# NTSB IAD98LA114: Let Blanik L-13, N49CC, Hammonton, NJ, July 11, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 11, 1998, 16:30 local (20:30 UTC) - Place: Hammonton, NJ - Location: 39.6675° N, 74.7577° W: Placed by OpenAirDocs at HAMMONTON MUNI (N81), within about a mile (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=39.6675&lon=-74.7577&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report February 16, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 45303 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=IAD98LA114 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/45303/pdf - Page: https://openairdocs.org/ntsb/IAD98LA114 ## Probable cause Improper maintenance, which resulted in an over-pressurized landing gear. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Gear collapsed, landing - flare/touchdown - landing gear,main gear attachment - collapsed - maintenance,pressurizing - improper (cause) ## 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](https://openairdocs.org/deregistered/N49CC-2012-12-13), registration cancelled 2012-12-13, S/N 175226, built 1972 (OpenAirDocs) - Reported make and model: Let BLANIK L-13 (BLANIK L-1) - Registry model: [Let BLANIK L-13](https://openairdocs.org/model/let-blanik-l-13) (registry code 1360306) (OpenAirDocs) - Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs) - Category: Glider - Serial number: 175226 - Airframe hours: 837 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 58; 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 (OpenAirDocs). - [Accident 19980711036199A](https://openairdocs.org/incident/19980711036199A), Jul 11, 1998: Let L13BLANIK, Hammonton, NJ, Substantial damage. Investigation on-going to determine PIC of aircraft. (.19) on July 11, 1998, at 1630 eastern daylight time, a blanik L-13 glider, N49CC, was substantially… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.