Sunday, March 22, 2020

Fuel Related: Belite Pipper, N3748; accident occurred May 23, 2018 at Lake Hood Seaplane Base (PLHD), Anchorage, Alaska

Engine valves

Cylinder valve 

Engine Piston

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity: 

Federal Aviation Administration / Flight Standards District Office; Anchorage, Alaska

Aviation Accident Factual Report - National Transportation Safety Board:

Investigation Docket - National Transportation Safety Board:

Location: Anchorage, AK
Accident Number: ANC18LA038
Date & Time: 05/23/2018, 1630 AKD
Registration: N3748
Aircraft Damage: Substantial
Defining Event: Fuel related
Injuries:1 Minor 
Flight Conducted Under: Part 91: General Aviation - Personal 

On May 23, 2018, about 1630 Alaska daylight time, a Belite Pipper, experimental amateur built airplane, N3748, sustained substantial damage during a forced landing, following a total loss of engine power at Lake Hood Seaplane Base (PLHD), Anchorage, Alaska. The airplane was registered to a private individual and operated by the pilot as a 14 Code of Federal Regulations (CFR) Part 91 visual flight rules flight when the accident occurred. The private pilot sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight departed PLHD for a local flight in the airport traffic pattern.

According to the pilot, the accident flight was the first flight since maintenance was performed on the airplane's fuel system. The pilot stated that he departed Runway 32 and entered a right downwind to remain in the traffic pattern. While on final approach to Runway 32, he elected to execute a go-around. After advancing the throttle, when about 150 ft above ground level (AGL), all engine power was lost. He said the engine quit like there was no fuel. He did not see or hear anything that would be consistent with a mechanical failure.

During the forced landing, the pilot attempted to land back on the runway, but touched down between the runway end lights, bounced, and became airborne again. With no remaining runway surface available, the airplane descended into a fence and came to rest inverted in marshy terrain about 375 ft from the departure end of Runway 32. The airplane sustained substantial damage to the fuselage and both wings.

A post-accident examination of the Rotax 912 UL2 engine was performed by the NTSB investigator-in-charge along with another NTSB investigator. After removing the rocker box covers, all rocker arms exhibited discoloration consistent with high heat exposure. When the number 4 cylinder was removed, the valve was discovered fractured and a witness mark was present consistent with piston contact.

The engine had been altered from its original state by the addition of an Edge Performance Big Bore Kit. The kit, considered a high displacement cylinder/piston kit, was to increase performance and horsepower of the engine. As a result of the modification, the fuel requirements increased over that of a stock 912 UL2 engine. As installed, the kit replaced the crankshaft, camshaft, engine gaskets, cylinders and pistons. The fuel supply system remained the same and no modifications were made to the carburetors.

The pilot stated in a phone conversation that he had been discussing with the kit manufacturer a problem with fuel flow to the engine, which is why he was performing maintenance on it the day before and day of the accident. He said he had replaced all fuel lines and fittings with larger fuel lines but made no changes to the carburetors. During subsequent ground tests, fuel flow at the carburetors was measured between 1.8 – 2.0 psi.

Prior to the above-mentioned maintenance, after allowing the engine to warm up, when he would apply full power, the engine would quit and the carburetor bowls would be empty. The pilot stated that since the engine continued to run after changing the fuel lines, the "ground tests seemed good with the exception of the fuel pump pressure." 

Pilot Information

Certificate: Private
Age: 59, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present:No 
Instructor Rating(s):None 
Toxicology Performed: No
Medical Certification: BasicMed None
Last FAA Medical Exam: 04/03/2018
Occupational Pilot:No 
Last Flight Review or Equivalent: 03/26/2017
Flight Time:   2076 hours (Total, all aircraft), 222 hours (Total, this make and model), 2007 hours (Pilot In Command, all aircraft), 66 hours (Last 90 days, all aircraft), 46 hours (Last 30 days, all aircraft) 

Aircraft and Owner/Operator Information

Aircraft Make: JAMES WIEBE
Registration: N3748
Aircraft Category: Airplane
Year of Manufacture: 2017
Amateur Built:Yes 
Airworthiness Certificate: Experimental
Serial Number: 001
Landing Gear Type: Tailwheel
Seats: 2
Date/Type of Last Inspection: 04/27/2018, Condition
Certified Max Gross Wt.: 1232 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 156 Hours as of last inspection
Engine Manufacturer: Rotax
ELT: C126 installed, not activated
Engine Model/Series:912UL2 
Registered Owner:On file 
Rated Power:122 hp 
Operator:On file 
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: PALH, 90 ft msl
Distance from Accident Site: 1 Nautical Miles
Observation Time: 2353 UTC
Direction from Accident Site: 172°
Lowest Cloud Condition: Clear
Visibility:  10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 18 knots / 26 knots
Turbulence Type Forecast/Actual: / None
Wind Direction: 180°
Turbulence Severity Forecast/Actual: / N/A
Altimeter Setting: 29.76 inches Hg
Temperature/Dew Point: 12°C / 2°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Anchorage, AK (LHD)
Type of Flight Plan Filed: None
Destination: Anchorage, AK (LHD)
Type of Clearance: None
Departure Time:  AKD
Type of Airspace: Class D

Airport Information

Airport: LAKE HOOD (LHD)
Runway Surface Type: Dirt
Airport Elevation: 79 ft
Runway Surface Condition: Holes; Rough; Standing Water; Soft; Vegetation; Wet
Runway Used: 32
IFR Approach: None
Runway Length/Width: 2200 ft / 75 ft
VFR Approach/Landing: Forced Landing; Go Around; Traffic Pattern 

Wreckage and Impact Information

Crew Injuries: 1 Minor
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 Minor
Latitude, Longitude: 61.190278, -149.969444


  1. Hot rod upgrade to the Rotax made every flight a test flight. Fortunate that the power loss was somewhere that allowed landing and survival.

  2. It is certainly not the first modified Rotax to have trouble. How would you expect you could increase the power by 25 hp (approximately) and make no change to the carburetors. Just stupidity.

    1. And the kit developer/supplier should have included fuel system assessment in the install instructions. It is either no change required or "requires fuel upgrade kit p/n xxx-yy".

      For automotive carbs, tuning by size change of numbered jets made that a simple job, but of course you can pull off to the side of the road if your mods fail in a non-flight application.