N914NK

HISTORY OF FLIGHTOn October 9, 2016, about 1400 mountain daylight time, an experimental amateur-built Kolb Sport 600 airplane, N914NK, was substantially damaged during a forced landing in Roberts, Idaho, following a loss of engine power. The private pilot and his passenger received minor injuries. The airplane was owned and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the cross-country flight that departed a private airstrip at approximately 1400 mountain daylight time. The personal flight was destined for Joslin Field – Magic Valley Regional Airport (TWF), Twin Falls, Idaho.

The property owner reported that the pilot completed a high-speed taxi test and subsequently returned to the tie-down area at which time he told the property owner that he had encountered some vapor lock. He further communicated to the property owner that he felt comfortable with the engine's ability to develop power after the previous taxi test. The pilot had indicated to the property owner that he had experienced vapor lock during previous flights.

According to the pilot, he departed runway 24 after a successful pre-flight inspection and engine run-up. As the airplane reached approximately 100 ft above ground level (agl), the pilot perceived that the engine was losing power. He then lowered the nose and initiated a left turn teardrop maneuver to land on runway 06. The pilot engaged the airplane's auxiliary fuel pump in an effort to maintain engine power, but the propeller stopped rotating a few seconds later. Towards the end of the turn, the pilot leveled out early to land parallel to the runway, as he determined that the airplane would not reach the dirt landing strip. The airplane touched down about 200 ft south of the runway in sage brush, and subsequently impacted terrain before it nosed over and came to rest inverted, which resulted in substantial damage to the rudder. The pilot later recalled that he had discussed the possibility of vapor lock with the property owner but could not remember a previous encounter with this condition.

According to the owner of the airport property, the runway is a dirt strip about 2,200 ft long by 40 ft wide in a 24/06 runway configuration. A fly-in was held on the day of the accident with about 17 airplanes in attendance. At the conclusion of the event, the property owner walked out to the tie-down area with the accident pilot to see his airplane; the pilot and his wife then boarded the airplane. The airplane then lifted off the surface of runway 24 about 1,000 ft down the runway. During climbout the property owner observed the airplane veer to the right, and approximately 100 ft agl the airplane began a left turn, but did not appear to be accelerating. The pilot later told the property owner that the engine lost power during the turn and that he determined he would not be able to make it to runway 06. The airplane touched down on uneven terrain and flipped over inverted after it impacted a 4-foot-deep hole that contained debris. With assistance from his guests, the property owner turned the airplane over. Almost immediately, a blue colored liquid with an odor and appearance similar to 100 low lead (100 LL) aviation grade gasoline started to leak from the airplane. PERSONNEL INFORMATIONThe pilot held a private pilot certificate with ratings for single-engine land and single-engine sea. He did not possess a valid medical certificate at the time of the accident. According to the pilot, he had accumulated 10 total flight hours in the 30 days that preceded the accident, 500 flight hours in the airplane make and model, and 1,864 total flight hours in all aircraft. AIRCRAFT INFORMATIONConstruction of the airplane was completed in 2004 by the airplane's previous owner and subsequently registered to the accident pilot on May 11, 2010. The airplane was powered by a Rotax 914, turbo-charged, direct drive, air/liquid cooled, 115 hp engine. The airplane's most recent conditional inspection was completed on February 2, 2016, at which time the airplane and engine had accumulated 521.3 total flight hours. The airplane's tachometer displayed 577 hours at the time of the accident.

Postaccident examination by a Federal Aviation Administration inspector revealed that the right wing fuel tank was approximately half full, and the left fuel tank was low. According to the pilot, the recovery team drained approximately 6 gallons of fuel from the right tank, and 1 gallon from the left before the airplane was moved. He stated that he purchased 14.1 gallons of 100 LL aviation grade gasoline at Jerome County Airport, Jerome Idaho, before he departed for Roberts. The pilot normally uses automobile gasoline.

The airplane was equipped with two composite wing fuel tanks, each with a capacity of 12 gallons (11.25 gallons usable). The dihedral angle of the wings is 0° with a 1° angle of incidence. Fuel quantity was gauged by fuel senders located in each wing connected to a fuel quantity indicator in the cockpit. Each of the three tanks are inter-vented and each wing tank was vented to the outside. The airplane was not equipped with a fuel selector valve. Fuel was fed by gravity down two fuel lines in the cabin to a 0.2 gallon aluminum header tank located behind the seat back. The fuel flowed to a fuel strainer, through a fuel shutoff valve, and then to a main boost pump and an auxiliary boost pump before it arrived at the engine. Both pumps were actuated by separated switches at the instrument panel; the main boost pump was located on the pilot's side and the auxiliary boost pump on the passenger's side. The design allowed fuel to be fed from both tanks simultaneously, and there was no provision for the pilot to make a fuel tank selection. The airplane was equipped with a fuel return line that routed unused fuel to the wing fuel tanks to prevent fuel vapor lock.

An examination of the fuel lines did not reveal any obstructions or preaccident breaches.

The airplane was equipped with a Garmin Area 500 GPS unit. The unit recorded multiple flights prior to the accident flight; however, the accident flight was not recorded. The unit data showed a flight from KJER to U56, which is about 10 nm east of Roberts and a total distance of 127 miles over 1.2 hours of flight time. METEOROLOGICAL INFORMATIONThe 1353 recorded weather observation at Idaho Falls Regional Airport, Idaho Falls, Idaho, about 14 nm southeast of the accident site, included wind from 210o true at 15 knots with gusts to 22 knots, visibility 10 statute miles, clear skies, temperature 21o C, dew point 01o C, and an altimeter setting of 30.07 inches of mercury. AIRPORT INFORMATIONConstruction of the airplane was completed in 2004 by the airplane's previous owner and subsequently registered to the accident pilot on May 11, 2010. The airplane was powered by a Rotax 914, turbo-charged, direct drive, air/liquid cooled, 115 hp engine. The airplane's most recent conditional inspection was completed on February 2, 2016, at which time the airplane and engine had accumulated 521.3 total flight hours. The airplane's tachometer displayed 577 hours at the time of the accident.

Postaccident examination by a Federal Aviation Administration inspector revealed that the right wing fuel tank was approximately half full, and the left fuel tank was low. According to the pilot, the recovery team drained approximately 6 gallons of fuel from the right tank, and 1 gallon from the left before the airplane was moved. He stated that he purchased 14.1 gallons of 100 LL aviation grade gasoline at Jerome County Airport, Jerome Idaho, before he departed for Roberts. The pilot normally uses automobile gasoline.

The airplane was equipped with two composite wing fuel tanks, each with a capacity of 12 gallons (11.25 gallons usable). The dihedral angle of the wings is 0° with a 1° angle of incidence. Fuel quantity was gauged by fuel senders located in each wing connected to a fuel quantity indicator in the cockpit. Each of the three tanks are inter-vented and each wing tank was vented to the outside. The airplane was not equipped with a fuel selector valve. Fuel was fed by gravity down two fuel lines in the cabin to a 0.2 gallon aluminum header tank located behind the seat back. The fuel flowed to a fuel strainer, through a fuel shutoff valve, and then to a main boost pump and an auxiliary boost pump before it arrived at the engine. Both pumps were actuated by separated switches at the instrument panel; the main boost pump was located on the pilot's side and the auxiliary boost pump on the passenger's side. The design allowed fuel to be fed from both tanks simultaneously, and there was no provision for the pilot to make a fuel tank selection. The airplane was equipped with a fuel return line that routed unused fuel to the wing fuel tanks to prevent fuel vapor lock.

An examination of the fuel lines did not reveal any obstructions or preaccident breaches.

The airplane was equipped with a Garmin Area 500 GPS unit. The unit recorded multiple flights prior to the accident flight; however, the accident flight was not recorded. The unit data showed a flight from KJER to U56, which is about 10 nm east of Roberts and a total distance of 127 miles over 1.2 hours of flight time. WRECKAGE AND IMPACT INFORMATIONEngine and Fuel System Examinations

The engine was examined at a recovery facility in Idaho by a representative of the engine manufacturer under the supervision of the NTSB Investigator-in-Charge. The inspection included an examination of the carburetors and two engine test runs.

According to the airplane's maintenance logbooks, both carburetors were removed on May 12, 2016, and sent to California Power Systems for overhaul. The logbook entry that captured the removal of the carburetors was recorded at a total tachometer time of 537.1 total flight hours, 38 flight hours before the ...