# NTSB WPR18LA050: Gray Jim Robert Exec, N716JB, Caldwell, ID, December 17, 2017 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 17, 2017, 13:00 local (20:00 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: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-hover: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 5, 2019 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 96490 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR18LA050 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/96490/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=96490 - Page: https://openairdocs.org/ntsb/WPR18LA050 ## Probable cause Failure of the oil pressure gauge line, which resulted in oil exhaustion and a total loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Eng oil sys (airframe furnish): engine oil indicating system](https://openairdocs.org/ntsb-findings/01057930): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Gray Jim Robert EXEC, 1 case](https://openairdocs.org/ntsb-findings/01057930/cases.md?model=13017FT), [All aircraft, 3 cases](https://openairdocs.org/ntsb-findings/01057930/cases.md) - [Fluids: oil](https://openairdocs.org/ntsb-findings/01071020): Aircraft › Fluids/misc hardware · Fluid level (probable cause); cases with it: [Gray Jim Robert EXEC, 1 case](https://openairdocs.org/ntsb-findings/01071020/cases.md?model=13017FT), [All aircraft, 174 cases](https://openairdocs.org/ntsb-findings/01071020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-hover: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Gray Jim Robert EXEC, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=13017FT), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Maneuvering-hover: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Gray Jim Robert EXEC, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=13017FT), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Gray Jim Robert EXEC, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=13017FT), [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: [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 The private pilot was performing hover-taxi maneuvers in the experimental amateur-built helicopter when the engine lost all power, which resulted in a forced landing in a field during which the airplane landed hard. Postaccident examination revealed that the engine had seized due to oil exhaustion after the oil pressure gauge line had failed, causing most of the engine oil to be expelled overboard with an insufficient quantity of oil in the sump for engine operation. The pilot, who was also the helicopter builder, had installed the oil pressure gauge line, which was made of automotive-grade nylon tubing, about 1 year before the accident. Because the helicopter had an experimental airworthiness certificate and was considered to be an amateur-built aircraft, the pilot could use non-aviation grade components. The pilot discarded the oil line before it could be examined, so its failure mode could not be determined. ## Factual narrative On December 17, 2017, about 1300 mountain standard time, an experimental amateur-built Rotorway Exec-90 series helicopter, N716JB, landed hard following a loss of engine power at Caldwell Industrial Airport, Caldwell, Idaho. The private pilot/builder was not injured, and the helicopter sustained substantial damage to the lower fuselage structure. The helicopter was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The local flight departed Caldwell about 1230. The pilot stated that he planned to perform a series of hover-taxi and air-taxi maneuvers on taxiway A as practice, after a two-week period of bad weather. After taxiing around the airport for about 30 minutes, he heard an unusual sound and the engine began to lose power. He was initiating a turn at the time, and as the helicopter descended to 10 ft, the engine lost all power. He performed a forced landing, and the helicopter landed hard. Examination of the helicopter revealed that oil was leaking from below the engine compartment, and a trail of oil was present on the ground in the areas that the helicopter had been taxing. Following the accident, the pilot recovered the helicopter to his hangar and removed the body panels around the engine. He stated that the sump contained about 2 quarts of oil (capacity 5 quarts), and the engine appeared to have seized. An inspector from the Federal Aviation Administration (FAA) performed an external inspection and found that all the visible major oil lines were intact and tight at their fittings, and there did not appear to be any catastrophic breaches or damage to the engine crankcase. A few months after the accident the pilot began to disassemble the helicopter for repair, and discovered that the oil pressure gauge line, which was attached to the oil filter housing by a brass compression fitting, had failed and separated from the fitting. He stated that the line was made of nylon tubing, which he purchased from a local automobile parts store. He had installed the tubing about one year before the accident, after the original kit-supplied plastic line had degraded and was leaking oil into the cabin. The pilot discarded the oil line before it could be examined by the FAA or NTSB. According to FAA Advisory Circular AC 20-27G, Certification and Operation of Amateur-Built Aircraft, "Amateur builders are free to develop their own designs or build from existing designs. We do not approve these designs and it would be impractical to develop design standards for the wide variety of design configurations, created by designers, kit manufacturers, and amateur builders." Photo 1 – Helicopter at Accident Site Photo 2 – Oil on Ramp Previous Accidents The pilot was involved in three previous accidents in the accident helicopter, all involving a loss of power: On October 19, 2016, the helicopter lost powerduring the initial takeoff climb (accident number: WPR17LA009). The NTSB determined the probable cause to be, "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." On September 5, 2002, the helicopter lost power shortly after takeoff (accident number: FTW02LA250). The NTSB determined the probable cause to be, "The pilot's failure to refuel the helicopter, which resulted in fuel exhaustion." On October 1, 1999, the helicopter lost power while in the traffic pattern (accident number: DEN00LA001). The NTSB determined the probable cause to be, "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 powerlines." ## 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: 317 - Engines: Rotorway RW-152 152 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, August 5, 2017, 21 hours before - Departed: EUL, Caldwell, ID - Destination: EUL, Caldwell, ID - Airport: EUL, Caldwell Industrial - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 70; injuries: none; private; airplane ratings: single-engine land; instrument ratings: helicopter, airplane; medical: class 3, with waivers/limitations; last flight review October 19, 2017; seat: left; restraint: 4-point; flight hours: 691 total, 317 in this make and model, 33.4 in the last 90 days, 11.1 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 90° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: 6,000 ft overcast - Temperature: 36 °F, dew point 23 °F - Altimeter: 30.28 inHg - Observed at: KEUL ## 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 20171217023219A](https://openairdocs.org/incident/20171217023219A), Dec 17, 2017: Gray Jim Robert EXEC, Caldwell, ID, Substantial damage. While performing what the pilot called "taxi way pattern work" (flying 40' AGL above the airport taxiways @ 10-20 KTS) the engine made a unusual noise. The… ## 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 WPR17LA009](https://openairdocs.org/ntsb/WPR17LA009), Oct 19, 2016: Gray Jim Robert Exec 90 (N716JB), Caldwell, ID, substantial damage. 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… - [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 October 22, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=96490. 1.3 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40467604&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Pilot Interview Summary (item 2, .PDF, 106 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40467605&FileExtension=.PDF&FileName=Pilot%20Interview%20Summary-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.