WPR19LA132

NTSB accident investigation · Otterback Lightning · Woodland, WA · May 1, 2019

Accident · No injuriesClass 3 · LimitedFinal report
Date
May 1, 2019, 10:30 local (17:30 UTC)
Place
Woodland, WA
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N106ALOtterback Lightning
Defining event
Landing: Loss of engine power (total)
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Western Pacific Region
Parties
Federal Aviation Administration
FAA report
20190501003749A
Case key
99365

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

A complete loss of engine power due to carburetor icing.

Findings · 2

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Temp/humidity/pressure: conducive to carburetor icingEnvironmental issues › Conditions/weather/phenomena · Effect on operationOtterback Nicholas L LIGHTNING: 1 caseAll aircraft: 435 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

The pilot reported that after an uneventful flight in an experimental airplane he set up for landing. At about 1,200 feet he reduced the throttle to idle, turned on the carburetor heat, and entered the traffic pattern. After turning final, when the pilot began to reach for the throttle, the propeller stopped spinning. The engine had lost complete power, with no engine roughness or abnormal noises. Since the airplane was about 50 ft above the ground, the pilot continued to land onto the runway. The airplane bounced and when it touched back down, the airplane departed the left side of the runway. The pilot redirected the airplane back toward the runway surface, but the nose gear collapsed on the rough grass. The nearest weather reporting station indicated temperature 13°C, dewpoint 4°C. Review of the Carburetor Icing Probability Chart revealed that, given the temperature and dewpoint, the conditions were on the line between serious icing at glide power and serious icing at cruise power. During a telephone conversation the pilot reported that the carburetor heat system takes hot air from near the muffler to keep the carburetor from icing up. It is likely that the carburetor accumulated ice while in cruise flight and the carburetor heat, when applied when the pilot reduced the throttle to idle, was not sufficient to remove the carburetor ice which resulted in a loss of engine power.

Factual narrative

On May 1, 2019, about 1030 Pacific daylight time, an experimental, amateur-built Lightning airplane, N106AL, was substantially damaged when it was involved in an accident at the Woodland State Airport (W27), Woodland, Washington. The pilot and passenger were not injured. The airplane was operated under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. The pilot reported that after an uneventful flight he entered the traffic pattern at about 1,200 ft above ground level (agl), reduced power to idle and turned on the carburetor heat. After turning to final approach, the engine lost complete power, with no engine roughness or abnormal noises. Since the airplane was about 50 ft above the ground, the pilot continued to land onto the runway. The airplane bounced and when it touched back down, the airplane departed the left side of the runway. The pilot redirected the airplane back toward the runway surface, but the nose gear collapsed on the rough grass substantially damaging the lower fuselage and engine mounts. The airplane is equipped with an experimental Jabiru 3300 engine. During a telephone conversation the pilot reported that the carburetor heat system takes hot air from near the muffler to keep the carburetor from icing. However, when the airplane is at idle for an extended period, the engine and exhaust cool, and the air being supplied to the carburetor is not as hot, making the carburetor susceptible to carburetor ice, particularly in severe icing conditions. The 0953 automated weather observation at the Scappoose Industrial Airpark (SBP), Scappoose, Oregon, located about 9 miles southwest of the accident site, included calm wind, visibility 10 statute miles, clear skies, temperature 13°C, dewpoint 4°C, and an altimeter setting of 30.11 inches of mercury. Review of the Carburetor Icing Probability Chart in the Federal Aviation Administration Special Airworthiness Information Bulletin for Carburetor Ice Prevention revealed that, given temperature and dewpoint, the conditions were on the line between serious carburetor icing at glide power and serious carburetor icing at cruise power.

Aircraft

Registration
N106AL
Reported as
Otterback Lightning
Category
Airplane, amateur-built
Serial number
111
Built
2011
Airframe hours
458
Engine
Jabiru 3300, 120 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Condition · November 12, 2018
Departed
S50 · Auburn, WA
Destination
W27 · Woodland, WA
Airport
W27 · Woodland State Airport, runway 32, 1,953 × 25 ft, asphalt
Equipment
Unknown

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
62
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, With waivers/limitations
Last flight review
September 28, 2017
Seat
Left
Restraint
3-point
Flight hours
830 total · 79 in this make and model

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
10 statute miles
Lowest ceiling
None
Temperature
55 °F, dew point 39 °F
Altimeter
30.11 inHg
Observed at
SPB, 9 nm away

Docket · 3

The files NTSB released with the investigation on April 20, 2022, on NTSB’s docket system: statements, records, photos and specialists’ reports. 545 KB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.