# NTSB CHI08LA123: Dickenson Bathtub, N538, Broadhead, WI, May 5, 2008 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: May 5, 2008, 17:00 local (22:00 UTC) - Place: Broadhead, WI - Coordinates: 42.609748, -89.370857 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.6097&lon=-89.3709&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern final: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report July 28, 2009 - Report: Approved by Office Director - Parties: FAA-Milwaukee FSDO - NTSB case key (mKey): 68004 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI08LA123 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68004/pdf - Page: https://openairdocs.org/ntsb/CHI08LA123 ## Probable cause The pilot's failure to maintain adequate airspeed during approach, which resulted in an aerodynamic stall. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Dickenson BATHTUB, 1 case](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=056199R), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Dickenson BATHTUB, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=056199R), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern final: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) (defining event); cases with it: [Dickenson BATHTUB, 1 case](https://openairdocs.org/ntsb-events/241/sequence.md?model=056199R), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Approach-VFR pattern final: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Dickenson BATHTUB, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=056199R), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The airplane was destroyed when it impacted terrain following a loss of control on final approach to land. The flight was the pilot's first flight in the airplane. A witness reported seeing the airplane as it turned from a left base leg of the airport traffic pattern to final approach. The witness reported that the airplane's bank angle increased during the turn to correct for wind drift. It then stalled and entered a spin. Another witness also reported that he believed the accident was the result of a stall/spin. Neither witness reported hearing any engine malfunctions. No preimpact mechanical deficiencies were found with the airplane. ## Factual narrative HISTORY OF FLIGHT On May 5, 2008, about 1700 central daylight time, an amateur-built Dickenson Bathtub, N538, was destroyed when it impacted terrain following a loss of control on final approach to land on runway 03 at the Broadhead Airport, Broadhead, Wisconsin. The private pilot was fatally injured. Visual meteorological conditions prevailed for the 14 CFR Part 91 flight. No flight plan was filed. The local flight originated at an unconfirmed time. A witness reported seeing the airplane during its approach to the airport. He stated that as the airplane made a left turn from the base leg of the approach to the final approach he noticed that the wind was drifting the airplane toward some houses. He stated that he saw the airplane's turn tighten, and then the airplane entered a stall/spin. It subsequently impacted the ground. He estimated that the airplane's altitude was about 300 feet above the ground when it entered the spin. He stated that he heard no engine malfunctions. He stated that the accident flight was the pilot's first flight in the airplane. Another witness who has been a certified flight instructor since 1982 reported that he believed the accident was the result of a stall/spin. He noted that the engine was running fine and seemed "ok" all the way to the ground. PERSONNEL INFORMATION The pilot, age 77, held a Federal Aviation Administration private pilot certificate with single engine land and sea ratings. He also held a third class medical certificate issued January 31, 2008. The medical certificate listed a limitation that the pilot have glasses available for near vision. FAA records indicate that the pilot had accumulated a total of 1,400 flight hours as of the date of his most recent medical examination. No further pilot flight records were obtained. AIRCRAFT INFORMATION The airplane was an amateur-built replica of a 1924 Dormoy Bathtub. It had a single strut braced fabric covered parasol mounted wing. The fuselage consisted of an open pilot enclosure with a single tubular structure running along the bottom of the fuselage and aft to the tail surfaces. Two additional tubular supports ran from the trailing edge of the wing to the top of the vertical tail. METEOROLOGICAL INFORMATION At 1656, the weather conditions at the Monroe Municipal Airport, about 9 miles west of the accident site, were: Wind 260 degrees at 13 knots gusting to 16 knots; visibility 10 miles; scattered clouds at 10,000 feet; temperature 22 degrees Celsius; dew point -4 degrees Celsius; altimeter setting 19.98 inches of mercury. AIRPORT INFORMATION The Broadhead Airport was a privately owned airport and had 3 turf runways. The runway in use at the time of the accident was Runway 03 which was 1,480 feet long and 100 feet wide. WRECKAGE AND IMPACT INFORMATION The airplane came to rest in a nose low position. The aft fuselage tubing structure was bent forward and upward in relation to the fuselage tub. The right wing and right landing gear were crushed rearward. The left wing remained intact. Examination of the airplane did not reveal any pre-existing deficiencies. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy of the pilot was performed by the University of Wisconsin, School of Medicine. The report stated that the pilot perished as a result of the aircraft collision. A Final Forensic Toxicology Fatal Accident Report listed Naproxen detected in the pilot's urine. ## Aircraft - Registration: [N538](https://openairdocs.org/aircraft/N538), registered now, S/N 101, built 2007 (OpenAirDocs) - Reported make and model: DICKENSON BATHTUB - Registry model: [Dickenson BATHTUB](https://openairdocs.org/model/dickenson-bathtub) (registry code 056199R) (OpenAirDocs) - Registry engine: [Heath Avn B4](https://openairdocs.org/engine/heath-avn-b4) (registry code 32501, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 101 - Airframe hours: 1 - Engines: HEATH AVN B4 25 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, August 31, 2007, 1 hours before - Departed: C37, Broadhead, WI - Airport: C37, Broadhead Airport, runway 03, 1,480 × 100 ft, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 77; injuries: fatal; private; airplane ratings: single-engine land, single-engine sea; medical: class 3, with waivers/limitations; seat: center; toxicology performed; flight hours: 1,400 total, 1 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 13 knots, gusting 16 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 25 °F - Altimeter: 30.00 inHg - Observed at: EFT, 9 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 20080505835559A](https://openairdocs.org/incident/20080505835559A), May 5, 2008: Dicken BATHTUB, Brodhead, WI, Destroyed, 1 fatal. (-23) On may 5, 2008, at approximately 1700 cdlt the pilot of an amateur built aircraft, dickerson Bathtub, on final approach to runway 03 at broadhead… 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.