# NTSB CHI90LA031: Helio H-391B, N8750R, Plainwell, MI, November 20, 1989 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: November 20, 1989, 13:00 local (18:00 UTC) - Place: Plainwell, MI - Coordinates: 42.439052, -85.639724 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.4391&lon=-85.6397&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 25, 1991 - Report: Approved by Office Director - NTSB case key (mKey): 14594 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI90LA031 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14594/pdf - Page: https://openairdocs.org/ntsb/CHI90LA031 ## Probable cause FAILURE OF THE CROSSWIND LANDING GEAR SYSTEM TO ENGAGE ON THE LEFT MAIN GEAR DUE TO IMPROPER RIGGING ADJUSTMENT BY MAINTENANCE PERSONNEL. FACTORS RELATED TO THE ACCIDENT WERE: UNFAVORABLE WIND CONDITIONS (GUSTS AND QUARTERING CROSSWIND) AND SOFT TERRAIN IN THE DITCH. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - flare/touchdown - landing gear,gear locking mechanism - improper (cause) - maintenance,adjustment - improper, other maintenance personnel (cause) - Loss of control - on ground/water, landing - roll - weather condition - crosswind (contributing factor) - weather condition - gusts (contributing factor) - directional control - not possible - ground loop/swerve - uncontrolled - On ground/water encounter with terrain/water, landing - roll - terrain condition - ditch (contributing factor) - terrain condition - soft (contributing factor) - Main gear collapsed, landing - landing gear,main gear - overload ## Analysis THE PILOT STATED THAT DURING TOUCHDOWN, HE LOST DIRECTIONAL CONTROL OF THE AIRCRAFT AND IT SWERVED OFF THE LEFT SIDE OF THE RUNWAY. THE AIRCRAFT'S LEFT MAIN LANDING GEAR COLLAPSED WHEN IT RAN THROUGH SOFT TERRAIN IN A DITCH. THE AIRCRAFT CAME TO A STOP ABOUT 200 FEET FROM THE EDGE OF THE RUNWAY. A POST-ACCIDENT EXAMINATION OF THE AIRCRAFT REVEALED THAT THE CROSS-WIND LANDING GEAR LOCK SYSTEM WAS IMPROPERLY RIGGED. THE LEFT MAIN LANDING GEAR LOCK PIN FAILED TO ENGAGE AND THE LEFT MAIN GEAR WAS FREE TO 'CASTER' DURING TOUCHDOWN AND ON THE LANDING ROLL, WHILE THE RIGHT MAIN GEAR REMAINED LOCKED. THE PILOT HAD RECENTLY PURCHASED THE AIRCRAFT. HE STATED THAT HE SHOULD HAVE PERFORMED A MORE THOROUGH PRE-PURCHASE INSPECTION. HE HAD 175 HOURS TOTAL FLIGHT TIME, WITH 17 HOURS IN THIS MAKE AND MODEL OF AIRCRAFT. HE HAD RECEIVED SPECIFIC INSTRUCTION IN THE AIRCRAFT, BECAUSE OF ITS UNCOMMON DESIGN AND CHARACTERISTICS. ## Aircraft - Registration: [N8750R](https://openairdocs.org/aircraft/N8750R), registered now, S/N 009 (OpenAirDocs) - Reported make and model: HELIO H-391B - Registry model: [Helio H-391B](https://openairdocs.org/model/helio-h-391b) (registry code 4300106) (OpenAirDocs) - Registry engine: [Lycoming GO-435C&D series](https://openairdocs.org/engine/lycoming-go-435c-d-series) (registry code 41521, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 009 - Airframe hours: 2800 - Engines: LYCOMING GO-435-C2B 260 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Gail P. Lown - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 1, 1989, 30 hours before - Departed: DVN, DAVENPORT, IA - Airport: 61D, Otsego-Plainwell Muni, runway 27, 2,650 × 50 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 40; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 175 total, 17 in this make and model, 25 in the last 90 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 20 knots, gusting 35 - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 50 °F, dew point 30 °F - Altimeter: 29.00 inHg - Observed at: AZO, 15 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 19891120046499A](https://openairdocs.org/incident/19891120046499A), Nov 20, 1989: Helio H391B, Plainwell, MI, Substantial damage. Veered off runway on gusty crosswind landing. Left gear collapsed in ditch. Crosswind gear lock rigged improperly. ## Other investigations on N8750R (1) 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. - [NTSB CHI74FEP20](https://openairdocs.org/ntsb/CHI74FEP20), Oct 17, 1973: Helio Acft H-391B (N8750R), Eau Claire, WI, substantial damage 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.