# NTSB FTW98LA309: Overton Mustang M-II, N121GD, Hillsdale, WY, July 11, 1998 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: July 11, 1998, 05:15 local (11:15 UTC) - Place: Hillsdale, WY - Coordinates: 41.210277, -104.479293 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.2103&lon=-104.4793&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report February 15, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 43164 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW98LA309 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43164/pdf - Page: https://openairdocs.org/ntsb/FTW98LA309 ## Probable cause The pilot's inadequate visual lookout and his failure to maintain adequate clearance from obstacles. Factors were an intentional low altitude flight maneuver, wires, and low light conditions. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, maneuvering - low altitude flight/maneuver - intentional, pilot in command (contributing factor) - visual lookout - inadequate, pilot in command (cause) - clearance - not maintained, pilot in command (cause) - object - wire,static (contributing factor) - light condition - dawn (contributing factor) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - roadway/highway - object - bridge/overpass ## Analysis The pilot said he heard a 'slight hesitation or miss' in the engine and increased power slightly. The engine gauges registered normal and the engine seemed to 'smooth out.' He sighted a road below and descended to assess its suitability for a possible forced landing in case the engine lost power. He felt the airplane strike something and shudder, then heard a loud rumbling noise. The airplane struck wires that crossed the road, impacted the roadway, then collided with a bridge. ## Factual narrative On July 11, 1998, approximately 0515 mountain daylight time, N121GD, an Overton Mustang M-II, was destroyed when it collided with wires and impacted terrain near Hillsdale, Wyoming. The private pilot, the sole occupant aboard, was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under Title 14 CFR Part 91. The flight originated at Erie, Colorado, approximately 0440. In a telephone interview from his hospital bed, the pilot said the engine began to "miss" and "run rough." He sighted a road below and descended to assess its suitability for an emergency landing. The airplane struck wires that crossed the road, impacted the roadway, then collided with a bridge. In his accident report, the pilot said the flight was to be a local personal flight "with no particular destination in mind." He heard a "slight hesitation or miss" in the engine and increased power slightly. The engine gauges registered normal and the engine seemed to "smooth out." He descended to survey a road "as a possible landing spot in case of an engine failure." He felt the airplane strike something and shudder, then heard a loud rumbling noise. The airplane then struck the ground. ## Aircraft - Registration: [N121GD](https://openairdocs.org/deregistered/N121GD-2003-03-13), registration cancelled 2003-03-13, S/N M-II-1217, built 1994 (OpenAirDocs) - Reported make and model: OVERTON MUSTANG M-II (MUSTANG M-) - Registry model: [Overton Gaylon D OVERTON MUSTANG M-II](https://openairdocs.org/model/overton-gaylon-d-overton-mustang-m-ii) (registry code 1690472) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: MII-1217 - Airframe hours: 250 - Engines: Lycoming O-320-E2D 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Gaylon D. Overton - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, September 1, 1997, 30 hours before - Departed: 48V, ERIE, CO ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 475 total, 250 in this make and model, 450 as pilot in command, 15 in the last 90 days, 6 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Dawn - Wind: 220° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 57 °F, dew point 54 °F - Altimeter: 30.00 inHg - Observed at: CYS ## 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 19980711025059A](https://openairdocs.org/incident/19980711025059A), Jul 11, 1998: Amtr MUSTANG2, Hillsdale, WY, Substantial damage. Engine missing. Elected land on highway. Struck wires surveying area. Wires hidden by early dawn. No landing light. (.4) the pilot said he heard a `slight… 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.