IAD98LA114

NTSB accident investigation · Let Blanik L-13 · Hammonton, NJ · July 11, 1998

Accident · No injuriesLimited investigationFinal report
Date
July 11, 1998, 16:30 local (20:30 UTC)
Place
Hammonton, NJ
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N49CCLet Blanik L-13
Weather
Visual (VMC) · Day
Status
Completed · report February 16, 2001
Report
Approved by Office Director
FAA report
19980711036199A
Case key
45303

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

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

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Gear collapsedLanding - flare/touchdown
Landing gear,main gear attachment - collapsed
Maintenance,pressurizing - improperCause

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 narrative

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."

Aircraft

Registration
N49CC
Reported as
Let Blanik L-13 (BLANIK L-1)
Category
Glider
Serial number
175226
Airframe hours
837
Engine
unknown
Damage
Substantial damage
Flight
Personal · Part 91
Registered owner
South Jersey Soaring Society
Airworthiness certificate
Standard, Normal
Last inspection
Annual · April 3, 1998 · 10 hours before
Departed
N81
Airport
N81 · Hammonton Airport, runway 3, 3,600 × 50 ft, asphalt

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
58
Certificate
Private
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 3, Valid Medical--w/ waivers/lim
Seat
Rear
Flight hours
1,360 total · 13 in this make and model · 1,225 as pilot in command · 9 in the last 90 days · 6 in the last 30 days · 2 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
280° at 12 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
81 °F, dew point 52 °F
Altimeter
29.00 inHg
Observed at
ACY, 15 nm away

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.