Night ILS Approach Ends in Powerline Strike Due to Glide Slope Failure

Casualties unknown • Dallas, TX, US

A pilot flying a night instrument landing system approach struck a powerline two miles short of the runway after relying on an inoperative glide slope receiver, leading to a fatal crash.

What happened

During a nighttime instrument landing system (ILS) approach, the aircraft collided with a powerline approximately two miles short of the runway. The incident occurred after the pilot received a low altitude alert from air traffic control. At the time of the collision, the left engine had already lost power and was feathered. Concerned about potential damage to the landing gear if retracted, the pilot chose to leave it extended.

The pilot reported that ice was accumulating on the windshield during the descent but stated he maintained visual contact through the left quarter of the windshield. He indicated he was flying the approach with a glide slope indication showing one dot high when he leveled off at an altitude of approximately 800 feet mean sea level (MSL). Shortly before impact, the pilot responded to an air traffic control query by stating he had contacted the ground, could see the runway, had ice on his windshield, and that his glide slope was not working.

The investigation

Post-accident examination of the aircraft's navigation equipment revealed that the glide slope receiver was inoperative, yet it continued to display a one dot high indication. This discrepancy likely contributed to the pilot's misjudgment of vertical position during the final approach segment. Additionally, checks of the altimeters showed only a 70-foot difference between them, indicating they were functioning correctly relative to each other.

Findings

The crash site elevation was recorded at 596 feet MSL. The combination of an inoperative glide slope receiver providing erroneous vertical guidance and the pilot's reliance on that data led to the premature descent into the powerline. The inability to maintain altitude after striking the obstruction resulted in the fatal outcome.

Safety message

Pilots must remain vigilant for discrepancies between instrument indications and actual aircraft attitude, especially during night operations in icing conditions. Verification of navigation system status is critical when visual references are limited or compromised by weather phenomena such as windshield ice.

Probable cause

The pilot's failure to maintain terrain clearance during a night ILS approach due to reliance on an inoperative glide slope receiver that provided erroneous vertical guidance, which resulted in the aircraft striking a powerline.

Frequently asked questions

What happened in the 1982-02-26 Beech D18S accident near Dallas, TX?

A pilot flying a night instrument landing system approach struck a powerline two miles short of the runway after relying on an inoperative glide slope receiver, leading to a fatal crash.

What aircraft was involved and where did it happen?

The accident on 1982-02-26 involved a Beech D18S, registration N8517Z, operated by Jim Billingsley, at Dallas, TX.

What was the probable cause of the accident?

The pilot's failure to maintain terrain clearance during a night ILS approach due to reliance on an inoperative glide slope receiver that provided erroneous vertical guidance, which resulted in the aircraft striking a powerline.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20020917X02112. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

Loading the flight search…