Thursday, July 07, 2016

Van's RV-6, N916BN: Accident occurred July 04, 2016 near St. Maries Municipal Airport (S72), Benewah County, Idaho

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

NTSB Identification: WPR16LA135 
14 CFR Part 91: General Aviation
Accident occurred Monday, July 04, 2016 in St. Maries, ID
Probable Cause Approval Date: 10/17/2017
Aircraft: BERT N Norris RV-6, registration: N916BN
Injuries: 2 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The private pilot reported that, on short final to the runway, the engine lost partial power. The pilot then switched fuel tanks, activated the boost pump, and pumped the throttle, but engine power was not restored. The pilot subsequently landed in a field about 300 to 500 ft short of the runway, and the airplane nosed over.  

Postaccident examination of the airplane and engine revealed no mechanical anomalies that would have precluded normal operation. The pilot stated that he believed that the loss of power was due to carburetor ice because he might not have applied carburetor heat during the flight. The weather conditions at the time of the accident were conducive to moderate carburetor icing at cruise power settings and serious carburetor icing at descent power settings. It is likely that the loss of engine power resulted from carburetor icing due to the pilot’s failure to apply carburetor heat.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
A partial loss of engine power due to carburetor icing, which resulted from the pilot’s failure to apply carburetor heat.

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

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Spokane, Washington

Aviation Accident Factual Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms


NTSB Identification: WPR16LA135
14 CFR Part 91: General Aviation
Accident occurred Monday, July 04, 2016 in St. Maries, ID
Aircraft: BERT N Norris RV-6, registration: N916BN
Injuries: 2 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On July 4, 2016, about 0930 Pacific daylight time, a Bert N. Norris RV-6, experimental amateur-built conventional gear airplane, was substantially damaged during a forced landing following a loss of engine power near St. Maries Municipal Airport (S72), St. Maries, Idaho. The airplane was registered to a private individual and operated by the pilot as a 14 Code of Federal Regulations Part 91 personal flight. The private pilot and one passenger were not injured. Visual meteorological conditions (VMC) prevailed and a flight plan was not filed. The flight originated from Homeport Airport (11WA), Cheney, Washington, about 0910.

During a telephone interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on the day following the accident, the pilot stated that while on short final approach to runway 28 at S72, the engine experienced a partial loss of power. He believed the power loss was due to carburetor icing, as he may not have activated the carburetor heat. He then switched fuel tanks, activated the boost pump, pumped the throttle, but was unable to restore power. The pilot reported that he subsequently landed the airplane in a field about 100 yards from the approach end of runway 28. during the landing roll, the airplane nosed over, which resulted in substantial damage to the rudder.

In a written report submitted to the NTSB IIC on July 14, 2016, the pilot reported that as he approached S72 he visually confirmed that the weather was still VMC. He entered the [traffic] pattern for runway 28, began to reduce power on the engine, and while in the turn from base leg to final approach the engine completely quit. The pilot stated that he verified that the carburetor heat and the fuel boost pump were on, after which he changed the fuel selector to the opposite tank. He then looked for a place to land, but most of the fields were filled with hay bales, which prompted him to continue his turn to the airport. The pilot stated that the airplane touched down about 500 ft short of runway 28 and nosed over. The airplane sustained damage to both wings, the rudder and the elevator.

According to a Federal Aviation Administration aviation safety inspector who performed an onsite postaccident examination of the airplane, the inspector reported that he was able to rotate the propeller by hand, that the engine appeared to be in good shape, and the examination revealed no general indication of engine failure that would have been causal to the accident. Additionally, the inspector reported that the pilot relayed to him that carburetor heat might not have been applied during the flight, which may have caused the engine to lose power during the approach to the airport.


According to a carburetor icing probability chart, the reported temperature and dew point at the time of the accident were in a range for moderate carburetor icing at cruise power settings and serious carburetor icing at descent power settings.

NTSB Identification: WPR16LA135
14 CFR Part 91: General Aviation
Accident occurred Monday, July 04, 2016 in St. Maries, ID
Aircraft: BERT N Norris RV-6, registration: N916BN
Injuries: 2 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On July 4, 2016, about 0930 Pacific daylight time, a Bert N. Norris RV-6, experimental amateur-built conventional gear airplane, was substantially damaged during a forced landing following a partial loss of engine power near St. Maries Municipal Airport (S72), St. Maries, Idaho. The private pilot and one passenger were not injured. Visual meteorological conditions prevailed for the flight, which was operated in accordance with 14 Code of Federal Regulations Part 91, and a flight plan was not filed. The flight originated from Homeport Airport (11WA), Cheney, Washington, about 0910.

In a postaccident interview with the National Transportation Safety Board investigator-in-charge, the pilot reported that on short final to runway 28 at an altitude of about 400 feet above ground level, with carburetor heat applied, the engine experienced a partial loss of power. The pilot stated that he switched fuel tanks, activated the boost pump and pumped the throttle, however, he was unable to restore power to the engine. The pilot further stated that knowing he could not make the runway, he elected to make a forced landing in a field off of the approach end of runway 28. During the touchdown/landing roll in high vegetation, the airplane nosed over, which resulted in substantial damage to the rudder. The airplane was recovered to a secure location for further examination.

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