# NTSB DEN87FA003: Mitsubishi MU-2B-20, N3MU, Denver, CO, October 12, 1986 - Type: NTSB accident investigation - Classification: Accident · No injuries · Field investigation · Final report - Date: October 12, 1986, 10:51 local (16:51 UTC) - Place: Denver, CO - Coordinates: 39.759506, -104.919937 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.7595&lon=-104.9199&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - NTSB case key (mKey): 17075 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN87FA003 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17075/pdf - Page: https://openairdocs.org/ntsb/DEN87FA003 ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, takeoff - initial climb - electrical system,circuit breaker - not engaged (contributing factor) - maintenance - inadequate, company maintenance personnel (contributing factor) - aircraft preflight - inadequate, pilot in command (cause) - lack of familiarity with aircraft, pilot in command (contributing factor) - landing gear - inoperative (contributing factor) - gear retraction - attempted, pilot in command - lack of familiarity with aircraft, copilot/second pilot (contributing factor) - electrical system,circuit breaker - open (cause) - landing gear,gear indicating system - false indication (contributing factor) - Loss of engine power(partial) - nonmechanical, approach - vfr pattern - final approach - precautionary landing - performed, pilot in command - checklist - not followed, pilot in command (cause) - propeller governor control,linkage - incorrect (cause) - maintenance - not corrected, company maintenance personnel (cause) - maintenance,service of aircraft/equipment - inadequate, other maintenance personnel (cause) - Hard landing, landing - flare/touchdown - airspeed(vref) - below, pilot in command (cause) - diverted attention, pilot in command (cause) - stall - inadvertent, pilot in command (cause) ## Analysis ACFT HAD BEEN REPOSSESSED AND WAS BEING FERRIED FROM GRAND JUNCTION, CO, TO CHICAGO, IL, WITH EN ROUTE STOP AT DENVER, CO. AFTER TAKEOFF FROM DENVER, LANDING GEAR WOULD NOT RETRACT. PLT MADE SEVERAL ATTEMPTS WITHOUT SUCCESS. HE ELECTED TO RETURN TO DENVER. PLT SAID THAT ON FINAL APCH THE RIGHT ENG BEGAN SURGING AND THE LEFT ENG WOULD NOT INCREASE PWR. ACFT MADE HARD LANDING ON RWY, BREAKING LEFT WING. INVESTIGATION REVEALED BOTH SPEED LEVERS WOULD NOT FUNCTION BECAUSE ENG PROP GOVERNORS AND UNDERSPEED FUEL GOVERNOR RESET ARMS, SPLINED ONTO UNDERSPEED FUEL GOVERNOR SHAFTS, WERE POSITIONED ON OPPOSITE SIDE OF SPEED LEVER ACTUATING ARMS. LANDING GEAR FUNCTIONED NORMALLY DURING SWING TESTS. IT WAS LATER LEARNED THAT RIGHT MAIN TIRE HAD BLOWN ON TAKEOFF 3 DAYS EARLIER AND REQUIRED REPAIR. MAINTENANCE PERSONNEL OPENED THE LANDING GEAR CIRCUIT BREAKERS TO PRECLUDE INADVERTENT GEAR RETRACTION. PLT SAID HE CHECKED CIRCUIT BREAKERS WHEN GEAR FAILED TO RETRACT. ## Aircraft - Registration: [N3MU](https://openairdocs.org/deregistered/N3MU-1995-01-06), registration cancelled 1995-01-06, S/N 143 (OpenAirDocs) - Reported make and model: MITSUBISHI MU-2B-20 - Registry model: [Mitsubishi MU-2B-20](https://openairdocs.org/model/mitsubishi-mu-2b-20) (registry code 5780407) (OpenAirDocs) - Category: Airplane - Serial number: 143 - Airframe hours: 5780 - Engines: GARRETT TPE331-1-151A 665 horsepower turbo prop - Damage: Substantial damage - Flight: Ferry, Part 91 - Operator: Gene Gartke, doing business as Midway Aircraft Brokers - Registered owner: E. Michael Riebold - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, July 27, 1985, 100 hours before - Destination: MDW, CHICAGO, IL - Flight plan: IFR - Airport: DEN, Stapleton Int'L ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 4,186 total, 38 in this make and model, 4,050 as pilot in command, 25 in the last 90 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 15 statute miles - Lowest ceiling: 25,000 ft overcast - Temperature: 32 °F, dew point 18 °F - Altimeter: 30.00 inHg - Observed at: DEN ## 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 19861012082259A](https://openairdocs.org/incident/19861012082259A), Oct 12, 1986: Mtsbsi MU2B20, Denver, CO, Substantial damage. Wing failed in overload during a hard landing with full tip tanks. Speed lever misrigged. Gear circuit breaker open 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.