- Date
- May 17, 2012, 16:02 local (22:02 UTC)
- Place
- Darby, MT
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N471BRotherwick HR Glasair III
- Defining event
- Landing-landing roll: Loss of control on ground
- Weather
- Visual (VMC) · Day
- Status
- Completed · report August 15, 2012
- Report
- Approved by Office Director
- NTSB office
- Western Pacific Region
- Parties
- Federal Aviation Administration
- FAA report
- 20120517008169A
- Case key
- 83676
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
The pilot’s loss of directional control during an emergency landing on a paved highway.
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.
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, about 2 hours into a visual flight rules cross-country flight, he enriched the mixture due to indications of excessive cylinder head and exhaust gas temperatures. This resulted in a higher fuel burn than planned, so he changed the flight’s destination to a closer airport. While en route to his amended destination, he encountered instrument meteorological conditions. A subsequent buildup of ice resulted in a loss of 100 knots of airspeed as the airplane entered a controlled descent. The pilot executed a 180-degree turn and broke out of the clouds over a valley. During the next 50 minutes, he made several attempts to exit the valley; however, mountain peak obscuration and a thunderstorm prevented him from flying out of the valley. Now very close to fuel exhaustion, he elected to land on a two-lane highway. During the landing roll, the airplane veered off the side of the road, impacted a tree, slid backwards through a ditch, and collided with a concrete drainage culvert. The airplane sustained damage to the outboard sections of both wings.
Factual narrative
***This report was modified on August 7, 2012. Please see the dcoket for this accident to view the original report.*** The pilot reported that, about 2 hours into a visual flight rules cross-country flight, he enriched the mixture due to indications of excessive cylinder head and exhaust gas temperatures. This resulted in a higher fuel burn than planned, so he changed the flight’s destination to a closer airport. While en route to his amended destination, he encountered instrument meteorological conditions. A subsequent buildup of ice resulted in a loss of 100 knots of airspeed as the airplane entered a controlled descent. The pilot executed a 180-degree turn and broke out of the clouds over a valley. During the next 50 minutes, he made several attempts to exit the valley; however, mountain peak obscuration and a thunderstorm prevented him from flying out of the valley. Now very close to fuel exhaustion, he elected to land on a two-lane highway. During the landing roll, the airplane veered off the side of the road, impacted a tree, slid backwards through a ditch, and collided with a concrete drainage culvert. The airplane sustained damage to the outboard sections of both wings.
Aircraft
- Registration
- N471B
- Reported as
- Rotherwick HR Glasair III
- Category
- Airplane, amateur-built
- Serial number
- 3380
- Airframe hours
- 150
- Engine
- Lycoming I-540, 540 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Positioning · Part 91
- Operator
- Layne Johnson
- Registered owner
- James M Hammond
- Airworthiness certificate
- Special, Experimental (Special)
- Last inspection
- Condition · August 1, 2011 · 3 hours before
- Departed
- TTD · Troutdale, OR
- Destination
- BIL · Billings, MT
- Flight plan
- VFR
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
- 55
- Injuries
- None
- Certificates
- Commercial, Airline transport
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, With waivers/limitations
- Last flight review
- August 4, 2011
- Seat
- Left
- Flight hours
- 19,896 total · 4 in this make and model
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 230° at 10 knots, gusting 15
- Visibility
- 10 statute miles
- Lowest ceiling
- 8,000 ft broken
- Temperature
- 63 °F, dew point 34 °F
- Altimeter
- 29.79 inHg
- Observed at
- MSO, 60 nm away
Docket · 3
The files NTSB released with the investigation on June 23, 2012, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.1 MB 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.
Other investigations on N471B · 1
Matched to the same aircraft by N-number and date.