# NTSB CEN18LA280: Best Off Skyranger, N4329R, Houghton Lake, MI, July 8, 2018 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: July 8, 2018, 06:43 local (10:43 UTC) - Place: Houghton Lake, MI - Coordinates: 44.32611, -84.78833 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.3261&lon=-84.7883&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Federal Aviation Administration, Grand Rapids FSDO - SAIBs cited in the narratives: [SAIB CE-09-35](https://openairdocs.org/saib/CE-09-35) (OpenAirDocs) - NTSB case key (mKey): 97817 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN18LA280 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/97817/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=97817 - Page: https://openairdocs.org/ntsb/CEN18LA280 ## Probable cause A partial loss of engine power during takeoff for undetermined reasons. ## 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: [Mcintire John P SKYRANGER, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=05901O8), [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. - [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Mcintire John P SKYRANGER, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=05901O8), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Mcintire John P SKYRANGER, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=05901O8), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Mcintire John P SKYRANGER, 1 case](https://openairdocs.org/ntsb-events/092/sequence.md?model=05901O8), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The pilot was conducting a local private flight when the airplane had a sudden loss of engine power shortly after takeoff. The pilot reported that after an uneventful takeoff, as the airplane climbed through 150 ft above ground level, the engine speed rapidly decreased from 6,200 rpm to 4,700 rpm. Despite the pilot's corrective actions, the engine continued to operate at a decreased power setting and the airplane was unable to maintain altitude. The pilot reported that there were trees ahead of the airplane's flight path, so he turned into the wind and maneuvered to land on a nearby golf course fairway. The pilot stated that the airplane had insufficient altitude and airspeed to flare normally, which resulted in a hard landing and substantial damage to both wings and the empennage. The pilot reported that he did not observe any anomalies during his preflight inspection or his before-takeoff engine runup, and that the fuel tank contained about 12 gallons of automotive fuel. A postaccident engine examination did not reveal any evidence of mechanical malfunctions or failures that would have precluded normal operation during the flight. Although the atmospheric conditions were conducive for the formation of carburetor icing, the airplane's engine was equipped with carburetors with a variable-venturi design that are generally not prone to carburetor icing. Therefore, the reason for the partial loss of engine power could not be determined with the available evidence. ## Factual narrative On July 8, 2018, about 0643 eastern daylight time, a Best Off Skyranger experimental light-sport airplane, N4329R, was substantially damaged when it was involved in an accident at Houghton Lake State Airport (5Y2), Houghton Lake, Michigan. The pilot sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, he did not observe any anomalies with the airplane or its engine during the preflight inspection or the before-takeoff engine run-up. The fuel tank contained about 12 gallons of automotive fuel before the flight. The pilot reported that the takeoff roll, rotation, and initial climb from runway 16 were uneventful; however, as the airplane climbed through 150 ft above ground level, the engine speed rapidly decreased from 6,200 rpm to 4,700 rpm. He verified that the throttle was full forward, the ignition switch was selected to both, the fuel valve was open, and that available fuel was in the tank. The pilot also turned on the electric fuel pump. Despite the pilot's corrective actions, the engine continued to operate at a decreased power setting, and the airplane was unable to maintain altitude. The pilot reported that there were trees ahead of the airplane's flightpath, so he made a turn into the wind and maneuvered to land on a nearby golf course fairway. The pilot stated that the airplane had insufficient altitude and airspeed to flare normally, which resulted in a hard landing on the fairway. A postaccident wreckage examination was completed by a Federal Aviation Administration (FAA) airworthiness inspector. The FAA inspector reported that both wings and the empennage sustained substantial damage during the forced landing. The Rotax 582 engine did not exhibit any crankcase or cylinder fractures, and there were no oil/fluid leaks observed on the exterior engine components. The firewall-mounted oil reservoir contained ample engine oil. The three-blade propeller remained attached to the engine and exhibited blade damage consistent with rotation at impact. Two spark plugs, one from each cylinder, were removed and exhibited normal wear signatures. The remaining two spark plugs were damaged during the accident and were not removed. Both carburetors had separated from their respective induction tubes during impact; however, both carburetor throttle arms remained attached to the control cable that was continuous to the cockpit throttle. A partial disassembly of both carburetors revealed ample automotive fuel in their respective bowls. No contamination was observed in the carburetor bowls or the fuel screens. The FAA inspector rotated the propeller by hand and confirmed mechanical continuity of the internal drivetrain components of the engine. The dual electronic ignition system appeared undamaged and was not tested. The postaccident examination did not reveal any evidence of a mechanical malfunction that would have precluded normal engine operation during theflight. According to a carburetor icing probability chart contained in FAA Special Airworthiness Information Bulletin CE-09-35, entitled "Carburetor Icing Prevention", the recorded temperature and dew point were in the range of susceptibility for the formation of carburetor icing. The bulletin notes that if ice forms in the carburetor of a fixed-pitch propeller aircraft, the restriction to the induction airflow will result in roughness in engine operation and a drop in engine speed. The airplane was not equipped with a carburetor heat system; however, the engine was equipped two variable-venturi sliding carburetors (e.g. sliding carburetors) that are generally not prone to carburetor icing, according to Aircraft Powerplants, Fifth Edition by Bent/McKinley. ## Aircraft - Registration: [N4329R](https://openairdocs.org/aircraft/N4329R), registered now, S/N 481, built 2002 (OpenAirDocs) - Reported make and model: Best Off SKYRANGER (No Series) - Registry model: [Mcintire John P SKYRANGER](https://openairdocs.org/model/mcintire-john-p-skyranger) (registry code 05901O8) (OpenAirDocs) - Registry engine: [Rotax 582SER](https://openairdocs.org/engine/rotax-582ser) (registry code 55556, 2 cycle) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 481 - Year built: 2002 - Airframe hours: 292.7 - Engines: Rotax 582 65 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental light sport (Special) - Last inspection: Condition, April 7, 2018, 8.4 hours before - Airport: 5Y2, Houghton Lake State, runway 16, 2,750 × 104 ft, grass/turf - Equipment: Electronic flight bag or handheld device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; injuries: serious; sport pilot; airplane ratings: single-engine land; medical: sport pilot; last flight review February 5, 2018; seat: left; restraint: 4-point; flight hours: 45.3 total, 7 in this make and model, 12 as pilot in command, 7 in the last 90 days, 7 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 63 °F, dew point 50 °F - Altimeter: 30.32 inHg - Observed at: HTL, 6 nm away ## 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 20180708015879A](https://openairdocs.org/incident/20180708015879A), Jul 8, 2018: Mcintire John P SKYRANGER, Houghton Lake, MI, Substantial damage. On July 08, 2018 at 0643 eastern daylight time, an experimental Mcintire sky ranger aircraft N4329R, registered to and operated by a sport pilot, received… ## Docket (7 files) The files NTSB released with the investigation on March 31, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=97817. 1.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 808 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11722013&FileExtension=pdf&FileName=01-%20Pilot%20Report_Redacted-Rel.pdf - Memorandum of conversation (pilot) (item 2, PDF, 1 page, 71 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11722697&FileExtension=pdf&FileName=02%20-%20Memorandum%20of%20Conversation%20(Pilot)-Rel.pdf - Memorandum of conversation (FAA inspector) (item 3, PDF, 1 page, 71 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11722619&FileExtension=pdf&FileName=03%20-%20Memorandum%20of%20Conversation%20(FAA%20Inspector)-Rel.pdf - Weather (item 4, PDF, 1 page, 100 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11722637&FileExtension=pdf&FileName=04%20-%20Weather-Rel.pdf - SAIB CE-09-35 carb icing prevention (item 5, PDF, 3 pages, 106 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11723103&FileExtension=pdf&FileName=05%20-%20SAIB%20CE-09-35%20Carb%20Icing%20Prevention_Redacted-Rel.pdf - Carburetor icing article (item 6, PDF, 2 pages, 460 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11723133&FileExtension=pdf&FileName=06%20-%20Carburetor%20Icing%20Article_Redacted-Rel.pdf - Photo (item 7, PDF, 1 page, 1 photo, 230 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11722538&FileExtension=pdf&FileName=05%20-%20Photo-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.