Aviation Accident Summaries

Aviation Accident Summary IAD98LA114

HAMMONTON, NJ, USA

Aircraft #1

N49CC

Let BLANIK L-13

Analysis

The glider pilot performed a landing to the runway. He described the landing as 'firm' and said he heard a 'bang' and scraping noises at touchdown and during rollout. Examination of the airframe revealed significant structural damage around the nose landing gear. The certificated airframe and powerplant mechanic who performed the repair work recorded his observations in a written statement. He said: 'The shock absorber was found to be full of fluid instead of half fluid and half 468 psi nitrogen. This resulted in the shock absorber being a rigid device. Because this device was improperly serviced sometime in the past, it transferred landing loads directly to the above named structures instead of dissipating them.'

Factual Information

On July 11, 1998, at 1630 eastern daylight time, a Blanik L-13 glider, N49CC, was substantially damaged during landing at the Hammonton Airport (N81), Hammonton, New Jersey. The certificated private pilot and passenger were not injured. Visual meteorological conditions prevailed for the local personal flight that originated at N81, at 1430. No flight plan had been filed for the flight conducted under 14 CFR Part 91. In a written statement, the pilot said: "This was a local soaring flight lasting just under two hours in good weather with a passenger...aboard. The aircraft was within CG limits and below gross weight. The landing that terminated this flight was a firm touchdown on or near the runway centerline in a light crosswind, with no significant aircraft side drift at the moment of touchdown...I heard a 'bang' at touchdown, followed by scraping noises as the aircraft came to a stop." Preliminary examination of the glider by Federal Aviation Administration (FAA) Aviation Safety Inspectors revealed only minor damage. Detailed examination of the glider during repairs revealed the glider had sustained substantial damage. The certificated airframe and powerplant mechanic who performed the repair work recorded his observations in a written statement. He said: "Substantial damage to the floor between frames #3 and #5 and associated structural support members was found. The lower skins between frames 1 & 3 and 3 & 5 were damaged along with the shock absorber mounting pins. The shock absorber was found to be full of fluid instead of half fluid and half 468 psi nitrogen. This resulted in the shock absorber being a rigid device. Because this device was improperly serviced sometime in the past, it transferred landing loads directly to the above named structures instead of dissipating them."

Probable Cause and Findings

Improper maintenance, which resulted in an over-pressurized landing gear.

 

Source: NTSB Aviation Accident Database

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