Sunday, September 10, 2017

Cessna 172 Skyhawk, N5703A: Accident occurred September 10, 2017 at Cavanaugh Bay Airport (66S), Coolin, Bonner County, Idaho

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

Aviation Accident Factual Report - National Transportation Safety Board:

NTSB Identification: GAA17CA526
14 CFR Part 91: General Aviation
Accident occurred Sunday, September 10, 2017 in Coolin, ID
Aircraft: CESSNA 172, registration: N5703A
Injuries: 1 Serious, 3 Uninjured.

NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.

The pilot reported that he completed a normal landing to the south at a grass airstrip, near a lake and surrounded by 75 ft. tall pine trees. He added that he and his passengers ate lunch at the airstrip, and during that time, he noticed "mostly calm" wind with an "occasional gust from the south." The pilot further reported that, due to the runway gradient, he decided to takeoff downhill to the north, as the windsock was indicating a calm wind.

During the soft field takeoff, he reported that the take-off roll was normal, but about 100 ft. above ground he noticed that the "climb had slowed" and the "airspeed was dropping." The pilot lowered the nose, the airplane "descended quickly," and touched down on the runway with about 30 ft. remaining. Subsequently, the airplane overran the runway, crossed a road, and impacted a dumpster and trees.

The fuselage and both wings sustained substantial damage. 

The pilot reported that the airplane was 25 lbs. under maximum gross weight. 

The pilot did not report that there were any preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

An automated weather observation station (AWOS), about the time of the accident, 13 nautical miles from the accident site, reported wind from 240° at 6 knots. A review of four, hourly AWOSs, south and east of the accident site, around the time of the accident, recorded wind variable from the southwest to westerly direction, at 5 to 10 knots, gusting 15 to 18 knots. The pilot reported that the takeoff was on runway 33. The calculated density altitude was 3,700 ft. According to the Federal Aviation Administration density altitude Koch Chart, the airplane would have likely experienced a 32% decrease to the normal climb rate, and a 50% increase to the normal takeoff distance. 

The Federal Aviation Administration's Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25B, contains a section titled "Effect of Obstructions on Wind" which stated in part:

"Another atmospheric hazard exists that can create problems for pilots. Obstructions on the ground affect the flow of wind and can be an unseen danger. Ground topography and large buildings can break up the flow of the wind and create wind gusts that change rapidly in direction and speed. These obstructions range from man-made structures, like hangars, to large natural obstructions, such as mountains, bluffs, or canyons. It is especially important to be vigilant when flying in or out of airports that have large buildings or natural obstructions located near the runway.

The intensity of the turbulence associated with ground obstructions depends on the size of the obstacle and the primary velocity of the wind. This can affect the takeoff and landing performance of any aircraft and can present a very serious hazard."

COOLIN, Idaho - A Cessna 172 with four people onboard crashed while taking off from the Cavanaugh Bay Airport around 2:45 p.m. on Sunday near the south banks of Priest Lake.

The Spokane pilot and his three passengers walked away from the crash with minor injuries.

The pilot told KXLY he encountered windshear (a phenomenon that can affect a plane's airspeed) during takeoff. He declined to provide any further comments.

Witnesses described seeing a plane struggling to takeoff. At one point, the plane pitched 90 degrees, struck its wing on the pavement and slid across Cavanaugh Bay road on its nose. The Cessna came to a stop feet away from a propane tank and several buildings. 

"The fact that they walked out of there alive was amazing," said Gena Costa, who was bartending in a restaurant nextdoor to the crash site. Employees and customers rushed to help those inside. Costa said one man had a cut on his head.

"I'm so happy that they are alive," said Costa. "To see the actual collision and crash in front of your eyes, it's just crazy. How did they live?"

Story and video ➤

COOLIN, Idaho -  Firefighters are investigating after a small plane crashed near Priest Lake in Coolin, Idaho, Sunday afternoon.

Coolin Fire Chief Peggy Smith reports four people were in the plane when it crashed trying to take off from a grass air strip at Cavanaugh Bay. Smith says there were minor injuries as a result of the crash, but no one was taken to the hospital. 

The plane landed nose down up against a fence.

The cause of the crash is still under investigation Sunday.

Original article can be found here ➤

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