N777PH

HISTORY OF FLIGHTOn November 4, 2017, at 1728 central daylight time, a Beech V35B (Bonanza) airplane, N777PH, impacted terrain during approach to Alva Regional Airport (AVK), Alva, Oklahoma. The pilot and flight instructor were fatally injured, and the airplane was destroyed. The airplane was registered to the pilot who was operating it under the provisions of Title 14 Code of Federal Regulations Part 91 . Day visual meteorological conditions prevailed and no flight plan was filed for the local instructional flight, which departed AVK about 1710.

According to a state trooper who spoke with the pilot at an emergency room, the pilot and flight instructor flew to Cherokee Municipal Airport, Cherokee, Oklahoma, for a practice approach and were returning to AVK when the accident occurred. The pilot stated that he and the flight instructor noticed that the left engine cowling had "popped up" during the approach to AVK. Subsequently, the flight instructor assumed control of the airplane. About 1/2 mile before reaching the runway 18 threshold, the airplane collided with trees and a power line, which were about 40 ft higher than the airport's elevation. The airplane came to rest inverted on its left side, and a postcrash fire ensued.

The pilot and flight instructor egressed the airplane with their clothes on fire. The flight instructor was unable to move away from the wreckage during the postcrash fire and subsequent explosion and died at the accident site. The pilot climbed a hill next to the airplane, and responders helped him extinguish his burning clothes. The pilot was taken to an emergency room near the accident site and subsequently transported to the Integris Burn Center, Oklahoma City, Oklahoma, with burns on over 80% of his body. The pilot died on November 7, 2017, from the injuries he sustained.

A segment of the final approach was captured by five home surveillance video cameras, and a video study was conducted, which confirmed that the left engine cowling was open during the final approach. During a 12-second period that corresponded to 1,500 ft of ground track, the airplane descended from about 250 ft to about 100 ft above ground level, and the airspeed decreased from 76 ± 4 knots to 71 ± 4 knots. The landing gear was extended and the flap positions could not be determined. At the end of the 12-second period, as the airplane approached the accident site, the descent rate increased to about 1,000 ft per minute. PERSONNEL INFORMATIONFlight Instructor

The flight instructor, age 61, held commercial pilot and flight instructor certificates with airplane single- and multiengine land and instrument ratings. On his most recent Federal Aviation Administration (FAA) airman medical application, dated May 15, 2017, the flight instructor reported 2,529 hours of civil flight experience with 110 hours in the previous 6 months. On an insurance application dated May 1, 2017, the flight instructor reported 11,456 hours of total flight experience, which included his military flight experience. The flight instructor owned a Beech Bonanza airplane and frequently trained in them.

Pilot

The pilot, age 39, held a private pilot certificate with an airplane single-engine land rating. The pilot was issued a third-class medical certificate with no limitations on September 10, 2014. A logbook review revealed that the pilot had accumulated 231 flight hours as of June 1, 2017. The pilot had recently purchased the airplane and chose to receive training from the flight instructor based on the instructor's strong teaching reputation with Bonanza airplanes. The accident occurred during the pilot's first training flight and second flight overall in the accident airplane. AIRCRAFT INFORMATIONThe airplane, serial number D-9544, was issued a standard airworthiness certificate on October 17, 1973. The airplane was equipped with a Continental IO-520-BA10 engine, serial number 241368-R, and a three-bladed McCauley propeller. The airplane's last annual inspection occurred on May 1, 2017, at a total airframe time of 1,927.7 hours. A second control yoke was installed before the accident flight.

In 1979, a Robertson Short Takeoff and Landing (STOL) system was installed in accordance with Supplemental Type Certificate (STC) SA503NW. The modification included removal of the ailerons; installation of full-span, single-slotted flaps; and installation of a spoiler roll control system. Flap positions for the STC modification were 0°, 15°, and 30°. The airplane was one of only three Bonanza airplanes modified by the STC.

A handwritten list of airplane discrepancies, with penmanship matching entries in the pilot's logbook, was found in the pilot's hangar. One of the listed discrepancies was "cowling latch - pilot's side rear spring."

A review of cowling latch part information indicated that each latch had two springs. One spring returned the latch jaws to the closed position when the bayonet fittings were pushed into the latch, and one spring exerted tension on the latch mechanism.

The airplane flight manual contained the following information concerning the engine cowlings:

The Bonanza is equipped with Hartwell latch mechanisms on the right and left upper engine cowling for quick and easy access to the engine compartments without the aid of tools. Each cowl latch (two per cowl) is locked and released by a single recessed handle located in the lower cowling panel on each side of the engine. To close the cowling, lower the cowling to the closed position with the handle in the prelatch position. The handle has three positions: flush with the fuselage is latched; held fully forward is unlatched; approximately 90° to the fuselage is prelatch (ready to close cowl). An audible click denotes the bayonet fittings, located forward and aft on the upper cowl, sliding into the latch safety catch. The cowl is locked by moving the latch handle to the full recessed position. The security of the forward latches can be checked by pulling out on the check tab attached to the lower forward edge of the upper cowling. If the cowling can be moved after latching, open the cowling, check the latch alignment and re-latch.

A video of an exemplar engine cowling being shut and photographs of an exemplar engine cowling, latches, and bayonet fittings, are included in the docket for this investigation.

In 1995, Beechcraft released a Safety Communique, which stated, in part, the following:

Beech Aircraft Corporation continues to receive reports of accidents following the opening of a cabin door, baggage door, engine cowling, or fuel cap during takeoff or flight. In many cases, the pilot failed to make certain the cabin door, baggage door, engine cowling, or fuel cap was properly latched and secured during pre-flight. In each accident, the pilot also failed to properly control the airplane and the airplane stalled at low altitude. THESE ACCCIDENTS SHOULD NOT HAPPEN!

If a cabin door, baggage door, or engine cowling is not properly latched and secured, it will usually open during takeoff immediately before or at rotation, although there have been reports of unlatched doors and engine cowlings opening in cruise flight. On some models, additional noise is to be expected. Do not permit yourself to be distracted. ALWAYS MAINTAIN CONTROL OF THE AIRPLANE. AIRPORT INFORMATIONThe airplane, serial number D-9544, was issued a standard airworthiness certificate on October 17, 1973. The airplane was equipped with a Continental IO-520-BA10 engine, serial number 241368-R, and a three-bladed McCauley propeller. The airplane's last annual inspection occurred on May 1, 2017, at a total airframe time of 1,927.7 hours. A second control yoke was installed before the accident flight.

In 1979, a Robertson Short Takeoff and Landing (STOL) system was installed in accordance with Supplemental Type Certificate (STC) SA503NW. The modification included removal of the ailerons; installation of full-span, single-slotted flaps; and installation of a spoiler roll control system. Flap positions for the STC modification were 0°, 15°, and 30°. The airplane was one of only three Bonanza airplanes modified by the STC.

A handwritten list of airplane discrepancies, with penmanship matching entries in the pilot's logbook, was found in the pilot's hangar. One of the listed discrepancies was "cowling latch - pilot's side rear spring."

A review of cowling latch part information indicated that each latch had two springs. One spring returned the latch jaws to the closed position when the bayonet fittings were pushed into the latch, and one spring exerted tension on the latch mechanism.

The airplane flight manual contained the following information concerning the engine cowlings:

The Bonanza is equipped with Hartwell latch mechanisms on the right and left upper engine cowling for quick and easy access to the engine compartments without the aid of tools. Each cowl latch (two per cowl) is locked and released by a single recessed handle located in the lower cowling panel on each side of the engine. To close the cowling, lower the cowling to the closed position with the handle in the prelatch position. The handle has three positions: flush with the fuselage is latched; held fully forward is unlatched; approximately 90° to the fuselage is prelatch (ready to close cowl). An audible click denotes the bayonet fittings, located forward and aft on the upper cowl, sliding into the latch safety catch. The cowl is locked by moving the latch handle to the full recessed position. The security of the forward latches can be checked by pulling out on the check tab attached to the lower forward edge of the upper cowling. If the cowling can be moved after latching, open the cowling, check the latch alignment and re-latch.

A video of an exemplar engine cowling being shut and photographs of an exemplar engine cowling, latches, and bayonet fittings, are included in the docket for this investigation.

In 1995, Beechcraft released ...