# NTSB SEA98LA139: Wsk Pzl Mielec M18B, N4326M, Hingham, MT, July 15, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 14, 1998, 22:10 local (Jul 15, 1998, 04:10 UTC) - Place: Hingham, MT - Coordinates: 48.560867, -110.470252 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=48.5609&lon=-110.4703&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report January 11, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 43229 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA98LA139 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43229/pdf - Page: https://openairdocs.org/ntsb/SEA98LA139 ## Probable cause Restricted aileron travel for undetermined reasons. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, landing - aborted - flt control syst,aileron control - restricted (cause) - reason for occurrence undetermined (cause) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - ground ## Analysis The pilot stated that in his landing attempt, the airplane bounced twice so he decided to go around. He stated that the aircraft then entered an uncommanded right roll, departed the airstrip to the right, and the right wing tip struck the ground. The pilot noted that the left-to-right movement of the control stick was stuck, and that he had applied great pressure on the stick to command a roll to the left. He said the control stick came unstuck and did move to the extreme left, but the aircraft did not respond and continued in its turn or roll to the right. He stated that he pulled the throttle back to idle; the aircraft began to settle to the ground while in this turning motion, went out of control and wrecked. Post-accident examination of the aircraft revealed both aileron bellcranks to be broken where they contacted the upper stops, with the right bellcrank locked in an aileron-up position. However, investigators found no evidence indicating fatigue failure when they inspected the bellcranks. The FAA investigator reported that the airplane had a total airframe time of 103 hours. ## Factual narrative On July 14, 1998, approximately 2210 mountain daylight time, a Polish-manufactured WSK PZL Mielec M18B agricultural aircraft, N4326M, operated by Hutchinson Spraying Service of Hingham, Montana, departed controlled flight and crashed during a landing attempt at the operator's private airstrip approximately 32 miles northwest of Havre, Montana. The airplane was substantially damaged and the airline transport pilot-in-command of the single-seat airplane was not injured. Visual meteorological conditions were reported at Havre at 2156 and no flight plan had been filed for the flight, which was operating under 14 CFR 91 at the time of the accident. The pilot reported to an FAA investigator that he had been spraying late since winds were unfavorable for spraying during the day, and that at the time of the accident, he was landing at his home airstrip after dispensing a load of parathion. He reported that in the landing attempt, he bounced twice and decided to go around. He stated that the aircraft then entered an uncommanded right roll, departed the airstrip to the right, touched its right wing tip to the ground, and crashed. The pilot reported to the FAA investigator that when the uncommanded right roll occurred, the stick was bound to the right. In his written report, the pilot noted that he noticed that the left-to-right movement of the control stick was stuck, and that he had applied great pressure on the stick to command a roll to the left. He said the control stick came unstuck and did move to the left, but the aircraft did not respond to "this extreme left movement of the stick. The aircraft continued in its turn/roll to the right. I pulled the throttle back to idle. The aircraft began to settle to the ground while in this turning motion. The aircraft went out of control and wrecked." The pilot added that "I felt that there was a complete loss of command of aileron or roll of the aircraft.... One thing is for sure. I was flying the airplane and I know how it reacted, and there are, in my opinion, mechanical malfunctions that support my description of how the aircraft flew. It was abnormal." Post-accident examination of the aircraft revealed both aileron bellcranks to be broken where they contacted the upper stops, with the right bellcrank locked in an aileron-up position. However, investigators found no evidence indicating fatigue failure when they inspected the bellcranks. The FAA investigator reported that the airplane had a total airframe time of 103 hours. Astronomical data indicated that at a point 32 nautical miles northwest of the Havre airport, sunset on the evening of the accident was at 2122, with end of evening twilight at 2257. The pilot's airstrip is unlighted. ## Aircraft - Registration: [N4326M](https://openairdocs.org/aircraft/N4326M), registered now, S/N 1Z027-03 (OpenAirDocs) - Reported make and model: Wsk Pzl Mielec M18B - Registry model: [Wsk-Pzl Meilec PZL M18B](https://openairdocs.org/model/wsk-pzl-meilec-pzl-m18b) (registry code 9810125) (OpenAirDocs) - Category: Airplane - Serial number: 12027-03 - Airframe hours: 103 - Engines: WSK PZL KALIS ASZ 62IR-M18 967 horsepower reciprocating - Damage: Substantial damage - Flight: Ferry, Part 91 - Operator: Hutchinson Spraying, Inc. - Registered owner: Mary M. Hutchinson - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, April 6, 1998, 103 hours before - Departed: HINGHAM, MT - Airport: Hutchinson Private, runway 36, 5,280 × 75 ft, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 6,195 total, 102 in this make and model, 5,183 as pilot in command, 100 in the last 90 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Dusk - Wind: 0° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 48 °F - Altimeter: 30.00 inHg - Observed at: HVR ## 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 19980714016649A](https://openairdocs.org/incident/19980714016649A), Jul 14, 1998: Wsk PZLM18B, Hingham, MT, Substantial damage. Landing at base bounced. Began go around. Lost control. Rolled and crashed bell cranks broken. Aileron jammed. (-23) pilot states he bounced twice during a… 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.