# NTSB CEN24LA249: Rotorway 162 F, N426DM, Maybee, MI, July 4, 2024 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: July 4, 2024, 10:43 local (14:43 UTC) - Place: Maybee, MI - Coordinates: 42.0039, -83.5155 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.0039&lon=-83.5155&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 13, 2026 - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA FSDO - NTSB case key (mKey): 194624 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN24LA249 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194624/pdf - Page: https://openairdocs.org/ntsb/CEN24LA249 ## Probable cause A partial loss of engine power for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Unknown/Not determined (probable cause); cases with it: [Naumer Mark 162 F, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=056284W), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Naumer Mark 162 F, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=056284W), [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. - [Landing-flare/touchdown: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Naumer Mark 162 F, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=056284W), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-flare/touchdown: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Naumer Mark 162 F, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=056284W), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Enroute-cruise: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) (defining event); cases with it: [Naumer Mark 162 F, 1 case](https://openairdocs.org/ntsb-events/000/sequence.md?model=056284W), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md) ## Analysis The pilot reported that his preflight inspection of the experimental helicopter revealed no anomalies. About one hour into the flight, the engine and rotor rpm started to drop. When the pilot adjusted the collective and throttle, rotor rpm surged, and engine rpm began to fluctuate. The pilot selected a field and performed a precautionary autorotation. During the touch down, the helicopter’s skids dug into the soft soil and the helicopter spun, which resulted in substantial damage to the main rotor blades, fuselage, and the tail boom. The pilot and the passenger exited the helicopter uninjured. A postaccident examination of the helicopter revealed that fuel remained in the fuel tanks. Examination of the fuel-injected engine did not detect any anomalies that would have precluded normal operation. A roll of blue masking tape was found in the engine cooling shroud, but not in an area that would have interfered with engine operation. Given the lack of anomalies found during the postaccident examination, the reason for the partial loss of engine power could not be determined. ## Factual narrative On July 4, 2024, about 1043 eastern daylight time, an experimental Rotorway 162 F helicopter, N426DM, sustained substantial damage when it was involved in an accident near Maybee, Michigan. The pilot and passenger were not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he conducted a preflight inspection of the helicopter, added fuel, and sumped the fuel tanks. No problems were noted on the preflight. The pilot brought the helicopter into a hover for takeoff, and all the systems checked normal. The pilot took off, climbed the helicopter to about 1,800 ft, and flew locally for about one hour with no problems. Nearing the end of the flight, the pilot noticed that the engine and rotor rpm started to drop. After he adjusted the collective and throttle, the rotor rpm surged, and engine rpm fluctuated. The pilot decided to perform a precautionary autorotation to a field. As the helicopter descended toward the field, the pilot adjusted the cyclic and collective to keep the airspeed at 70 knots, and rotor rpm about 100%. As the helicopter approached the field, the pilot flared the helicopter to arrest the forward momentum. The helicopter contacted the ground with some forward momentum, and the skids dug into soft soil. The tail boom contacted the ground, the helicopter nosed forward, spun about 120°, and came to rest upright, which resulted in substantial damage to the main rotor blades, fuselage, and the tail boom. The pilot and the passenger exited the helicopter uninjured. An examination of the fuel-injected engine was conducted by a certificated mechanic with oversight from the FAA. No anomalies were detected with the engine that would have precluded normal engine operation. Fuel was found in the fuel tanks. A roll of blue masking tape was found in the engine cooling shroud, but not in an area that would result in a loss of engine or rotor rpm. ## Aircraft - Registration: [N426DM](https://openairdocs.org/aircraft/N426DM), registered now, S/N 6355 (OpenAirDocs) - Reported make and model: ROTORWAY 162 F - Registry model: [Naumer Mark 162 F](https://openairdocs.org/model/naumer-mark-162-f) (registry code 056284W) (OpenAirDocs) - Registry engine: [Rotorway RI-162F](https://openairdocs.org/engine/rotorway-ri-162f) (registry code 55007, 4 cycle) (OpenAirDocs) - Category: Helicopter, amateur-built - Serial number: 6355 - Year built: 2010 - Airframe hours: 160 - Engines: Rotorway 162F 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Marchel Christopher M - Airworthiness certificate: Special, Experimental light sport (Special) - Last inspection: Condition, December 4, 2023, 6 hours before - Departed: YIP, Belleville, MI - Airport: YIP, Willow Run - Equipment: ADS-B, Electronic flight bag or handheld device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 51; injuries: none; private; medical: class 3, without waivers/limitations; last flight review June 24, 2023; seat: left; restraint: 4-point; flight hours: 123 total, 29 in this make and model, 64 as pilot in command, 5 in the last 90 days, 1 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 57 °F - Altimeter: 29.95 inHg - Observed at: KTTF, 5 nm away - METAR: KTTF 041435Z AUTO 00000KT 10SM CLR 27/14 A2995 RMK AO2 T02720143 ## 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 20240704010489A](https://openairdocs.org/incident/20240704010489A), Jul 4, 2024: Naumer Mark 162 F, Maybee, MI, Substantial damage. Aircraft departed south of departure airport, with a passenger, destination airport was departure airport. During the flight, the aircraft lost power which… 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.