# NTSB FTW03LA091: Gilbertson Zodiac CH601HDS, N474BG, Grandfield, OK, February 1, 2003 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: February 1, 2003, 13:00 local (19:00 UTC) - Place: Grandfield, OK - Coordinates: 34.237777, -98.741943 - Nearby events: https://openairdocs.org/map.md?lat=34.2378&lon=-98.7419&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 13, 2003 - Report: Approved by Office Director - Parties: FAA FSDO - NTSB case key (mKey): 56426 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW03LA091 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/56426/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=56426 - Page: https://openairdocs.org/ntsb/FTW03LA091 ## 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 In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, cruise - reason for occurrence undetermined (cause) - Forced landing, descent - emergency - On ground/water encounter with terrain/water, emergency landing - terrain condition - none suitable (contributing factor) - terrain condition - high vegetation - weather condition - unfavorable wind (contributing factor) ## 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](https://openairdocs.org/aircraft/N474BG), registered now, S/N 63628, built 2002 (OpenAirDocs) - Reported make and model: Gilbertson Zodiac CH601HDS - Registry model: [Gilbertson Keith G ZODIAC CH 601HDS](https://openairdocs.org/model/gilbertson-keith-g-zodiac-ch-601hds) (registry code 05614P5) (OpenAirDocs) - Registry engine: [Subaru ALL MDLS A/B](https://openairdocs.org/engine/subaru-all-mdls-a-b) (registry code 59050, 4 cycle) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 63628 - Airframe hours: 28 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: none; 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 ## 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 20030201000669A](https://openairdocs.org/incident/20030201000669A), Feb 1, 2003: Amtr ZODIAC, Grandville, OK, Substantial damage. (.19) On February 1, 2003, approximately 1235 central standard time, a gilbertson Zodiac CH601HDS, experimental airplane, N474BG, struck a terrace during a… ## Docket (1 files) The files NTSB released with the investigation on March 26, 2003, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=56426. 606 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 606 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40382470&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF 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.