Tuesday, August 27, 2019

Cessna P206 Super Skylane, N131DV: Accident occurred July 14, 2019 at Sulphur Creek Ranch Airport (ID74), Cascade, Valley County, Idaho

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

Additional Participating Entities:
Federal Aviation Administration / Flight Standards District Office; Boise, Idaho
Continental Motors; Mobile, Alabama

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

https://registry.faa.gov/N131DV

Location: Cascade, ID
Accident Number: WPR19LA190
Date & Time: 07/14/2019, 0630 MDT
Registration: N131DV
Aircraft: Cessna P206
Injuries: 3 None
Flight Conducted Under: Part 91: General Aviation - Personal 

On July 14, 2019 about 0630 mountain daylight time, a Cessna P206, N131DV, collided with willow brush shortly after departing from Sulphur Creek Ranch Airport, Cascade, Idaho. The pilot, the brother-in-law of the registered owner, was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The commercial pilot and two passengers were not injured; the airplane sustained substantial damage to the wing. The personal cross-country flight was originating from Sulphur Creek Ranch with a planned destination of Driggs-Reed Memorial Airport, Driggs, Idaho. Visual meteorological conditions prevailed and no flight plan had been filed.

The pilot's family owned the remote ranch, which was only accessible by hike or flying to the private-use landing strip near the property. On the afternoon prior to the accident, the pilot's brother-in-law passed away from a heart attack while hiking with his wife near the ranch. The purpose of the accident flight was for the pilot to transport his sister and grandson in his brother-in-law's airplane back to their home in Wyoming. The pilot stated that he had intended to first land in Driggs to obtain more fuel before continuing to Gillette, Wyoming.

The pilot stated that after a normal preflight and engine run-up, he taxied for a departure to the east (totaling a 7-8 minute engine operating time). After the airplane departed and reached about 75 feet above ground level (agl), the engine rpm smoothly deteriorated to a total loss of power. The pilot relieved the control column back pressure, configuring the airplane in a nose-low pitch attitude in an attempt to avoid stalling and to make an off-airstrip landing. The pilot could not recall his next actions, but thought he may have unintentionally turned the fuel selector to the "off" position after the loss of power thinking he was switching to the other (more full) wing tank. The airplane collided with the thick brush off the end of the runway and nosed over, coming to rest inverted.

The pilot estimated that there were about 30 gallons of fuel in each tank. He did not know the reason for the loss of engine power but opined that he possibly leaned the engine too aggressively for the density altitude.

A post-accident examination revealed that there was minimal propeller blade damage, consistent with low or no engine power at impact. Control continuity between the cockpit's engine controls and the engine was confirmed. An external engine examination of the Continental Motors IO-550-F engine (installed in July 2010) revealed no anomalies. The integrity of the fuel system was confirmed between the fuel selector and the engine by operating the electric fuel pump and observing fuel flow from the line to the manifold. The fuel screen on the fuel control was removed and free of debris.

The top spark plugs were removed and photographed. The spark plug electrodes were undamaged, displaying a gray coloration, which the Continental representative stated was consistent with normal operation. Investigators examined the cylinder combustion chambers utilizing a lighted borescope; the cylinders all displayed normal deposits and the valves appeared to seat uniformly. The engine was turned by hand; internal continuity was established and compression and suction was confirmed an all six cylinders.

To ascertain the functionality of the powerplant, a test run of the engine was performed at the recovery facility. The propeller, damaged from the accident, was removed from the engine and a comparable propeller was installed on the engine. A fuel source was attached to the right inlet fuel line prior to entering the fuel selector. The engine was successfully started and run for over 5 minutes at various power settings from idle to about 1,500 to 1,600 rpm. A magneto check was conducted on the left and right magnetos with a minimal rpm drop on each magneto noted. The engine was shut down utilizing the mixture control lever.

During the engine run, when the auxiliary fuel pump was turned on "high," the engine ran rough and began to lose rpm until the mixture was leaned. When the fuel selector handle was changed to the "off" position, the engine would run for about 10 seconds, and then would have a temporary decline in rpm (about 5 seconds) before completely losing power.

No mechanical anomalies were noted with the recovered engine or airframe that would have precluded normal operation.

According to the airplane Owner's Manual, the auxiliary fuel pump was a split switch with two sides. If the LOW side were turned on, the fuel pump would not operate unless the engine starter was engaged. The HIGH side was used for failure of the engine driven pump. In that position, the output of the pump was dependent upon the throttle position. With the throttle at high settings, the auxiliary fuel pump output was high. When the throttle was reduced or closed, the output of the auxiliary fuel pump was designed to be reduced to prevent flooding the engine.

Aircraft and Owner/Operator Information

Aircraft Make: Cessna
Registration: N131DV
Model/Series: P206
Aircraft Category: Airplane
Amateur Built: No
Operator: On file
Operating Certificate(s) Held: None 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KLLJ, 5835 ft msl
Observation Time: 0630 MDT
Distance from Accident Site: 0 Nautical Miles
Temperature/Dew Point: 16°C
Lowest Cloud Condition: Clear
Wind Speed/Gusts, Direction: Calm / ,
Lowest Ceiling: None
Visibility:  10 Miles
Altimeter Setting: 29.95 inches Hg
Type of Flight Plan Filed: None
Departure Point: Cascade, ID (ID74)
Destination: Driggs, ID (DIJ) 

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: 2 None
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 3 None
Latitude, Longitude: 44.536667, -115.350833 (est)

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