FTW03LA091

NTSB accident investigation · Gilbertson Zodiac CH601HDS · Grandfield, OK · February 1, 2003

Accident · No injuriesLimited investigationFinal report
Date
February 1, 2003, 13:00 local (19:00 UTC)
Place
Grandfield, OK
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N474BGGilbertson Zodiac CH601HDS
Weather
Visual (VMC) · Day
Status
Completed · report May 13, 2003
Report
Approved by Office Director
Parties
FAA FSDO
FAA report
20030201000669A
Case key
56426

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

The loss of engine power for an undetermined reason. Contributing factors were the lack of suitable terrain for the forced landing and the unfavorable wind.

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 engine powerCruise
Reason for occurrence undeterminedCause
Forced landingDescent - emergency
On ground/water encounter with terrain/waterEmergency landing
Terrain condition - none suitableFactor
Terrain condition - high vegetation
Weather condition - unfavorable windFactor

Analysis

During a test flight on the morning of the accident, the engine was running rough; however, the pilot landed the airplane without further incident. The pilot removed the carburetor screen, cleaned the debris from the screen, and reinstalled the screen. During the accident flight, the oil and water temperature indicated 205-210 degrees, and the flight was returning to the airport. At an airspeed of 70 knots and an altitude of 500 feet agl, there was a total loss of engine power. The pilot performed the emergency landing procedures; however, he was not able to turn the airplane into the wind due to an unsafe landing area east of the airport traffic pattern for the runway. The pilot landed the airplane with a right quartering tailwind (25 knots, gusts 30 knots) in a field. During the landing roll, the nose landing gear struck a berm, the nose landing gear collapsed, and the airplane structure twisted as the airplane came to rest. The reason for the loss of engine power was not determined. The pilot reported the winds were from the southwest at 25 knots with gust to 30 knots. The airplane had accumulated 27.6 hours of the required 40 hours of flight time under the operating limitations for the homebuilt airplane.

Factual narrative

On February 1, 2003, approximately 1300 central standard time, a Gilbertson Zodiac CH601HDS experimental airplane, N474BG, struck a berm during a forced landing following a total loss of engine power near Grandfield, Oklahoma. The airplane was built, owned, and operated by the pilot under 14 Code of Federal Regulations (CFR) Part 91. The airline transport pilot, sole occupant of the airplane, was not injured, and the airplane sustained substantial damage. Visual meteorological conditions prevailed for the local flight, and a flight plan was not filed. The test flight originated from Chattanooga Sky Harbor Airport (92F) at Chattanooga, Oklahoma, approximately 1240.

The 5,043 hour pilot reported to the FAA inspector that during a flight that morning, the 73 horsepower Subaru automotive engine was running rough; however, he landed the airplane without further incident. The carburetor screen was removed, cleaned of debris, and reinstalled by the pilot.

On the Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2, the pilot reported that during the accident flight, the oil and water temperature indicated 205-210 degrees, and the pilot elected to return to the airport at an initial altitude of 700 feet agl. At an airspeed of 70 knots and an altitude of 500 feet agl, there was a total loss of engine power. The pilot performed the emergency landing procedures. The pilot was not able to turn the airplane into the wind due to an unsafe landing area east of the airport traffic pattern for runway 17. The pilot attempted a 270 degree turn to a landing area; however, due to the decreasing altitude and airspeed (55 knots) of the airplane, he was not able to compete the turn. The pilot landed the airplane in a field with a right quartering tailwind. During the landing roll, the nose landing gear struck a berm, the nose landing gear collapsed, and the airplane came to rest 110 feet from the initial impact point in the field. The pilot reported the winds were from the southwest at 25 knots, with gust to 30 knots.

The FAA inspector reported that during the impact sequence, the airplane structure twisted, and the firewall and all components forward of the firewall separated from the airplane. The integrity of the fuel tank was compromised. The airplane had accumulated 27.6 hours of the required 40 hours of flight time under the operating limitations for the homebuilt airplane.

Aircraft

Registration
N474BG
Reported as
Gilbertson Zodiac CH601HDS
Category
Airplane, amateur-built
Serial number
63628
Airframe hours
28
Engine
Subaru EA81, 73 horsepower, reciprocating
Damage
Substantial damage
Flight
Flight test · Part 91
Registered owner
Keith G. Gilbertson
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Condition · August 31, 2002 · 31 hours before
Departed
92F · Chattanooga, OK
Destination
92F · Chattanooga, OK
Airport
92F · Chattanooga Sky Harbor, runway 17, 3,400 × 60 ft, asphalt

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
53
Injuries
None
Certificate
Airline transport
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Helicopter, Airplane
Medical
Class 2, Valid Medical--no waivers/lim.
Last flight review
October 5, 2001
Seat
Left
Flight hours
5,043 total · 28 in this make and model · 3,117 as pilot in command · 67 in the last 90 days · 21 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
325° at 25 knots, gusting 30
Visibility
10 statute miles
Lowest ceiling
None
Temperature
70 °F

Docket · 1

The files NTSB released with the investigation on March 26, 2003, on NTSB’s docket system: statements, records, photos and specialists’ reports. 606 KB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.