KOTZEBUE, AK, USA
N73188
Cessna 207A
The certificated airline transport pilot departed on a flight to a remote village about 37 miles away. The trip was the first since an annual inspection had been completed the day before. The pilot departed with fuel only in the left wing tank. The right wing tank was empty. About 35 minutes later, the pilot was on a return flight to his original departure airport that was within Class E airspace. During the pilot's absence, the airport visibility had decreased to 1 1/2 mile. Instrument meteorological conditions, and special VFR procedures were in use. A 'MAYDAY' was heard over the common traffic advisory frequency, and was monitored by the local flight service station. The voice of the pilot was recognized as the accident pilot. Search personnel found the airplane on a flat area of a frozen, snow-covered lagoon. The weather at the accident site was described as fog, with flat lighting conditions. The wreckage path was oriented away from higher terrain around the destination airport which is located on a peninsula. The airplane had crashed in a nose down attitude, and came to rest inverted. The engine separated completely from the airframe. An examination of the engine revealed fuel throughout, and mechanical continuity. The vacuum pump's internal support post, on which the internal block rotated, was found fractured through 70 percent of its diameter from fatigue, the remaining portion of fracture was overstress. The airplane was equipped with a standby vacuum system. An examination of the airframe located a combination screwdriver in the left wing. The handle was shattered. No flight control cable impingement was observed.
HISTORY OF FLIGHT On April 14, 1999, about 0930 Alaska daylight time, a Cessna 207A airplane, N73188, was destroyed after crashing on an ice and snow-covered lagoon, about 10.3 nautical miles east of Kotzebue, Alaska. The airplane was being operated as a visual flight rules (VFR) scheduled domestic flight under Title 14, CFR Part 135, when the accident occurred. The airplane was operated as Flight 303X, by Village Aviation Inc., doing business as Camai Air. The flight was an extra section to scheduled Flight 303. The certificated airline transport pilot, the sole occupant, received fatal injuries. Instrument meteorological conditions prevailed in the area of the accident. A VFR flight plan was filed. At 0845:44, the pilot contacted the In-Flight One position of the Kotzebue Flight Service Station (FSS) on a frequency of 122.2 MHz. The pilot filed a VFR flight plan to Noorvik, Alaska, with a return to Kotzebue. His planned time en route was one hour, and he said he had three hours of fuel. The pilot departed with cargo consisting of U.S. mail, and opened his flight plan at 0847:19. The distance from Kotzebue to Noorvik is 37 nautical miles, and the operator said the flight usually takes 28 minutes. The weather conditions at Kotzebue included a visibility of 3 miles in light snow and mist. After the flight departed Kotzebue, the weather conditions deteriorated below basic VFR minimums. At 0908, a special weather observation at Kotzebue included a visibility of 1.5 miles in light snow and mist. At an estimated time of 0920, the airplane departed the Robert Curtis Memorial Airport, Noorvik, Alaska, with no mail or cargo for the return flight to Kotzebue. There are no weather reporting facilities at Noorvik. Instrument meteorological conditions prevailed at Kotzebue as the accident flight was returning from Noorvik. Special VFR (SVFR) clearances, upon request of pilots, were being granted by Kotzebue FSS personnel for operations in the Class E airspace around the Kotzebue airport. At 0928:48, Kotzebue FSS personnel and other pilots monitoring the Kotzebue common traffic advisory frequency (CTAF) of 123.6 MHz, heard a radio call of "mayday, mayday, mayday." The pilot's voice was identified by those hearing the radio call. At 0933:48, aircraft in the area reported hearing an emergency locator transmitter (ELT) signal. The ELT was not heard at the Kotzebue FSS. Ground search personnel departed Kotzebue on snow machines, and located the wreckage on the Hotham Inlet, about 1055. The accident site is about 1/2 nautical mile east of the shoreline of the Baldwin Peninsula. The accident occurred during the hours of daylight at latitude 66 degrees, 50.908 minutes north, and longitude 162 degrees, 09.965 minutes west. CREW INFORMATION The pilot held an airline transport pilot certificate with airplane single-engine land, single engine sea, multiengine land, and multiengine sea ratings. He also held commercial pilot privileges with a rotorcraft helicopter rating. The most recent second-class medical certificate was issued to the pilot on April 6, 1998, and contained the limitation that the pilot must have available glasses for near vision. No personal flight records were located for the pilot, and the aeronautical experience listed on page 3 of this report was obtained from the operator's records. The pilot was hired on August 14, 1998. Prior to joining the company, he accrued extensive 14 CFR Part 135 experience flying in Alaska,. The pilot completed an airman competency/proficiency check flight under Title 14 CFR Part 135.293 (Initial and Recurrent Testing), and 135.299 (Pilot-in-Command Line Check), with the chief pilot for the operator in a Cessna 207 airplane on August 21, 1998. A CFR Part 135.299 (Instrument Proficiency Check) check flight was not performed, nor was it required. The chief pilot noted that the pilot demonstrated basic IFR competency. According to company records, the pilot's total aeronautical experience exceeded 10,000 hours, of which over 7,800 hours were accrued in the accident airplane make and model. In the preceding 90 and 30 days prior to the accident, the company listed a total of 175 and 66 hours respectively. The accident flight was the pilot's first flight since he last flew on April 10, 1999. AIRCRAFT INFORMATION An annual inspection of the airframe and engine had been completed the day before the accident. At that time, the airplane had accumulated a total time in service of 16,789.2 hours. The airplane then flew an additional .7 hours before the accident. During the annual inspection, the right wing fuel tank was drained of about 30 gallons of fuel to replace a fuel line. The engine was rebuilt by the Teledyne Continental Motor Company on October 15, 1997. It was installed on the accident airplane by the operator on February 13, 1998. At the time of the annual inspection on April 13, 1999, the engine had accrued 1,179.2 hours since it was rebuilt. It then accrued an additional .7 hours before the accident. The airplane is equipped with two fuel tanks, one mounted in each wing. Each tank has a capacity of 40 gallons, with 3.5 gallons as unusable fuel. Fuel cannot be used from both tanks simultaneously. The station manager reported the pilot did not place any fuel into the right wing fuel tank of the airplane before departure to Noorvik. The left wing fuel tank contained an estimated 30 gallons of fuel. The airplane was equipped with basic instruments for flight in instrument conditions. The engine was equipped with a dry air pump that provided suction power for the airplane's attitude indicator, and the directional indicator. An Airborne dry pump, overhauled by Rapco Inc., was installed on the engine by the operator on October 19, 1998. At the time of the accident, the pump had accrued 634.0 hours. During the annual inspection on the day before the accident, the operator's inspection run-up sheet contained a notation that the vacuum pressure was 5.1 inches. The normal suction range is between 4.6 and 5.4 inHg. In the event of a loss of suction from the engine driven vacuum pump, the airplane was equipped with a redundant, standby vacuum system from Precise Flight Inc., Bend, Oregon. The system was installed on March 2, 1990, under Supplemental Type Certificate (STC) number SA216NM. The system consisted of a valve installed in a hose between the engine intake manifold, and the airplane's attitude instruments. A cable was installed between the valve and the instrument panel. The valve was rotated to the open position by pulling on an instrument panel knob. An "instrument source/pump inop warning" light emitting diode (LED) was also installed in the instrument panel to alert the pilot of a primary vacuum system failure. METEOROLOGICAL INFORMATION The closest official weather observation station is located at Kotzebue. Instrument meteorological conditions existed at the airport as the pilot was returning from Noorvik. At 0908, a special weather observation was reporting in part: Wind, 030 degrees (true) at 7 knots; visibility, 1.5 statute miles in light snow and mist; clouds and sky condition, 2,100 feet scattered, 3,600 feet overcast; temperature, 12 degrees F; dew point, 8 degrees F; altimeter, 30.10 inHg. Search personnel at the accident scene reported overcast clouds and fog. Flat lighting conditions prevailed with little definition or contrast between the horizon and the ground. COMMUNICATIONS Review of the air-ground radio communications tapes maintained by the FAA at the Kotzebue FSS facility, revealed the pilot communicated with the position of In-Flight One when he filed a VFR flight plan. The FAA found no record indicating the pilot received a weather briefing. A transcript of the air to ground communications between the airplane and the Kotzebue FSS is included in this report. Continuous data recording (CDR) radar data from the Kotzebue Air Route Traffic Control Center radar site was reviewed by National Transportation Safety Board investigators to determine the flight track of the accident airplane. A radar track from an aircraft with a VFR transponder code of 1200, was located beginning at 0921:29, about 10.4 miles west of Noorvik. The radar track continued in a westerly direction. The radar track stopped at 0929:29, about 1.2 miles west of the accident scene. The last radar return, and the accident location, lie within the Kotzebue Airport Class E airspace. A copy of the radar data is included in this report. AERODROME AND GROUND FACILITIES The Ralph Wien Memorial Airport at Kotzebue is equipped with a hard-surfaced runway on a 080 to 260 degree magnetic orientation. Runway 26 is 5,900 feet long by 150 feet wide, and is equipped with high intensity runway lights, runway end identifier lights, and a visual slope indicator system. A second gravel runway, located south of runway 26, is oriented on a 170 to 350 degree magnetic orientation. Runway 17 is 3,896 feet long by 90 feet wide, and is equipped with medium intensity runway lights. The airport is served by both precision and nonprecision instrument approach procedures. The airport lies within Class E airspace. The eastern edge of the airspace is located about 11 miles east of the Kotzebue airport. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board investigator-in-charge (IIC), an FAA airworthiness inspector from the Fairbanks Flight Standards District Office, and an Alaska state trooper, went to the accident site on April 15, 1999. The trooper said about 4 inches of snow had fallen at the wreckage site since the accident. A depression in the snow, followed by a path of wreckage debris to the wreckage point of rest, was observed on a magnetic heading of 037 degrees. (All heading/bearings noted in this report are oriented in relation to magnetic north.) The first observed point of impact was a semi-circular depression in the snow, about three feet wide and eight feet long. Two smaller impressions were observed on either side of the main depression. The first portion of the airplane located along the wreckage path was the right side fuselage step, about 30 feet beyond the first observed point of impact. About 20 feet beyond the step was the nose wheel vibration dampner. Additional portions of the airplane were found along the wreckage path, and included, in the order observed: windshield fragments, wing lift strut fairing fragments, the upper engine cowling, the right wing tip fairing, the right front cabin door, the nose wheel strut, portions of instrument panel, the forward section of the right side cargo door, the left front cabin door, fragments of the engine mount, nose cargo door and nose wheel, and portions of the nose/engine keel structure. The directional gyro, the attitude gyro, the turn coordinator, the altimeter, and the vertical speed indicator, were broken out of the instrument panel. The main fuselage wreckage came to rest about 300 feet from the first observed point of impact. The airplane was lying inverted with the left wing lying flat along the surface of the snow. The left wing was positioned about 45 degrees aft of its normal position. The wing spar carry-through was torn from the fuselage. The lift strut was attached to the wing, but separated from the fuselage. The left wing displayed spanwise aft, vertical/flat crushing, of the leading edge from the pitot tube to the outboard edge of the flap. Forty-five degree aft flat crushing and folding of the leading edge was evident from the flap to the tip. The wing tip was attached to the wing, along with the position light and strobe. Examination of the left wing position bulb filament revealed the filament was broken about mid-span. The visible portion of the filament was tightly coiled. The aileron was attached to the wing, but buckled in a U-shape, with aft crushing and upward curling of the trailing edge. The flap remained attached to the wing. Fuel was found in the left wing fuel tank. The right wing was fractured at the inboard end and was standing vertically with the wing tip up, with the leading edge oriented 90 degrees to the fuselage in an inboard direction. The leading edge had extensive spanwise leading edge aft and upward crushing and buckling along a 45 degree angle from the trailing edge of the wing tip, to about the inboard end of the aileron attach point. The aileron and flap remained attached to the wing. The lift-strut was attached to the wing. The lift-strut was attached to the fuselage at its lower attach point, but had a 120 degree U-shaped bend, about one foot from the fuselage. An area of oil residue was found splattered on the leading edge of the right wing, and along the upper and lower surface, about the lift-strut attach point. Evidence of oil streaking was not found on the belly of the fuselage, the windshield or upper surface of the fuselage, the empennage, the inside of the engine cowling, or on the firewall. The upper left corner of the fuselage was crushed in a downward direction, almost to the bottom of the windshield. The cabin area, aft of the trailing edge of the wing was buckled and distorted. The aft section of the right side cargo door remained attached to the fuselage. The empennage, just forward of the vertical stabilizer attach point, was twisted and buckled to the left. Both horizontal stabilizers were free of any major damage. The vertical stabilizer was curled to the left at its aft, upper edge. The rudder was curled to the left near the top. The elevator and trim tab remained attached to the horizontal stabilizer and was free of any major damage. Examination of the rear fuselage position bulb filament revealed the filament was intact and tightly coiled. The flap jackscrew actuator was extended about 3/4 inch. According to the airplane manufacturer, the flap jackscrew extension corresponded to a near zero flap condition. The elevator trim tab actuator was found extended about 2 1/4 inches. The trim tab actuator corresponded to about a 25 degree tab up (nose down) setting. The normal range of trim tab extension is from 25 degrees tab up, to 5 degrees tab down. The main landing gear remained attached to the fuselage. The right main gear strut was displaced aft. The forward face of the right main landing gear strut fairing had aft vertical/flat crushing. The inboard area of the forward face of the left main landing gear strut fairing had similar aft flat crushing. The fuselage, forward of the front door posts and including the instrument panel, firewall, and nose baggage area, was buckled, crushed, and torn in a downward direction. The bottom portion of the fuselage skin, just aft of the nose wheel well had a black smudge. Due to impact damage, the flight controls could not be moved by their respective control mechanisms. Fuel was contained in the fuselage gascolator. The gascolator screen had several specks of contaminants. The fuel selector was on the left tank. The propeller hub assembly separated from the engine crankshaft about 2 inches inboard from the propeller flange. The propeller was located about 250 feet from the initial observed point of impact. The fracture surface of the propeller/crankshaft had multiple, 45 degree angled shear faces. All three propeller blades were retained in the hub, but were loose and rotated within the hub. One propeller blade had about 90 degree aft bending and aft curling at the tip. The leading edge had file marks, a gouge about 10 inches inboard from the tip, but was generally free of damage. Minor paint removal was evident about 8 inches inboard from the tip, and minor scuffing along the upper surface of the blade. The second blade displayed leading edge file marks, slight aft bending, and slight aft curling at the tip. Spanwise scuffing and scratching was observed about two inches inboard from the tip. The third blade had an aft 90 degree bend, about 8 inches inboard from the tip. The blade had slight torsional twisting, and minor scuffing at the tip. The leading edge had file marks, but no chordwise scratching or gouging. The engine separated from the fuselage, and w
The pilot's continued VFR flight into instrument meteorological conditions, spatial disorientation, and an inadvertent stall. Factors in the accident were weather conditions consisting of snow and mist, and flat lighting conditions.
Source: NTSB Aviation Accident Database
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