# NTSB SEA93LA173: Piper PA-18-150, N116BH, Sheridan, WY, August 10, 1993 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 10, 1993, 07:15 local (13:15 UTC) - Place: Sheridan, WY - Coordinates: 44.789028, -106.950485 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.7890&lon=-106.9505&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 1, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 41746 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA93LA173 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41746/pdf - Page: https://openairdocs.org/ntsb/SEA93LA173 ## Probable cause THE DUAL STUDENT'S FAILURE TO MAINTAIN DIRECTIONAL CONTROL. A FACTOR CONTRIBUTING TO THE ACCIDENT WAS THE INSTRUCTOR'S DELAYED REMEDIAL ACTION. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - on ground/water, landing - roll - directional control - not maintained, dual student (cause) - remedial action - delayed, pilot in command(cfi) (contributing factor) - On ground/water encounter with terrain/water, landing - roll - ground loop/swerve - inadvertent, pilot in command(cfi) ## Analysis DURING THE LANDING ROLL THE DUAL STUDENT ALLOWED THE AIRCRAFT TO DRIFT RIGHT AND THEN OVER CORRECTED IN AN ATTEMPT TO REGAIN DIRECTIONAL CONTROL. AS THE AIRCRAFT BEGAN TO GROUND LOOP TO THE LEFT, THE INSTRUCTOR PILOT ATTEMPTED TO REGAIN CONTROL BUT WAS UNSUCCESSFUL. THE INSTRUCTOR REPORTED THAT HE WAS SLOW TO TAKE CORRECTIVE ACTION. ## Factual narrative On August 10, 1993, at approximately 0715 hours mountain daylight time (MDT), a conventionally geared Piper PA-18-150, N116BH, registered to and operated by Bighorn Airways, Inc., and being flown by Pamela J. Roberts, a certificated private pilot under the instruction of Forrest L. Asmus, an ATP rated flight instructor, sustained substantial damage during a ground loop during landing rollout on runway 31 at the Sheridan County Airport, Sheridan, Wyoming. Neither pilot was injured. Visual meteorological conditions prevailed and no flight plan had been filed. The instructional flight was to have been operated in accordance with the requirements set forth in 14CFR91 and originated at the Sheridan County Airport at approximately 0645 hours. Instructor Asmus reported that pilot Roberts was executing a (main) wheel landing and that as the aircraft decelerated it began to drift right. As the aircraft approached the right edge of the runway pilot Roberts was reported to overcorrect in an attempt to regain control, and the aircraft began a ground loop to the left. The instructor attempted to regain control with the application of full right brake and rudder. However, the ground looped continued and the right wingtip impacted the pavement. The aircraft was subsequently taxied to the ramp. The instructor reported that he was "too slow to correct for improper student control input." Additionally, he reported that there was no mechanical malfunction with the aircraft during the event. ## Aircraft - Registration: [N116BH](https://openairdocs.org/aircraft/N116BH), registered now, S/N 18-8041, built 1963 (OpenAirDocs) - Reported make and model: PIPER PA-18-150 - Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs) - Registry engine: [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series) (registry code 41505, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: 18-8041 - Airframe hours: 1986 - Engines: LYCOMING O-320-A2B 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Bighorn Airways, Inc. - Registered owner: Bighorn Airways, Inc. - Airworthiness certificate: Standard, Utility; Standard, Normal - Last inspection: Annual, January 15, 1993, 68 hours before - Departed: SHR, WY - Destination: SHR - Airport: SHR, Sheridan County Airport, runway 31, 6,649 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; airline transport, flight instructor; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: rear; flight hours: 12,000 total, 350 in this make and model, 11,700 as pilot in command, 152 in the last 90 days, 56 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 7 knots - Visibility: 50 statute miles - Lowest ceiling: 12,000 ft broken - Temperature: 64 °F, dew point 50 °F - Altimeter: 30.00 inHg - Observed at: SHR ## 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 19930810028429A](https://openairdocs.org/incident/19930810028429A), Aug 10, 1993: Piper PA18150, Sheridan, WY, Substantial damage. Swerved landing over corrected. CFI took over too late to prevent a ground loop. 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.