# NTSB WPR17LA009: Gray Jim Robert Exec 90, N716JB, Caldwell, ID, October 19, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 19, 2016, 09:10 local (15:10 UTC) - Place: Caldwell, ID - Coordinates: 43.641944, -116.635833 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.6419&lon=-116.6358&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: No injuries - Injuries: 1 uninjured - Status: Completed, report March 5, 2018 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 94240 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR17LA009 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/94240/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=94240 - Page: https://openairdocs.org/ntsb/WPR17LA009 ## Probable cause The pilot's failure to properly tighten the tension bolts during the installation of the alternator belt, which resulted in inadequate voltage to sustain ignition and the subsequent partial loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Ignition system: ignition power supply](https://openairdocs.org/ntsb-findings/01057410): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Gray Jim Robert EXEC, 1 case](https://openairdocs.org/ntsb-findings/01057410/cases.md?model=13017FT), [All aircraft, 13 cases](https://openairdocs.org/ntsb-findings/01057410/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Gray Jim Robert EXEC, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=13017FT), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/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: [Gray Jim Robert EXEC, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=13017FT), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Gray Jim Robert EXEC, 2 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=13017FT), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis Shortly after takeoff for the personal flight, about 15 to 20 ft above ground level, the experimental amateur-built helicopter suddenly yawed right, followed by a partial loss of engine power. The private pilot then performed a partial nose-up, collective-down maneuver, but due to the low altitude and not being able to maintain sufficient rotor rpm, he chose to land in soft dirt off the side of the runway; the helicopter landed hard. The pilot had recently changed the alternator belt. A postaccident examination of the helicopter revealed that, during the maintenance, the pilot failed to properly tighten the tension bolts, which resulted in inadequate voltage to sustain ignition and the subsequent partial loss of engine power. ## Factual narrative On October 19, 2016, about 0910 mountain daylight time, an experimental amateur-built Jim Gray Rotorway Exec 90 helicopter, N716JB, was substantially damaged following a forced landing after experiencing a loss of engine power at the Caldwell Industrial Airport (EUL), Caldwell, Idaho. The private pilot and registered owner of the helicopter was not injured. Visual meteorological conditions prevailed at the time of the accident. The flight was being conducted in accordance with 14 Code of Federal Regulations Part 91, and a flight plan was not filed. The proposed local flight was originating at the time of the accident. In a report submitted to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), the pilot reported that during the takeoff everything seemed normal. He then accelerated and began a slow climb. At between 15 to 20 ft above ground level and about 40 to 45 knots, the helicopter suddenly yawed right, followed by the engine losing power. The pilot stated that being so low he could not perform a normal autorotation. The pilot opined that he did a partial nose-up, collective-down maneuver, but due to the low altitude and not being able to maintain sufficient rotor rpm, he elected to land in the soft dirt off the side of the runway. A hard landing resulted in the helicopter coming to rest on its left side. The helicopter sustained substantial damage to the tail boom and horizontal stabilizer. Subsequent to a postaccident examination of the engine, which was performed by a Federal Aviation Administration aviation safety inspector, the inspector reported to the NTSB IIC that the pilot had recently changed the alternator belt, however, had failed to properly tighten the tension bolts, which resulted in inadequate voltage to sustain ignition, thus precipitating the loss of engine power and hard landing. ## Aircraft - Registration: [N716JB](https://openairdocs.org/aircraft/N716JB), registered now, S/N EXEC-3000 (OpenAirDocs) - Reported make and model: Gray Jim Robert Exec 90 - Registry model: [Gray Jim Robert EXEC](https://openairdocs.org/model/gray-jim-robert-exec) (registry code 13017FT) (OpenAirDocs) - Registry engine: [Rotorway RW-145 series](https://openairdocs.org/engine/rotorway-rw-145-series) (registry code 55005, reciprocating) (OpenAirDocs) - Category: Helicopter, amateur-built - Serial number: Exec-3000 - Year built: 1998 - Airframe hours: 223 - Engines: Rotorway 55005 152 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Continuous airworthiness, February 28, 2016, 223 hours before - Departed: EUL, Caldwell, ID - Destination: EUL, Caldwell, ID - Airport: EUL, Caldwell Industrial, runway 12, 5,500 × 100 ft, asphalt - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 68; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review September 29, 2015; seat: left; restraint: 4-point; flight hours: 577 total, 403 in this make and model, 422 as pilot in command, 50 in the last 90 days, 16 in the last 30 days, 0.2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 40° at 4 knots - Visibility: 8 statute miles - Lowest ceiling: none - Temperature: 37 °F, dew point 36 °F - Altimeter: 30.02 inHg - Observed at: EUL ## 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 20161019021589A](https://openairdocs.org/incident/20161019021589A), Oct 19, 2016: Gray Jim Robert EXEC, Caldwell, ID, Substantial damage. Pilot stated engine failed as helicopter was approx. 20 feet AGL and 50 KIAS. He maneuvered to grass area between the taxiway and runway 12/30 and prepared for… ## Other investigations on N716JB (3) 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 WPR18LA050](https://openairdocs.org/ntsb/WPR18LA050), Dec 17, 2017: Gray Jim Robert Exec (N716JB), Caldwell, ID, substantial damage. Probable cause: Failure of the oil pressure gauge line, which resulted in oil exhaustion and a total loss of engine power. - [NTSB FTW02LA250](https://openairdocs.org/ntsb/FTW02LA250), Sep 5, 2002: Gray Rotorway Exec 90 (N716JB), Las Cruces, NM, substantial damage. Probable cause: The pilot's failure to refuel the helicopter, which resulted in fuel exhaustion. - [NTSB DEN00LA001](https://openairdocs.org/ntsb/DEN00LA001), Oct 1, 1999: Gray Rotorway Exec (N716JB), Gallup, NM, substantial damage. Probable cause: The pilot inadvertently allowing main rotor rpm to decay while avoiding obstacles during an emergency autorotation following a loss of power for reasons undetermined. Factors were houses and… ## Docket (2 files) The files NTSB released with the investigation on December 13, 2017, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=94240. 6.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 4.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40458789&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - FAA Inspector's Report (item 2, .PDF, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40458790&FileExtension=.PDF&FileName=FAA%20Inspector%27s%20Report-Master.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.