# NTSB FTW97LA275: Eichman Aerobat III, N17638, Brownsville, TX, July 20, 1997 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: July 20, 1997, 07:28 local (12:28 UTC) - Place: Brownsville, TX - Coordinates: 25.920045, -97.479583 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=25.9200&lon=-97.4796&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report October 30, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 20286 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW97LA275 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20286/pdf - Page: https://openairdocs.org/ntsb/FTW97LA275 ## Probable cause inadequate design by the pilot/builder/designer. Related factors were: the porpoise that was encountered by the pilot during the takeoff, and the subsequent jammed rudder. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with terrain/water, takeoff - porpoise/pilot-induced oscillation - encountered, pilot in command (contributing factor) - acft/equip,inadequate design, owner/builder (cause) - flight control,rudder - jammed (contributing factor) - aircraft control - not possible - In flight collision with terrain/water, descent - uncontrolled ## Analysis The pilot/builder/designer was attempting to fly the airplane on its maiden test flight. During the takeoff roll, the pilot lifted the airplane's nose wheel off the runway two or three times, then the airplane lifted off the runway and climbed to an altitude approximately one half of the airplane's wingspan. The airplane immediately returned to the runway in a porpoise like motion and lifted off a second time with a hard right roll. The airplane then impacted the runway in an inverted position. Postaccident examination revealed the rudder exhibited crushed areas at the bottom and top. The top crushed area matched dimensionally to the four-belt driven wheel which turned the airplane's propeller. A test pilot reported that during previous high speed taxi runs, conducted in August 1987, he had to apply 'stop-to-stop' elevator stick movements to maintain a steady pitch attitude. A review of the video tape of the taxi tests revealed that the elevator was moving in what appeared to be 'stop-to-stop' movements. The same elevator movements were observed in a video tape of the accident airplane during the attempted takeoff. The test pilot said he believed the airplane 'had some kind of pitch oscillation problem.' ## Factual narrative HISTORY OF FLIGHT On July 20, 1997, at 0728 central daylight time, an Eichman Aerobat III homebuilt experimental airplane, N17638, was substantially damaged when it impacted the ground during initial climb following takeoff from Brownsville/South Padre Island International Airport near Brownsville, Texas. The private pilot, sole occupant in the airplane, was fatally injured. The airplane was being operated by the owner/builder/designer under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the inaugural test flight which was originating at the time of the accident. No flight plan had been filed. Witnesses reported to the Investigator-In-Charge (IIC) that the pilot was attempting to takeoff on its maiden flight. A chase airplane was in a position so that its passenger could make a videotape of the event. The videotape revealed the airplane rolling onto runway 13R and began accelerating. The pilot lifted the airplane's nose wheel off the runway two, or three times, then the airplane lifted off the runway and climbed to an altitude of approximately one half of the airplane's wingspan. The airplane immediately returned to the runway in a porpoise like motion and lifted off a second time with a hard right roll. The airplane impacted the runway in an inverted position. PERSONNEL INFORMATION The pilot was born on July 5, 1913, and his personal flight logbook indicated that he received his private pilot certificate on August 9, 1946. FAA records indicate that the pilot's medical certificate had expired. His last FAA medical exam was dated January 17, 1996, and was valid for 9 months following the month examined. The pilot's medical records indicated a history of heart problems. According to the FAA pathologist at the Civil Aviation Medical Institute (CAMI), "no evidence of physical impairment or incapacitation were found that would have been causal to the accident." The last documented time the pilot flew an airplane, before the accident, was September 15, 1996. AIRCRAFT INFORMATION According to one witness, the pilot/builder/designer had constructed three airplanes in succession: Aerobat I, Aerobat II, and Aerobat III. Aerobat I was started in 1937, and it flew for the first time in 1942. This all metal airplane was a single seat delta wing design with a "T" tail, and the engine (tractor type) was in the front. This airplane accumulated approximately 600 hours before it was damaged and retired. Aerobat II was a two place side-by-side airplane with a wing and empennage almost identical to Aerobat I; it flew a limited but unknown number of times. Witnesses reported to the IIC that the pilot/builder/designer completed Aerobat III in July of 1986 and was issued a Special Airworthiness Certificate in the Experimental Category. This airplane differed from its predecessors in that the engine was moved to the rear of the airplane (pusher type) and the wing was redesigned. On August 2, 1987, Aerobat III was being ground tested by doing several high speed taxis runs when, during one test run the test pilot (not the accident pilot) lifted the nose off the runway and the airplane unintentionally lifted into the air. The test pilot reported to the IIC that he immediately retarded the throttle and pushed the airplane back to the runway. The impact with the runway was sufficient to damage the vertical stabilizer (due to the mass of the engine) and disconnect the nose wheel steering cable. Subsequently, the airplane veered "hard" to the right, collapsing the left main landing gear and damaging the left wing. The test pilot reported to the IIC that during his high speed taxi runs in August 1987, he had to apply "stop-to-stop" elevator stick movements to maintain a steady pitch attitude (with the nose wheel approximately three to four inches off the runway). A review of the video tape of the taxi test run revealed that the elevator was moving in what appeared to be "stop-to-stop" movements. The same elevator movements were observed by the IIC in the video tape of the accident airplane during its attempted takeoff. The test pilot did report to the IIC that he believed the airplane "had some kind of pitch oscillation problem." The pilot/builder/designer repaired the airplane, lowered the powerplant on the vertical stabilizer, and replaced the engine with a Hirth F-23 glider engine. Witnesses stated that the pilot/builder, during separate high-speed taxi tests, damaged the wooden propeller and damaged the empennage near the bottom of the rudder. He subsequently put a hard rubber wheel (approximately 4 inches in diameter) on the empennage at the bottom of the rudder. The dates and details about the airplane's accident in August of 1987 could not be located in the airplane's logbooks. FAA records, dated video tape of the accident, and the test pilot's testimony, were used to document the accident for this report. The pilot documented in the airplane's logbooks that on March 10, 1989, the airplane flew for 15 seconds at 4 to 5 feet above the runway. This could not be substantiated by the IIC; witnesses interviewed indicated they believe that the referred to flight was the first accident flight in August of 1987 when the airplane inadvertently became airborne momentarily. WRECKAGE AND IMPACT INFORMATION The airplane was found intact, inverted, and aligned with the runway on the runway's right side. The right wing was bent at two locations, and the top of the vertical stabilizer was crushed. All three of the wooden propeller blades had been damaged near their tips. The fuselage was crushed upwards where the tail wheel (approximately 4 inches in diameter) was attached to the airplane. The rudder exhibited crushing on its bottom and on its top; the top crushed area matched dimensionally to the four-belt driven wheel which turned the airplane's propeller. The cockpit's canopy had been crushed and occupiable space in the cockpit was compromised. MEDICAL AND PATHOLOGICAL INFORMATION Autopsy and toxicological tests were ordered and performed. The autopsy was performed at the Valley Baptist Medical Center in Harlingen, Texas, on July 21, 1997. Toxicology test results were negative. TESTS AND RESEARCH No airplane documents were found during the investigation which would have enabled weight and balance calculations to be made. ADDITIONAL DATA The airplane was not retained; the pilot's video camera and logbooks were released to the owner's wife on 08/21/97. ## Aircraft - Registration: [N17638](https://openairdocs.org/deregistered/N17638-2014-11-26), registration cancelled 2014-11-26, S/N 1003, built 1985 (OpenAirDocs) - Reported make and model: EICHMAN AEROBAT III (AEROBAT II) - Registry model: [Eichman Ellis V AEROBAT III](https://openairdocs.org/model/eichman-ellis-v-aerobat-iii) (registry code 056125Q) (OpenAirDocs) - Registry engine: [Hirth F20](https://openairdocs.org/engine/hirth-f20) (registry code 33720, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 1003 - Engines: Hirth F-23 40 horsepower reciprocating - Damage: Substantial damage - Flight: Part 91 - Registered owner: Ellis V. Eichman - Airworthiness certificate: Special, Experimental (Special) - Departed: BRO - Airport: BRO, Brownsville/South Padre I, runway 13R, 7,400 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 84; private; airplane ratings: single-engine land; medical: class 3, expired; seat: front; toxicology performed; flight hours: 580 total ## Weather - Conditions: Visual (VMC), Day - Wind: 160° at 4 knots - Visibility: 4 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 79 °F - Altimeter: 29.00 inHg - Observed at: BRO, 1 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 19970720018899A](https://openairdocs.org/incident/19970720018899A), Jul 20, 1997: Amtrlb AEROBAT, Brownsville, TX, Substantial damage, 1 fatal. First test flight lifted porpoised lifted. Rolled. Impacted inverted. (-23) on July 20, 1997, aircraft 17638, mode aerobatt iii, owned, built and operated by… 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.