# NTSB WPR18LA098: Raytheon A36, N207PC, Enumclaw, WA, March 4, 2018 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: March 4, 2018, 15:58 local (23:58 UTC) - Place: Enumclaw, WA - Coordinates: 47.202499, -121.994163 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.2025&lon=-121.9942&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Continental Motors, Textron Aviation, Federal Aviation Administration, Hartzell Engine Technologies - NTSB case key (mKey): 96818 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR18LA098 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/96818/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=96818 - Page: https://openairdocs.org/ntsb/WPR18LA098 ## Probable cause A total loss of engine power due to oil starvation as a result of a loose oil line B-nut. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Raytheon A36, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=7150001), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Fluids: oil](https://openairdocs.org/ntsb-findings/01071020): Aircraft › Fluids/misc hardware · Fluid level (probable cause); cases with it: [Raytheon A36, 3 cases](https://openairdocs.org/ntsb-findings/01071020/cases.md?model=7150001), [All aircraft, 174 cases](https://openairdocs.org/ntsb-findings/01071020/cases.md) - [Misc hardware: fasteners](https://openairdocs.org/ntsb-findings/01071430): Aircraft › Fluids/misc hardware · Not serviced/maintained (probable cause); cases with it: [Raytheon A36, 1 case](https://openairdocs.org/ntsb-findings/01071430/cases.md?model=7150001), [All aircraft, 58 cases](https://openairdocs.org/ntsb-findings/01071430/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Raytheon A36, 9 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7150001), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Raytheon A36, 9 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7150001), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-flare/touchdown: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Raytheon A36, 17 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7150001), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot was at cruise altitude en route on a cross-country flight from Arizona to Washington when he noted that the engine oil pressure indicated zero and the manifold pressure was near zero. He then heard “…a loud bang, as though the engine had thrown a rod.” The cabin filled with smoke and oil covered the windscreen, and the pilot conducted a forced landing into a stand of trees, during which the airplane sustained substantial damage. Examination of the airframe revealed no anomalies that would have precluded normal operation. An examination of the engine revealed three holes in the crankcase, each consistent with an internal engine failure. All six cylinders remained attached to their respective cylinder bays; there was no indication of impact damage. The Nos. 2, 4 and 5 connecting rods had separated from the crankshaft. All rod bearings displayed lubrication distress consistent with oil starvation. The oil line B-nut attached to the turbocharger scavenge check valve was loose. Based on the available information, it is likely that the loose oil line B-nut resulted in a gradual loss of oil during the long cross-country flight, which subsequently resulted in the separation of the connecting rods due to oil starvation and a total loss of engine power. ## Factual narrative A review of maintenance records revealed that the engine was disassembled, repaired, and all cylinders overhauled in 2011 due to low compression on the #4 and the #6 cylinders, "bad exhaust valves on each," and a "bad lifter" and camshaft lobe on #4 exhaust. On November 25, 2011, the engine was converted from normally aspirated to turbo-normalized in accordance with supplemental type certificates SA5223NM and SE5222NM. The most recent annual inspection was completed on October 17, 2017 at a Hobbs time of 1,009.2 hours. The most recent engine maintenance was performed on January 9, 2018, at a Hobbs time of 1,041.2 hours, during which the No. 2 cylinder was removed and replaced. On March 4, 2018, about 1558 Pacific standard time, a Raytheon Aircraft Company A36 airplane, N207PC, was substantially damaged when it was involved in an accident near Enumclaw, Washington. The private pilot was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he was en route on a 975-nautical mile nm cross-country flight when he chose to file an instrument flight rules flight plan due to weather ahead on his route. Shortly after being cleared to descend from 16,000 ft to 11,000 ft mean sea level, the pilot noted zero engine oil pressure and near-zero manifold pressure indications and immediately declared an emergency with air traffic control. The pilot stated that, about this time, he heard “…a loud bang, as though the engine had thrown a rod,” the cabin filled with smoke, and oil covered the windscreen. The pilot stated that, “…the engine continued to break apart, emitting loud noises, as if more rods or cylinders were breaking.” The pilot reported that as he descended over the Cascade mountain range, the area was mostly enveloped in instrument meteorological conditions, although he did have visual contact with the ground through small openings in the clouds. The controller provided vectors to nearby airports but realizing that the airplane was not within glide distance, the pilot chose to make a controlled landing into trees. As the airplane impacted the trees, the tail section and the left wing separated, and the airplane came to rest in a thick grove of trees. All major components of the airplane were accounted for at the accident site and the wreckage was recovered for further examination. During the initial examination of the engine, three holes were noted in the crankcase. The Nos. 2 and 4 connecting rods were separated from the crankshaft and the turbocharger housing and impeller were impact damaged; the impeller was free to rotate by hand. The oil scavenge pump line B-nut connection was loose. Due to the extensive damage, the engine was subsequently shipped to the manufacturer for a detailed examination and disassembly. The largest hole was toward the rear of the crankcase and spanned both crankcase halves. One hole was located in the right crankcase half near the No. 3cylinder, and the third hole was located in the left crankcase half near the No. 4 cylinder. All six cylinders remained attached to their respective cylinder bays, with no indication of impact damage. All four main bearings remained within the bearing supports, and there were no signs of bearing shift. The bearings displayed smearing and damage consistent with lubrication distress. The crankshaft remained intact and there were no signs of impact damage signatures. The main bearing journals displayed normal operating signatures. The Nos. 1 and 6 connecting rod journals displayed normal operating signatures. The Nos. 2, 3, 4, and 5 connecting rod journals displayed thermal damage signatures consistent with lack of lubrication; the Nos. 4 and 5 connecting rod journals displayed mechanical damage. The No. 4 connecting rod oil galley was blocked with redeposited metal. The rest of the oil galleys were clear of blockages. The crankshaft gear remained intact and was undamaged. Further examination revealed that all valves and guides remained intact and were undamaged. All valve heads displayed normal operating and combustion signatures. There were no anomalies noted with the valves. All rocker arms remained intact and undamaged and displayed normal operating signatures. The Nos. 1, 2, 5 & 6 pistons remained attached to their respective connecting rods and displayed a significant amount of mechanical damage to the rear of each piston. The piston faces displayed normal operating and combustion signatures. The rear piston ring for each displayed mechanical damage and was broken; the rest of the piston rings remained within their grooves and were undamaged. Piston No. 3 remained attached to its connecting rod and displayed scoring along the piston skirt. The piston face displayed normal operating and combustion signatures. The piston rings remained within their grooves and displayed normal operating signatures. Piston No. 4 remained attached to its connecting rod and displayed a significant amount of mechanical damage to the rear of the piston. The piston face displayed semicircular indentations consistent with valve strikes; there were no signs of detonation or preignition. The rear piston ring displayed mechanical damage and was broken; the rest of the piston rings remained within their grooves and were undamaged. There were no anomalies noted with the piston. The Nos. 2, 4, and 5 connecting rods released from their journals. The connecting rods displayed varying amounts of thermal damage consistent with lubrication distress. The camshaft displayed significant mechanical damage and was broken into two pieces at the No. 3 camshaft journal; the forward portion of the camshaft displayed bending and impact marks and the damage corresponded with the same area as the released No. 5 connecting rod. The lifters remained installed and displayed varying amounts of mechanical damage. All accessory gears remained installed in their installation points and displayednormal operating and lubrication signatures. Examination of the turbocharger revealed no evidence of preaccident mechanical anomalies. Data from the airplane's onboard engine monitor revealed that, about 10 minutes before the end of the accident flight, exhaust gas temperature (EGT) and cylinder head temperature (CHT) values for cylinders Nos. 1, 2, and 4 begin to diverge. EGT and CHT values for cylinder No. 1 continued to diverge until stabilizing before the end of the recording. For additional information, refer to the NTSB Vehicle Recorder Division Engine Data Monitor (EDM) Specialist’s Factual Report, which is appended to the docket for this accident. ## Aircraft - Registration: [N207PC](https://openairdocs.org/deregistered/N207PC-2019-11-21), registration cancelled 2019-11-21, S/N E-3503 (OpenAirDocs) - Reported make and model: RAYTHEON AIRCRAFT COMPANY A36 - Registry model: [Raytheon A36](https://openairdocs.org/model/raytheon-a36) (registry code 7150001) (OpenAirDocs) - Category: Airplane - Serial number: E-3503 - Year built: 2003 - Airframe hours: 1069.1 - Engines: Continental IO-550B39 300 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 17, 2017, 28 hours before - Departed: NYL, Yuma, AZ - Destination: PAE, Everett, WA - Flight plan: IFR - Equipment: Auto-pilot, Data recorder, Electronic flight bag or handheld device, Electronic primary flight display, Handheld GPS, Onboard weather, Stall warning system, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: serious; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; seat: left; flight hours: 930 total, 200 in this make and model, 820 as pilot in command, 30 in the last 90 days, 12 in the last 30 days, 10 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 160° at 6 knots - Visibility: 5 statute miles - Lowest ceiling: 800 ft overcast - Temperature: 43 °F, dew point 37 °F - Altimeter: 30.21 inHg - Turbulence: Light - Observed at: SEA, 25 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 20180304001419A](https://openairdocs.org/incident/20180304001419A), Mar 4, 2018: Raytheon Aircraft Company A36, Enumclaw, WA, Destroyed. Acft departed yuma, AZ (nyz) for paine field, everett, WA (pae). Report from ATC sea center: acft declares an emergency with smoke and loss of power. ATC… ## Docket (10 files) The files NTSB released with the investigation on March 10, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=96818. 21.1 MB in all. - Engine data monitor - specialist's factual report (item 1, PDF, 5 pages, 803 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12032109&FileExtension=pdf&FileName=Engine%20Data%20Monitor%20-%20Specialist%27s%20Factual%20Report-Rel.pdf - Engine data monitor - specialist's factual report - attachment 1 (item 2, CSV, 308 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7981224&FileExtension=csv&FileName=Attachment%201%20to%20Engine%20Data%20Monitor%20-%20Specialist%27s%20Factual%20Report-Rel.csv - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 3, PDF, 11 pages, 3.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11882165&FileExtension=pdf&FileName=Pilot%20accident%20report%20form_Redacted-Rel.pdf - Accident site maps (item 4, PDF, 2 pages, 2.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11872879&FileExtension=pdf&FileName=Accident%20site%20maps-Rel.pdf - Continental motors engine examination report (item 5, PDF, 40 pages, 6.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11873247&FileExtension=pdf&FileName=Continental%20Motors%20engine%20examination%20report_Redacted-Rel.pdf - Textron technical report (item 6, PDF, 7 pages, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11881472&FileExtension=pdf&FileName=Textron%20Technical%20report_Redacted-Rel.pdf - Maintenance records (item 7, PDF, 5 pages, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11881977&FileExtension=pdf&FileName=Engine%20log%20book%20entries%20-%20excerpts%20from%20maintenance%20records_Redacted-Rel.pdf - Evidence control forms (item 8, PDF, 4 pages, 3.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11882175&FileExtension=pdf&FileName=Evidence%20Control%20forms_Redacted-Rel.pdf - Statement of party representatives to NTSB investigation (item 9, PDF, 3 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11873532&FileExtension=pdf&FileName=NTSB%20party%20forms_redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 10, PDF, 1 page, 689 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11873051&FileExtension=pdf&FileName=NTSB%20Release%20of%20Wreckage%20form_redacted-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.