# NTSB WPR12CA213: Rotherwick HR Glasair III, N471B, Darby, MT, May 17, 2012 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: May 17, 2012, 16:02 local (22:02 UTC) - Place: Darby, MT - Coordinates: 45.988334, -114.167221 - Nearby events: https://openairdocs.org/map.md?lat=45.9883&lon=-114.1672&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 15, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 83676 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR12CA213 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/83676/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=83676 - Page: https://openairdocs.org/ntsb/WPR12CA213 ## Probable cause The pilot’s loss of directional control during an emergency landing on a paved highway. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Rotherwick HR GLASAIR III, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=056291J), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Rotherwick HR GLASAIR III, 2 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=056291J), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: VFR encounter with IMC](https://openairdocs.org/ntsb-events/401); cases with it: [Rotherwick HR GLASAIR III, 1 case](https://openairdocs.org/ntsb-events/401/sequence.md?model=056291J), [All aircraft, 392 cases](https://openairdocs.org/ntsb-events/401/sequence.md) - [Maneuvering: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Rotherwick HR GLASAIR III, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=056291J), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Rotherwick HR GLASAIR III, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=056291J), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Rotherwick HR GLASAIR III, 2 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=056291J), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Rotherwick HR GLASAIR III, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=056291J), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## 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](https://openairdocs.org/deregistered/N471B-2018-01-04), registration cancelled 2018-01-04, S/N 3380 (OpenAirDocs) - Reported make and model: Rotherwick HR Glasair III - Registry model: [Rotherwick HR GLASAIR III](https://openairdocs.org/model/rotherwick-hr-glasair-iii) (registry code 056291J) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 3380 - Airframe hours: 150 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; injuries: none; 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 ## 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 20120517008169A](https://openairdocs.org/incident/20120517008169A), May 17, 2012: Rotherwick Hr GLASAIR III, Darby, MT, Substantial damage. Pilot states the weather was changing rapidly, attempted to divert to kbzn but unable, turned to divert to 6S5 (hamilton, MT) but valley was blocked by a… ## Other investigations on N471B (1) 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. - [NTSB WPR11CA022](https://openairdocs.org/ntsb/WPR11CA022), Oct 21, 2010: Rotherwick Glasair III (N471B), Colville, WA, substantial damage. Probable cause: The pilot's misjudged approach and failure to attain the proper touchdown point, which resulted in a runway overrun. ## Docket (3 files) The files NTSB released with the investigation on June 23, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=83676. 3.1 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 644 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370486&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Weather Data (item 2, .PDF, 2.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370487&FileExtension=.PDF&FileName=Weather%20Data-Master.PDF - August 2012 Revisions to Factual Report (item 3, .PDF, 56 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40375068&FileExtension=.PDF&FileName=August%202012%20Revisions%20to%20Factual%20Report-Master.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.