pylon 8, the accident airplane was behind the Buckeye. As the accident airplane rounded the pylon, it banked to the left, and then banked to the right. The bank to the right continued through an inverted position as the airplane descended. Upon impact with the ground, the airplane was upright, in a nose low attitude.

According to the Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25), "All aircraft generate a wake while in flight. This disturbance is caused by a pair of counter-rotating vortices trailing from the wingtips. The vortices from larger aircraft pose problems to encountering aircraft. The wake of these aircraft can impose rolling moments exceeding the roll-control authority of the encountering aircraft."

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
Low altitude flight/maneuver - performedPilot in commandFactor
Wake turbulence - encounteredPilot in commandCause
Aircraft control - not possiblePilot in commandCause
In flight collision with terrain/waterDescent - uncontrolled
Terrain condition - ground

Aircraft

Registration
N139DK
Reported as
Aero Vodochody L-39C
Category
Airplane
Serial number
934874
Airframe hours
961
Engine
Ukraine Progress A1-25-TL, 3,800 lbs thrust, turbo fan
Damage
Substantial damage
Fire
On-Ground
Flight
Air race/show · Part 91
Registered owner
Bradley Morehouse
Airworthiness certificate
Special, Experimental (Special)
Last inspection
100 hour · July 1, 2007 · 15 hours before
Departed
4SD · Reno/Stead, NV
Airport
4SD · Reno Stead Airport

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
47
Injuries
Fatal
Certificate
Private
Airplane ratings
Single-engine land
Instrument ratings
Airplane
Medical
Class 3, With waivers/limitations
Last flight review
December 1, 2006
Seat
Front
Toxicology
Performed
Flight hours
1,500 total · 150 in this make and model

Weather

Conditions
Visual (VMC) · Day
Wind
260° at 13 knots, gusting 20
Visibility
10 statute miles
Lowest ceiling
None
Temperature
81 °F, dew point 12 °F
Altimeter
29.96 inHg
Observed at
RNO, 12 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.