# NTSB WPR21LA086: Hughes 269C, N7480F, Spanish Fork, UT, January 13, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: January 13, 2021, 13:50 local (20:50 UTC) - Place: Spanish Fork, UT - Coordinates: 40.130849, -111.6879 - Nearby events: https://openairdocs.org/map.md?lat=40.1308&lon=-111.6879&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Nose over/nose down](https://openairdocs.org/ntsb-events/096) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Schweizer Aircraft, Lycoming Engines - NTSB case key (mKey): 102524 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA086 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102524/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102524 - Page: https://openairdocs.org/ntsb/WPR21LA086 ## Probable cause The loss of engine power during a practice autorotation for an undetermined reason. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Hughes 269C, 2 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=4470504), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Autorotation: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Hughes 269C, 3 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=4470504), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490); cases with it: [Hughes 269C, 1 case](https://openairdocs.org/ntsb-events/490/sequence.md?model=4470504), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) - [Landing: Nose over/nose down](https://openairdocs.org/ntsb-events/096) (defining event); cases with it: [Hughes 269C, 1 case](https://openairdocs.org/ntsb-events/096/sequence.md?model=4470504), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The pilot receiving instruction was preparing for his upcoming checkride for a rotorcraft certificate. About 50 minutes into the flight, the flight instructor announced a simulated engine failure, and the pilot receiving instruction reduced throttle, lowered collective, and entered an autorotation. When the helicopter approached 500 ft above ground level (agl) and the instructor advised the pilot to recover, they realized that the engine had stopped producing power. The instructor took control of the helicopter about 200 ft agl and started to flare about 30 ft agl. He raised collective to cushion the landing, but the helicopter still had forward airspeed when it touched down on the soft ground, which resulted in a noseover. Postaccident examination of the helicopter did not reveal any preimpact mechanical anomalies with the airframe or the engine. An engine run showed that with the throttle at the idle detent, the engine cut out intermittently, and the engine idle speed was about 500 rpm lower than the minimum idle speed given in the Pilot’s Operating Manual (POH) for the helicopter. However, the engine power could be advanced from idle to higher speeds, and the engine never lost power as occurred during the accident flight. The flight instructor reported that the pilot receiving instruction would rapidly reduce throttle for practice autorotations, and the POH warned against rapid throttle reduction as it could result in a sudden stoppage of the engine; however, given that the pilot receiving instruction had been following this practice throughout the flight and during previous flights without issue, it is unlikely his rapid throttle reduction led to the loss of power. The investigation was unable to determine the reason for the loss of engine power. The pilot receiving instruction had started his recovery from about 500 ft agl, which required the instructor to re-establish the autorotation following the loss of power. Although the instructor was successful in re-establishing autorotation, he was unable to fully arrest the helicopter’s forward motion before touchdown. ## Factual narrative On January 13, 2020, about 1350 mountain standard time, a Hughes 269C helicopter, N7480F, was substantially damaged when it was involved in an accident near Spanish Fork, Utah. The instructor and the pilot receiving instruction were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The pilot receiving instruction stated that he was preparing for his rotorcraft certificate and was practicing for his upcoming checkride when the accident occurred. According to the flight instructor, they performed an uneventful preflight inspection and started the helicopter. The pilot receiving instruction reported that during the engine run-up, which was performed at 2,500 rpm, he reduced engine power to idle and observed normal rotor and engine rpm separation. The instructor stated that after departure, they entered the airport traffic pattern and performed several landings and three autorotative maneuvers. They subsequently departed the airport traffic pattern and flew to a nearby practice area west of the airport. After performing two recoveries from settling with power, they elected to return to the airport. During cruise flight at 6,500 ft mean sea level, about 1,500 ft above ground level (agl), the instructor announced a simulated engine failure, and the pilot receiving instruction decreased power to idle and lowered collective to enter an autorotation. As the helicopter descended to 500 ft agl, the instructor advised the pilot receiving instruction to recover; however, they realized that the engine had stopped producing power. According to the pilot receiving instruction, the instructor took control of the helicopter about 200 ft agl during an estimated 1,600 ft per minute rate of descent. The instructor stated that he started a flare as the helicopter passed below 30 ft agl to reduce airspeed and rate of descent. The instructor then raised the collective to cushion their landing and further reduce the rate of descent. The helicopter had about 7 mph of forward movement as it contacted the soft ground. The helicopter nosed over, and the main rotor blades contacted the tailboom, which separated from the helicopter. The front right skid tube broke, and the helicopter rolled onto its right side before it came to rest. The checklist that was found on board the helicopter contained a section titled “ENGINE WARMUP AND GROUND CHECK” that included a condensed procedure from the Pilot’s Operating Handbook (POH). The section began with “set engine to 2500 rpm” and continued with several steps including a control check before ending with the following steps: Raise collective (14” [manifold pressure] MP at 2500 rpm). Perform magneto check, (maximum drop in 5 sec). Stabilize engine at 2500 rpm. Position collective full down. Close throttle, observe engine and rotor needles separation. Stabilize engine at 2500 rpm. Boost pump “ON”. The onboard checklist also included a section titled “ENGINE COOLING ANDSHUTDOWN PROCEDURE” that was condensed from the POH. Following steps for an engine cooldown, the section continued with the following steps: Set engine at 1400 rpm. Set clutch control switch to “RELEASE”. Wait for rotor rpm to drop below 100 rpm. Radios “OFF”. Mixture IDLE CUT OFF”. The section ended with several more steps for turning switches off and closing the fuel valve. The helicopter POH stated that a check of idle speed was required at the end of the last flight of each day before engine shut down. The purpose of the check was to determine whether the engine idle speeds were within required limits. This was accomplished with two individual checks; tThe first check (throttle into full override) should produce an idle speed of no less than 1400 rpm; and the second (throttle at normal idle stop) should produce an idle speed no greater than 1600 rpm. The procedure stated that the pilot should notify maintenance personnel if the idle speeds were not within required limits. The POH section that discussed the procedure for a practice autorotation included the following warning: To reduce the chance of engine stoppage when initiating practice autorotations or simulated forced landing training the throttle shall not be abruptly retarded to the idle position. The pilot receiving instruction, who was a co-owner of the helicopter, stated that he performed an engine check before each flight by running the engine up to 1,800 rpm and observing the gauges, oil pressure, and fuel pressure. After performing a magneto check, he would then reduce throttle and observe the rotor and engine rpm split. He stated that he would never reduce throttle below 1,200 rpm even during simulated engine failures. According to the pilot receiving instruction, he did not rapidly reduce throttle during any of the practice autorotations. The instructor stated that the pilot receiving instruction typically reduced power within 1 second during simulated engine failures. The pilot receiving instruction stated that he was not familiar with the POH procedure for a check of engine idle speed at the end of the last flight of the day. The flight instructor reported that they followed the shutdown procedure from the onboard checklist after each flight. During postaccident examination, continuity was confirmed from the anti-torque pedals to the tail rotor through the bellcrank and push-pull tube. Cyclic control continuity was confirmed from the cockpit to the swashplate. The throttle control was moved through its full range from idle to full, and the throttle cable linkage to the carburetor moved accordingly. The mixture control was manipulated from full lean to rich with no discrepancies. Manipulation of the engine drive pulleys turned the main rotor and the tail rotor drive shaft. The drive belts were cut so that the engine could be run without movement of the main and tail rotor drives. A postaccident engine run showed that the engine idled at 500 to 750 rpm at which setting it wouldrun rough and cut out periodically. According to the POH, the engine should idle between 1,200 and 1,600 rpm. A magneto check at 1,800 rpm showed a drop of about 300 rpm when the ignition was switched to the left and right magnetos individually. The engine ran smoothly when engine power was increased to 2,500 rpm. ## Aircraft - Registration: [N7480F](https://openairdocs.org/deregistered/N7480F-2023-01-14), registration cancelled 2023-01-14, S/N 170570, built 1977 (OpenAirDocs) - Reported make and model: HUGHES 269C - Registry model: [Hughes 269C](https://openairdocs.org/model/hughes-269c) (registry code 4470504) (OpenAirDocs) - Registry engine: [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series) (registry code 41524, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 170570 - Year built: 1977 - Airframe hours: 4961.5 - Engines: LYCOMING HIO-360-DIA 190 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Trike Industries LLC - Registered owner: Trike Industries LLC - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, December 18, 2020, 15 hours before - Departed: SPK, Spanish Fork, UT - Airport: SPK, Spanish Fork Muni/Woodhouse Fld - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 38; injuries: none; commercial, flight instructor; instrument ratings: helicopter; medical: class 1, without waivers/limitations; last flight review March 11, 2020; seat: right; restraint: 4-point; flight hours: 3,649 total, 404 in this make and model, 3,571 as pilot in command, 21 in the last 90 days, 10 in the last 30 days - Pilot; age 55; injuries: none; private; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review November 19, 2020; seat: left; restraint: 4-point; flight hours: 1,973 total, 68.6 in this make and model, 1,889 as pilot in command, 70 in the last 90 days, 23 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 5 knots - Visibility: 10 statute miles - Temperature: 39 °F, dew point 21 °F - Altimeter: 30.28 inHg - Observed at: KPVU, 6 nm away - METAR: KPVU 132056Z 30005KT 10SM BKN085 04/M06 A3028 RMK AO2 SLP270 T00391061 58020 ## Other investigations on N7480F (2) 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 ATL96LA063](https://openairdocs.org/ntsb/ATL96LA063), Mar 10, 1996: Hughes 269C (N7480F), Gulf Shores, AL, substantial damage. Probable cause: The failure of both pilots to maintain an adequate visual lookout. A factor was the lack of position reports via radio by the pilot of the helicopter. - [NTSB MKC80DCD30](https://openairdocs.org/ntsb/MKC80DCD30), Aug 14, 1980: Hughes 269C (N7480F), Ellsworth, IA, substantial damage ## Docket (11 files) The files NTSB released with the investigation on July 28, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102524. 25.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 4.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13266714&FileExtension=pdf&FileName=NTSB%20Helicopter%20Damage%20Report%20Hughes%20300C_Redacted-Rel.pdf - Record of conversations (item 2, PDF, 3 pages, 131 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13275701&FileExtension=pdf&FileName=record%20of%20conversations-Rel.pdf - Electronic mail correspondence with pilot receiving instruction (item 3, PDF, 3 pages, 74 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13275469&FileExtension=pdf&FileName=email%20correspondence%20pilot%20receiving%20instruction_Redacted-Rel.pdf - Checklist from accident helicopter (item 4, PDF, 2 pages, 11.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13275834&FileExtension=pdf&FileName=Checkllist-Rel.pdf - Powerplant limitations and hv curve (item 5, PDF, 4 pages, 800 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13275627&FileExtension=pdf&FileName=excerpt%20from%20POH-Rel.pdf - Practice autorotation procedures from pilot's operating handbook (item 6, PDF, 1 page, 122 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13275711&FileExtension=pdf&FileName=Manual%20warning%20about%20throttle%20operation-Rel.pdf - Section 4-15 from pilot's operating handbook (item 7, PDF, 3 pages, 285 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13275035&FileExtension=pdf&FileName=Flight%20manual%20section%204-15-Rel.pdf - NTSB helicopter examination report (item 8, PDF, 8 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14193528&FileExtension=pdf&FileName=WPR21LA086,%20Summary%20of%20Airplane%20Exam-Rel.pdf - Statement of party representatives to NTSB investigation (item 9, PDF, 2 pages, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13274501&FileExtension=pdf&FileName=Party%20agreements_Redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 10, PDF, 1 page, 84 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13275025&FileExtension=pdf&FileName=release%20of%20wreckage_Redacted-Rel.pdf - Accident photographs (item 11, PDF, 3 pages, 4.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13282865&FileExtension=pdf&FileName=Accident%20Photographs-Rel.pdf 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.