Wilgrove, NC, USA
N1453T
Piper PA-28-140
According to the pilot, the aircraft underwent an annual inspection on August 2, 2001. One of the tasks performed was the removal and replacement of the oil pump impellers, and the throttle linkage must be disconnected to expedite the job. Nine-tenths of a flight hour and seven takeoffs after returning the aircraft to service, the throttle would not respond to the pilot's input while in the landing pattern. The pilot executed a partial power go-around, and the aircraft crashed into trees at the end of the runway. Wreckage examination revealed the throttle cable disconnected at the carburetor, and no drilled bolt, castellated nut or locking cotter pin that forms the throttle cable-to-carburetor connection was found. The pilot mentioned that since the annual inspection, he detected a slight detent in the throttle motion at about 1,100 rpm engine speed, but failed to mention it to the mechanic. The FAA certified IA who signed off the work stated he was 99.9 per cent certain the attaching hardware was correctly installed.
On August 17, 2001, about 1300 eastern daylight time, a Piper PA-28-140, N1453T, registered to a private individual, operating as a Title 14 CFR Part 91 personal flight, crashed while performing a go-around at the Wilgrove Airpark, North Carolina. Visual meteorological conditions prevailed and no flight plan was filed. The aircraft received substantial damage, and the private-rated pilot, the sole occupant, was not injured. The flight departed the same airport about 30 minutes before the accident. According to the pilot, he departed runway 17 directly into the landing pattern for touch-and-go landings. As he approached short final for his first landing, he noticed he could not reduce power, and elected to perform a go-around. The throttle did not respond in the increase power direction as well, and he over flew the runway at 100 to 150 feet agl, 1,900 rpm, and 70 mph until he encountered trees at the departure end. Unable to sustain level flight, he reasoned his best alternative was to perform a full stall landing into the tree canopy. According to the FAA certified aircraft inspector who conducted an annual inspection on N1453T on August 2, 2001, one of the jobs to be performed was compliance with airworthiness directive No. AD 96-09-10, which requires the engine oil pump impellers to be replaced. The throttle linkage has to be disconnected when the crankcase is separated to perform the task. Although the inspector did not perform the impellers change himself, he inspected the finished job, and signed it off. He stated that he is "99.9 percent sure" that the castellated nut was properly replaced onto the threaded connector that forms the throttle linkage-to- carburetor connection, and that a new, properly sized cotter pin was installed to lock the castellated nut in place. According to an FAA inspector, the pilot is one-half owner of the aircraft, based at the Wilgrove Airport, just east of Charlotte. Since its purchase, on about July 1, 1999, the pilot has flown the aircraft about 40 hours. After the annual inspection, the pilot noticed that the aileron, elevator, and elevator trim controls moved more freely than he remembered, and attributed it to the mechanic's lubricating the controls during inspection. However, for his own peace of mind, the pilot had an instructor accompany him the next time he flew the aircraft, and the CFI confirmed that the "looser" feel was due to lubrication. The pilot also stated that he felt a slight detent in the throttle motion of travel at about the 1,100 rpm engine speed range, but did not inform the mechanic. The aircraft had operated about 9/10 hour, including seven takeoffs since being returned to service following the annual inspection on August 2, 2001. Post crash examination of the aircraft by the inspector revealed the throttle cable separated from its actuator arm at the carburetor, and the attaching hardware, namely, the drilled bolt, castellated nut and cotter pin, were missing. Efforts to find the attaching hardware at the crash site were futile. The throttle setting appeared to be at about the mid-range position. Actioning the throttle from the cockpit revealed normal control movement right down to the rod end that forms the attach point to the carburetor's actuator arm.
The failure of maintenance personal to properly reconnect the throttle-cable-to carburetor attachment, resulting in a throttle cable disconnection while in the landing pattern, and collision with trees. A factor in the accident was the failure of the pilot to obtain maintenance assistance once unfamiliar throttle action was detected.
Source: NTSB Aviation Accident Database
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