The aircraft landing at excessive vertical descent rate or the landing on a surface other than the prepared runway, with one or more landing gear that is combined with a specific aircraft landing weight is considered as a hard landing. The flight crew usually reports the hard landing occurrence that will initiate the maintenance procedure of the aircraft. A visual inspection is used to insure that the aircraft is serviceable after a hard/overweight landing. The detailed inspection of the landing gears, aircraft structure and all essential systems is a very costly and cumbersome maintenance. The Hard Landing Indication System (HLIS) is used to make a quantitative assessment of defined high load event. The HLIS records significant aircraft parameters throughout the flight duration and reports on request one value derived from these parameters. That value, referred as G readout, along with aircraft estimated weight at landing, allow an evaluation of a reported Hard Landing event. The system is consulted following a flight crew report of a Hard Landing event to determine the need for more detailed inspections thus helping to reduce unnecessary aircraft inspections and landing gear quarantines. The system accelerates initial disposition of the aircraft following a Hard Landing event. In order to certify the HLIS, a careful safety assessment was performed to determine the system compliance to the regulations. The HLIS critical functional failure modes are classified in two categories; valid but significantly erroneous G indication and loss of system. The valid but significantly erroneous G indication may lead to the incorrect maintenance disposition and expose an aircraft to the risk of continued flight with structure that has seen loads exceeding its design values. The failure mode of importance in this case is that the actual G data is significantly higher than the displayed G readout data. This failure condition is considered Hazardous to safety because the structure may develop cracks that could progress undetected to failure. The analysis of the Hard Landing Indication System was completed with the help of a Failure Modes and Effects Analysis (FMEA). The failure modes associated with each component were noted and the effects of the failures on the system and on the aircraft were stated. The multiple failure scenarios were analyzed using the Fault Tree Analysis (FTA) technique.
Hard landing indication system
2009
8 Seiten, 4 Bilder, 7 Quellen
Conference paper
English
British Library Conference Proceedings | 2010
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