Rpredict's Reliability Case studies

• In this section an overview is given of some most interesting Reliability Case studies.

 

Reliability prediction analysis for the fluids and combustion facility fuel-oxidizer management assembly and combustion chamber SYNOPSIS The National Aeronautics and Space Administration (NASA) is developing a modular, multiuser experimentation facility for conducting fluid physics and combustion science experiments in the microgravity environment of the International Space Station (ISS). This facility, called the Fluids and Combustion Facility (FCF), consists of three test platforms: the Fluids Integrated Rack (FIR), the Combustion Integrated Rack (CIR), and the Shared Accommodations Rack (SAR). This document is intended to provide an estimate of the Reliability of the Fuel-Oxidizer Management Assembly (FOMA) and Combustion Chamber contained in the Combustion Integrated Rack (CIR). Source: http://fcf.grc.nasa.gov/pdr/docs2/CIR-RPT-0063.pdf

Loss of normal brake system with the Iberworld Airlines Airbus A320-214, registration EC-GZD, at Groningen Airport Eelde on 12 March 1999 SYNOPSIS During taxi prior to departure the aircraft did not respond to the flightcrew's pedal brake application and in order to avoid a collision with another aircraft the captain manoeuvred the aircraft from the apron. The aircraft came to a stop in the grass adjacent to the apron. Investigation revealed that the origin of the failure was a disfunctioning braking and steering control unit. The Dutch Transport Safety Board is an independent governmental organization established by law to investigate and determine the cause or probable cause of accidents and incidents that occurred in the transportation sectors pertaining to shipping, civil aviation, rail transport and road transport as well as underground logistic systems. The sole purpose of such investigation is to prevent accidents and incidents and if the Board finds it appropriate, to make safety recommendations. Source: http://www.rvtv.nl/data/201201_2.pdf (2nd part English) The investigation was performed by the Dutch Transport Safety Board in close co-operation with the French Bureau Enquetes-Accidents and the Spanish Accident Investigation Committee. The combined efforts of the aircraft manufacturer, Airbus Industrie, the manufacturer of the braking and steering control unit, Messier-Bugatti, and the operator, Iberworld, were crucial with respect to the results of the investigation. History of the Flight On 12 March 1999 at 14:25 the Iberworld Airlines, S.A. Airbus A320-214 with registration EC-GZD received start up clearance for runway 05 for a domestic (intermediate) flight from Groningen Airport Eelde to Enschede Airport Twenthe (Twenthe Airbase) as IWD flight 7571. The final destination was Tenerife Airport (Reina Sofia). There were two flight crewmembers in the cockpit. The captain was pilot flying (PF) from the left seat, the first officer was pilot non flying (PNF) from the right seat. The aircraft was parked on the apron. At 14:29 IWD 7571 started to taxi to the holding point of runway 19, which is at the end of the apron. At the holding point of runway 19 the PH-SDN, a general aviation aircraft, was holding and waiting for its airway clearance. After departure of the PH-SDN, IWD 7571 was expected to taxi via runway 19 to the holding point of runway 05. At 14:30 both PF and PNF noticed that the aircraft did not respond to the PF's brake pedal input. On the cockpit voice recorder (CVR) it was recorded that the PF stated "We are without brakes" [In Spanish]. The PF stated that he made a quick anti-skid and nose wheel steering selection OFF and ON again, which should have reset the braking and steering control unit (BSCU), but without result. There were no warning messages of a possible brake failure presented in the cockpit. In order to prevent a collision with the waiting PH-SDN the PF manoeuvred IWD 7571 from the apron into the grass and applied reverse power with the intention to decelerate. The recorded elapsed time for these actions from the moment of the first pedal brake application was approximately 25 seconds. The left nose landing gear wheel and the left two main landing gear wheels got into the grass, adjacent to the apron. The left main landing gear wheels sank into the soft soil and the aircraft came to a stop. The left engine ingested some soil during the thrust reverse application and the bottom of the engine cowling came in contact with the ground. See photograph and situational schetch in appendix A and B. The passengers and the crew disembarked using (external) stairs. During the following days an Airbus Industrie field repair team inspected and repaired the EC-GZD at Groningen Airport. The EC-GZD departed on 16 March 1999 for a ferry flight to Tenerife for further repair and maintenance. Flight data recorder (FDR) data indicated that the anti-skid was ON and that the hydraulic system pressure was normal (3000 psi). Before taxi there was no pedal brake application. During taxi brake pedal input was applied, but without corresponding build up of the brake pressure system. The highest brake pressure recorded during pedal brake application was 64 psi. (Normal operating brake pressure is around 1000 psi) During start up and taxi the WHEEL page and the FLIGHT CONTROL page of the electronic centralized aircraft monitor (ECAM) display were selected. There were no master warnings recorded on the FDR. Flight crew conversations recorded on the CVR indicated that at two other moments before the incident the captain made a remark about the brakes. The first time was during the preceding flight, approximately three minutes after touch down at Groningen Airport, at 13:46 the captain stated "Look at the brakes how they got…" [In Spanish]. The second was during start up of the incident flight while checking the ECAM status, at 14:28 he stated "The bad luck of the brakes" [In Spanish]. The captain indicated in a post incident interview that his statements referred to the brake temperatures presented on the WHEEL page, which were higher than normal, but below the maximum allowable 300 degrees Celsius. During the previous flight from Tenerife Airport no other related irregularities were reported.