SEA05FA022

After liftoff from a touch-and-go landing, the aircraft climbed to about 100 feet above the ground, whereupon the pilot transmitted that he had a problem. Although he did not specify what the problem was, the aircraft was seen entering what initially appeared to be a pilot-initiated left turn. Soon thereafter the aircraft's bank angle and pitch angle increased, and it subsequently descended into a commercial aircraft post-production parking ramp. Just prior to impact, the aircraft's bank angle had increased to more than 80 degrees, and it's nose was approximately 40 degrees below the horizon. Both a photo from a ramp security camera, and a post-accident inspection revealed that the flaps where in the full-down position at impact. Further investigation revealed that the flap latch inner pivot bushing and the rivet that retained it were missing. This resulted in the flap latch becoming detached from its pivot point within the handle, leaving no way for it to be disengaged from the flaps full-down notch in the flap ratchet plate, thus negating the possibility of flap retraction. It was also determined that the holes in the sides of the flap handle, wherein the inner pivot bushing rests, had both worn to an oblong shape. One of the holes, at the point of its greatest diameter, had worn to .337 inch oversize.

History of flight

On December 5, 2004, at 1228 Pacific standard time, a Cessna 185F, N532PC, impacted the Boeing Aircraft Company 737 post-production parking ramp soon after lifting off from a touch-and-go landing at Renton Municipal Airport, Renton, Washington. The private pilot, who was the sole occupant, received fatal injuries, and the aircraft, which was owned and operated by the pilot, was destroyed by the impact sequence and the subsequent fire. The local 14 CFR Part 91 pilot proficiency flight, which began about 40 minutes prior to the crash, was being operated in visual meteorological conditions. There was no report of an ELT activation. No flight plan had been filed.

According to family members and a close acquaintance, it had been at least about six or seven weeks since the pilot had last flown his aircraft, and he had come to the airport on the day of the accident with the intention of practicing his takeoffs and landings to maintain his proficiency and currency. According to the tower controller who was on duty at the time, the pilot called for taxi clearance from the north tower parking area at 1145. At that time the pilot advised the tower that he had information Echo, and that he would be staying in the traffic pattern. He was then cleared to taxi to Runway 15, and after a short period of time at the run-up area adjacent to the approach end of Runway 15, the pilot called for a takeoff clearance. After takeoff, the pilot stayed in the traffic pattern and executed five or six touch-and-go landings. On the last touch-and-go, the aircraft touched down on the runway surface, rolled an undetermined distance, and then lifted back into the air. Up to that point, neither the tower control nor any witnesses had noticed anything out of the ordinary with the aircraft's flight profile or the pilot's transmissions. But, about the time the aircraft reached an altitude of 100 feet above ground level (AGL), the pilot transmitted "I've got a problem here." The pilot did not give a specific indication as to what the problem was, nor did he make any further transmissions. The controller therefore immediately cleared the pilot to land on any runway, and the aircraft was seen banking to the left, in what appeared to most of the witnesses to be a normal pilot-initiated turn, although at a very low altitude. The aircraft's bank angle continued to increase, its pitch attitude initially increased and then decreased, and it susequently descended into the tarmac about 400 feet east of the runway centerline. According to a photo from a Boeing tarmac security camera, when the aircraft was approximately one wing span above the surface, it was in a left bank of more than 80 degrees, its nose was approximately 40 degrees below the horizon, and it had completed about 135 degrees of turn from the runway heading. The camera also revealed that the aircraft's flaps were deployed, although the photo was not clear enough to determined the setting they were at. After the aircraft impacted the tarmac surface between two Boeing 737's, it slid approximately 120 feet before impacting a jet-blast fence, whereupon it burst into flames.

Meteorological information

According to the 1153 surface aviation weather observation at the Renton Airport, the winds were 190 degrees at six knots, the visibility was 10 statute miles, there was a broken ceiling at 2,800 feet agl, and overcast layer at 3,000 feet agl, a temperature of six degrees Celsius, a dew point of two degrees Celsius, and an altimeter setting of 29.70 inches of Mercury.

Wreckage and impact information

At the initial impact point there was an area of white paint transfer onto the concrete surface measuring about one foot wide and approximately 15 feet long. At the southwesterly end of this area, there were numerous very small pieces of pulverized red glass that appeared to be consistent with the material from the left wing navigation light lens. Approximately 17 feet passed the southwesterly end of the initial impact mark, there was another area of white and red paint transfer. This area measured approximately four feet by four feet, and contained small sections where the concrete surface itself had been chipped or gouged. At the northwesterly end of this impact area there were six well defined propeller strike marks/lines. The first four of these marks were 12 inches apart. The next one was separated by 15 inches, and the last was 21 inches from its predecessor. From that point to where the aircraft came to rest, there were a few very light paint transfer lines, and three small pieces of unidentified aluminum. The magnetic heading from the initial point of impact to where the aircraft came to rest was 015 degrees.

At the point where the aircraft impacted the blast fence, its engine had come in direct contact with one of the four-inch diameter steel support posts. The post itself had been displaced/bent about eight inches by the force of the impact. The forward portion of the fuselage, from the front of the engine compartment to a point just aft of the rear side windows, was consumed by fire. The right main gear leg was still attached within its gear strut attach box, but the left main gear leg had been torn loose from the fuselage structure. The left wing leading edge was crushed directly aft along its entire span, and the outboard two-thirds of the span was bent upward about 35 degrees. The most outboard one-third of the span had been ripped and torn away as far aft as the rear spar. The inboard two-thirds of the left wing retained most of its original airfoil shape, and although it suffered minor exterior fire damage, it still contained approximately 15 to 20 gallons of fuel. The right wing, which had come to rest on top of a chain link fence located just aft of an opening in the blast fence, had been totally consumed by fire, except for its associated steel components. Flight control continuity was established to all flight controls from the control yoke/rudders to each flight control bellcrank or attach fitting. Both the upper and lower flap activation cables were traced from their attach point on the manual flap handle to their attachment to the flap actuation pushrods. The manual flap handle support structure had melted in the fire, but the handle itself was found in the handle full-up/ flaps full-down position (flap handle latch positioned in the upper notch of the flap handle ratchet plate). The horizontal stabilizer jack screw was measured at 7.6 inches, which was later determined to be one-third of the distance forward of the travel between takeoff and full nose up.

After the aircraft was moved to the facilities of AvTech Services, LLC., in Maple Valley, Washington, both the airframe and engine underwent further examination. During that examination there were no non-impact induced anomalies found in the aircraft's primary structure or engine, nor were there any apparent anomalies in the aileron, rudder or horizontal stabilizer systems.

Because the flap actuation mechanism had been found in the flaps full-down position, the manual flap handle assembly was also subjected to further examination. That examination revealed that eight out of the nine rivets that pass through the handle at different locations still remained in part or in whole. Some of the rivets remained in there entirety, including the one upon which the handle latch assembly return spring rests, while the shafts of others had melted away, and only their heads and/or bucked ends remained. All eight had suffered extensive heat damage, and all eight had deposited varying amounts of aluminum slag residue near the edge of the holes that they passed through. The ninth rivet, which originally passed through the flap latch pivot inner bushing was not present. In addition, the two washers and the pivot inner bushing itself, which are normally held in place by the ninth rivet, were missing. The outer pivot busing, which pivots aro