Anniston, AL, USA
N56920
Boeing Stearman PT-17
According to witnesses, the airplane was circling a golf course and then began to climb, shortly after climbing to an undetermined altitude, the airplane went into a nose down slow spin and impacted into a stand of trees. On July 22, 2001, the other two owners of the airplane had inspected the control surface lock (gust Lock) by moving it from the lock/unlock position several times. The reason for the inspection was in preparation for the upcoming annual inspection. According to the owners, they could not recall if they had stowed it in the unlock position when they had finished their inspection. During the course of flight control examination it was found that the handle for the operation of the control surface lock, which secures the rudder, ailerons and elevator, was installed in each cockpit, and was found in the locked position. The locking handle in the forward cockpit area was found separated from its mounting bracket. When placed in its proper orientation to the fracture surface it was found to be in the locked position. Injuries sustained by the pilot rated passengers left arm were consistant with the damage to the forward control lock. The aft control lock was found intact and in the down and locked position. According to the Pilots Flight Operating Instructions, during pre-flight inspection, the control lock should be in the lock position during startup and taxi, and disengaged and stowed into the unlock position just prior to takeoff.
HISTORY OF FLIGHT On July 24, 2001, at 1030 central daylight time, a Boeing Stearman PT-17, N56920, collided with the ground at the Indian Oaks Golf Course, in Anniston, Alabama. The airplane was registered to a partnership and operated by one of the partners who was an airline transport pilot (ATP) under the provisions of Title 14 CFR Part 91, and visual flight rules. Visual meteorological conditions prevailed and no flight plan was filed for the local flight. The pilot and pilot rated passenger received fatal injuries and the airplane was destroyed. The airplane departed Anniston Metro Airport, Anniston, Alabama, at 1015. According to witnesses, the airplane was circling the golf course and then began to climb, shortly after climbing to an undetermined altitude, the airplane went into a nose down slow spin and impacted into a stand of trees. PERSONNEL INFORMATION The pilot was certificated as a airline transport pilot for airplane single and multiengine land, helicopter, and was certified as a flight instructor for instrument airplane single and multiengine land and helicopter. In addition, the pilot was type rated in the following aircraft; BE-200, BE-300, BH-204, CE-500, DC-3 and the Lear Jet. The pilot reported having 20,300 hours of total civilian hours on his last medical examination. The pilot's most recent first class medical was issued on October 24, 2000 with the restriction to wear corrective lenses. The pilot's logbook was not located during the course of the investigation. The pilot rated passenger was certificated as a private pilot for airplane single, multiengine land Instrument airplanes. The pilot rated passenger reported having 2,250 hours of total civilian hours on his last medical examination. The pilot rated passengers most recent third class medical was issued on October 6, 1999, with the restriction to wear corrective lenses. The pilot rated passengers logbook was not located during the course of the investigation. AIRCRAFT INFORMATION The pilot and two other individuals owned the airplane as a partnership. The PT-17 airplane is a two-place open biplane, manufactured by Boeing Airplane Company and powered with a Continental 220 horse-power air-cooled radial engine coupled to an eight-foot six inch diameter wooden blade, fixed pitch propeller. The wings are of internally braced wooden construction, with aluminum alloy leading and trailing edges. Both the empennage and fuselage are welded tubular steel structures, provided with aluminum alloy fairing. The ailerons are a riveted structure of formed aluminum alloy. With the exception of the engine and fuselage cowling, the wings, fuselage, empennage, and ailerons are fabric covered. The landing gear is of the fixed cantilever type with hydraulic brakes. A review of the maintenance records found that the airplane had been given a annual inspection on July 14, 2000 and had accumulated 15 hours of flight time since that inspection. On July 22, 2001, the other two owners of the airplane had inspected the control surface lock (gust Lock) by moving it from the lock/unlock position several times. The reason for the inspection was in preparation for the upcoming annual inspection. According to the owners, they could not recall if they had stowed it in the unlock position when they had finished their inspection. However, according to the Pilot Operating Instructions, during pre-flight inspection, the control lock should be in the lock position during startup and taxi, and disengaged and stowed into the unlock position just prior to takeoff. METEOROLOGICAL INFORMATION Visual meteorological conditions prevailed at the time of the accident. According to the weather observation report from the Anniston Automated Flight Service Station the weather at 0953 was reported as sky clear of clouds, ceiling none, visibility 10 statute miles, altimeter 29.97 hg, temperature 29 degrees Celsius, dew point 22 degrees Celsius, wind 070 degrees at 4 knots. WRECKAGE AND IMPACT INFORMATION Examination of the engine found that it was a Continental R-670-5, radial engine with a rated horse power of 220. The engine was found partially attached to the engine mounts with the propeller facing skyward with the front of the engine packed with dirt. The wooden propeller blades were separated just outboard of the propeller hub on one blade and cracked and splintered out to the tip on the other blade. The propeller remained attached to the engine. Examination of the engine found no pre-existing discrepancies that would have prevented normal operation prior to impact. Examination of the airframe found that it had impacted the ground in a nose down attitude and came to rest inverted on the side of a hill. There was damage noted to tree limbs adjacent to the wreckage and no direction of flight could be established. Significant crushing was noted in the forward cockpit area. The left and right upper and lower wings remained partially attached but the main spars were broken. The right wings were found folded aft and were lying over the forward cockpit area. The left wings were found crushed from the leading edge aft, and the top of the rudder was found folded 90 degrees to the left just above its attach point to the vertical stabilizer. Examination of the aileron and elevator controls found the these control surfaces are controlled by inter-connected control sticks in each cockpit, through a series of push-pull tubes and bell cranks. Continuity of these push-pull tubes and bell cranks was established to the aft cockpit however continuity ended in the forward cockpit due to separation of the push-pull tubes during the impact sequence. During the course of flight control examination it was found that the handle for the operation of the control surface lock, which secures the rudder, ailerons and elevator, was installed in each cockpit, and was found in the locked position. The locking handle in the forward cockpit area was found separated from its mounting bracket. When placed in its proper orientation to the fracture surface it was found to be in the locked position. Additionally, the pilot rated passengers left arm sustained injuries consistent with the damage noted to the broken control lock. The aft control lock was found intact and in the down and locked position. According to the pilot operating handbook you lock the controls by "pushing down on the control lock handle, neutralize the rudder pedals and stick; push the stick slightly forward, and while holding the controls in this position, turn the locking handle down and allow the latch pin to snap into place. If the latch pin does not seat readily, a slight movement of the rudder pedals will assist in lining up the pin for engagement". Examination of the locking system found that if the control lock was in the stowed position it would require deliberate movement of the locking handle by either occupant to disengage it from its stowed position and place it in the locked position. However, according to the owners of the airplane, if left in the neutral position the handle could be pushed inadvertently by either the front or rear occupant into the locked position. This action would go unnoticed by either pilot, and would lock the controls into a nose down position. MEDICAL AND PATHOLOGICAL INFORMATION On July 25, 2001, post mortem examination of the pilot and the pilot rated passenger were conducted by Dr. Joseph H. Embry, MD, JD. Regional Medical Examiner, Alabama Department of Forensic Sciences Birmingham, Alabama. The cause of death was listed as multiple blunt force trauma for both occupants. On August 8, 2001, a toxicology examination of the pilot was conducted by the FAA Toxicology Research Laboratory. The examination revealed no carbon monoxide or cyanide detected in the blood, no ethanol detected in the urine. However, there was metoclopramide detected in the blood and liver. (Metoclopramide is a prescription commonly used to control acid reflux.) ADDITIONAL INFORMATION Further examination of the pilot operating handbook found the pre-flight check list with states in part that upon entering the pilot's compartment check before all flights, 1) Ignition switch - off, 2) Parking brake - on, 3) Controls - Locked, 4) Throttle - Closed, 5) Mixture control - full lean, 6) Carburetor air heater control - cold. According to the pre-flight check list the controls remain locked until just prior to takeoff. At take-off the check list states 1) Flight Controls: - "Unlocked" (handle up). On July 25, 2001 the wreckage was released to the owner’s at 17 Lanier Place, Anniston, Alabama 36201.
The inadvertent activation of the flight control gust locks by the pilot rated passenger that resulted in the loss of control inflight. Contributing was the pilot in commands failure to follow the airplane's pre-flight inspection check list.
Source: NTSB Aviation Accident Database
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