# NTSB WPR24LA009: Stephen D Phillabaum Helicycle, N519SP, Deer Park, WA, October 1, 2023 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: October 1, 2023, 13:20 local (20:20 UTC) - Place: Deer Park, WA - Coordinates: 47.894536, -117.4398 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.8945&lon=-117.4398&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Fuel starvation](https://openairdocs.org/ntsb-events/191) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report September 30, 2025 - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 193215 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR24LA009 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193215/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193215 - Page: https://openairdocs.org/ntsb/WPR24LA009 ## Probable cause A loss of engine power due to fuel starvation resulting from contamination of the fuel system during low-level flight. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Power plant](https://openairdocs.org/ntsb-findings/01057100): Aircraft › Aircraft power plant · Unknown/Not determined (probable cause); cases with it: [Stephen D Phillabaum HELICYCLE, 1 case](https://openairdocs.org/ntsb-findings/01057100/cases.md?model=05635VH), [All aircraft, 198 cases](https://openairdocs.org/ntsb-findings/01057100/cases.md) - [Fluids](https://openairdocs.org/ntsb-findings/01071000): Aircraft › Fluids/misc hardware · Related operating info (probable cause); cases with it: [Stephen D Phillabaum HELICYCLE, 1 case](https://openairdocs.org/ntsb-findings/01071000/cases.md?model=05635VH), [All aircraft, 11 cases](https://openairdocs.org/ntsb-findings/01071000/cases.md) - [Fuel system: fuel storage](https://openairdocs.org/ntsb-findings/01022810): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Stephen D Phillabaum HELICYCLE, 1 case](https://openairdocs.org/ntsb-findings/01022810/cases.md?model=05635VH), [All aircraft, 60 cases](https://openairdocs.org/ntsb-findings/01022810/cases.md) - [Fuel system: fuel distribution](https://openairdocs.org/ntsb-findings/01022820): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Stephen D Phillabaum HELICYCLE, 1 case](https://openairdocs.org/ntsb-findings/01022820/cases.md?model=05635VH), [All aircraft, 141 cases](https://openairdocs.org/ntsb-findings/01022820/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Fuel starvation](https://openairdocs.org/ntsb-events/191) (defining event); cases with it: [Stephen D Phillabaum HELICYCLE, 1 case](https://openairdocs.org/ntsb-events/191/sequence.md?model=05635VH), [All aircraft, 733 cases](https://openairdocs.org/ntsb-events/191/sequence.md) ## Analysis The pilot reported that he had not flown the experimental amateur-built helicopter for 3 months, so he performed several practice liftoffs to a hover and landings. He then departed and flew a modified airport traffic pattern with the intent of terminating the approach to a hover. During the circling approach, about 50 ft above ground level (agl), he added power to increase the helicopter’s altitude and airspeed, but the engine lost total power. The pilot attempted to arrest the descent, but the helicopter landed hard, which resulted in substantial damage to the tailrotor driveshaft and tailrotor gearbox. Postaccident examination of the airframe fuel system revealed that the main fuel tank contained excess hardened sealant pieces found at the base of the tank, near the fuel pickup points that fed into the left and right fuel tanks. The size and shape of the excess sealant was too large to flow through the fuel lines and may have precipitated a fuel starvation event. Foreign object debris in the form of dirt-like particulates were observed from the cross-feed outflow fuel fitting to the fuel filter input. The left and right fuel tanks, fuel filter, and fuel collator all contained foreign object debris in the form of dirt-like particulates. Given the extraordinary quantity of foreign object debris in the airframe’s fuel system, foreign object debris accumulation, specifically at the fuel fitting entry points, likely resulted in fuel starvation and a loss of engine power during the pilot’s increased collective application and corresponding increased power demand. The source of the foreign object debris was undetermined. ## Factual narrative On October 1, 2023, about 1320 Pacific daylight time, an experimental amateur-built Helicycle, N519SP, was substantially damaged when it was involved in an accident near Dear Park, Washington. The pilot was seriously injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he had not flown helicopter in over 3 months, and he performed several practice liftoffs to a hover and landings before departing to the northeast to fly a modified airport traffic pattern. He continued his left turn to the west with the intent of terminating the approach to a hover. The pilot reported that during the left turn and about 50 ft agl he “added power to increase airspeed and altitude” when the engine lost power. He lowered the collective, rolled out of the turn and attempted to arrest the descent, but the helicopter landed hard, resulting in substantial damage to the tailrotor driveshaft and tailrotor gearbox. NTSB investigators did not travel to the accident site. Postaccident examination of the helicopter’s fuel system, showed that the experimental amateur-built helicopter was equipped with three polypropylene fuel tanks. The main fuel tank was fabricated with a vent and two fuel lines at the base of the tank; one fuel line at the left base fed into a fuel tank on the left side of the helicopter, and one fuel line on the right base of the tank fed into a fuel tank on the right side of the helicopter. The left and right side fuel tanks were equipped with fuel quantity indicators, and a cross-feed fitting that fed into the fuel filter. The anodized aluminum fuel filter was intact, disassembled, and revealed an observable quantity of foreign particulates inside the body of the filter, as well as the inflow orifice. The left and right fuel tanks contained dirt-like debris, which was also found in the cross-feed outflow fuel fitting to the fuel filter input. The main fuel tank revealed hardened pieces of sealant affixed to arbitrary locations at the base of the tank. The pieces of sealant were too large to flow through the fuel lines into the subsequent left and right fuel tanks. The gascolator, filter screen, O-rings, and rubber seal were intact. However, an observable quantity of dirt-like debris was trapped inside the gascolator and staining was observed inside the fuel bowl. The fuel control assembly was affixed to the fuel pump, securely mated to the accessory case, and appeared unremarkable. ## Aircraft - Registration: [N519SP](https://openairdocs.org/aircraft/N519SP), registered now, S/N 5-19, built 2018 (OpenAirDocs) - Reported make and model: STEPHEN D PHILLABAUM HELICYCLE - Registry model: [Stephen D Phillabaum HELICYCLE](https://openairdocs.org/model/stephen-d-phillabaum-helicycle) (registry code 05635VH) (OpenAirDocs) - Registry engine: [Solar T62T-32](https://openairdocs.org/engine/solar-t62t-32) (registry code 58102, turbo-shaft) (OpenAirDocs) - Category: Helicopter, amateur-built - Serial number: 5-19 - Year built: 2018 - Airframe hours: 44 - Engines: Solar T62T-32A 150 horsepower turbo shaft - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, September 1, 2023, 0 hours before - Departed: WT21, Deer Park, ID - Destination: Same as departure - Airport: WT21, Radial Flyer, runway 4, 2,200 × 60 ft, grass/turf - Equipment: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 75; injuries: serious; commercial, flight instructor, private; airplane ratings: single-engine sea, single-engine land; instrument ratings: airplane; medical: basicmed, with waivers/limitations; last flight review June 16, 2022; seat: single; restraint: 5-point; flight hours: 3,500 total, 44 in this make and model, 0 in the last 90 days, 0 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 40° at 9 knots, gusting 17 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 63 °F, dew point 39 °F - Altimeter: 30.01 inHg - Observed at: KDEW, 5 nm away - METAR: METAR KDEW 011953Z AUTO 04009G17KT 10SM CLR 17/04 A3001 RMK AO2 SLP163 T01720039 $= ## 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 20231001018049A](https://openairdocs.org/incident/20231001018049A), Oct 1, 2023: Stephen D Phillabaum HELICYCLE, Deer Park, WA, Substantial damage. The pilot stated that he had not flown his helicopter in a while and decided he would hover around to practice takeoffs and landings. Pilot said he was… ## Docket (4 files) The files NTSB released with the investigation on September 30, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193215. 3.0 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17958446&FileExtension=pdf&FileName=6120_1_Redacted-Rel.pdf - Memorandum for record - FAA inspector (item 2, PDF, 1 page, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16587496&FileExtension=pdf&FileName=Memorandum%20for%20Record%20of%20Examination-Rel.pdf - Memorandum for record -ammons (item 3, PDF, 2 pages, 73 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18985748&FileExtension=pdf&FileName=Memorandum%20for%20Record%20-%20Ammons-Rel.pdf - Photographs (item 4, PDF, 3 pages, 840 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16587280&FileExtension=pdf&FileName=Photographs-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.