Aviation Accident Summaries

Aviation Accident Summary LAX98LA244

WINNEMUCCA, NV, USA

Aircraft #1

N14692

Bellanca BL-17

Analysis

The airplane had been on a cross-country flight, which was terminating at the accident airport. The airplane had undergone an annual inspection 3 weeks prior to the accident with no discrepancies noted. After reaching the accident airport environment, the pilot retarded the throttle and noted the airspeed was 120 knots with a loss of manifold pressure. The engine continued to run, but was not producing power. The landing gear is self-activating, and when the airplane slows below 105 knots indicated and the throttle is less than half full, the landing gear will automatically extend. A safety mechanism is in place, so if the throttle is full forward and the airspeed drops below 105 knots, the gear will not extend. The pilot contacted the tower to inform them of her situation, and that she would be able to make the airport with no further problems. Simultaneously, the airspeed fell below 105 knots and the landing gear extended with the throttle in the full forward position. When the airspeed fell below 80 knots, the pilot knew she was not going to clear the railroad tracks and power lines. She made a shallow left turn to fly underneath the power lines and attempted a forced landing on a road. Examination of the airplane revealed that the throttle cable rod end had separated from the throttle body attach point disconnecting the linkage between the throttle and engine. It was noted that the cotter key and jam nut were missing from the assembly and were unable to be located. Further investigation revealed that the throttle cable assembly had been replaced 7 months prior to the accident. It was also noted that the assembly was not from the manufacturer, but is widely used in the industry. The manufacturer reported that they do not authorize any substitutions of their parts.

Factual Information

On July 26, 1998, at 1335 hours Pacific daylight time, a Bellanca BL-17, N14692, experienced a loss of manifold pressure during cruise and made a forced landing in an area of sand dunes near the Winnemucca, Nevada, airport. The airplane, operated under 14 CFR Part 91, sustained substantial damage. The private pilot received minor injuries. The non-pilot rated passenger/owner was not injured. Visual meteorological conditions existed for the personal flight and no flight plan was filed. The flight originated at Boise, Idaho, at 1330 on the day of the accident. The flight was scheduled to terminate at Winnemucca. In a telephone interview with a Safety Board investigator, the pilot stated that the airplane had gone through an annual inspection 3 weeks prior to the accident. No discrepancies were noted with the inspection. On the day of the accident the pilot received a standard weather briefing. She reported that the only item of note during her preflight inspection was that her seat belt was found jammed. The seatbelt was repaired and the airplane departed Boise with no further discrepancies. The pilot flew direct to Rome, Nevada, and encountered rain showers that were not reported in her weather briefing from Boise. She stated that she circumnavigated around the storms and then flew direct to Winnemucca. The pilot reported that she made a slow descent into Winnemucca. She stated that she retarded the throttle and her airspeed was approximately 120 knots. At this point, she noted a loss of manifold pressure. The pilot stated that the landing gear is self-activating. If the airplane is slowed below 105 knots indicated and the throttle is less than half full, the gear will automatically drop. She stated that if the throttle is full forward and the indicated airspeed is below 105 knots, the gear will not extend. Approximately 1/2 mile from the airport, the pilot contacted Winnemucca and apprised them of the loss of manifold pressure, and stated that she would be able to make the airport with no further problems. She chose to land on runway 14. At the approach end of runway 14 there are railroad tracks and power lines. The pilot reported that her airspeed fell below 105 knots and the landing gear dropped with the throttle full forward. She stated that her airspeed decreased to 80 knots, and she knew she was not going to be able to clear the railroad tracks and power lines. She made a slow, shallow turn to the left to fly underneath the power lines. She then attempted to make a forced landing on a road, but hit a ditch next to the road, bounced, and came to rest in the sand dunes. The main landing gear was sheared off when it struck the ditch. The time since the last annual inspection (June 2, 1998), approximately 12 hours, was derived from the pilot's logbook. Aircraft total time could not be established by airplane logbooks. Tachometer time was recorded as 2007.8; however, no airplane total time was recorded. A Federal Aviation Administration (FAA) inspector examined the airplane on-scene. His examination revealed that the throttle cable rod end had separated from the throttle body attach point disconnecting the linkage between the throttle and engine. He stated that the cotter key and jam nut were missing from the assembly. Upon further investigation, it was found that the throttle cable assembly had been replaced on December 23, 1997. The FAA inspector further reported that the original throttle cable rod end had been reinstalled with the new throttle cable assembly. Examination of Bellanca 17-31-ATC illustrated parts Catalog (appended to file) revealed that the original throttle cable rod end was not the rod end that was installed at the time of the accident. Bellanca further stated that they do not authorize "any deviation from our approved data." Airplane and pilot information was unavailable, the pilot and owner refused to submit required documents.

Probable Cause and Findings

Loss of engine power due to a missing cotter key and jam nut, the use of an improper nonapproved part by other maintenance personnel, and failure to safety the installation which subsequently lead to a throttle/carburetor linkage disconnect.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports