Operation of the Thrust Reverser System - Case Study Example

CREATING A PROCESS DESCRIPTION Process: Operation of the Thrust Reverser System Thrust reversals also known as reverse thrust, is the temporary divesion ot an aeroplanes engine’s exhaust so that the thrust produced is directed forward, this acta against the forward travel of the aeroplane thus deceleration.Thrust reversers are used by many jet aircrafts to help slow down just after touchdown, reducing wear on the brakes and enabling shortwet landing distances. Reverse thrust is typically applied immeadiately after touchdown, along often with spoilers, to improve deceleration early in the landing roll, when residual aerodynamic lift and high speed limit the effectiveness of the friction brakes located on the gear. When thrust is reversed there will be a sudden increase in engine noise (Asbury, Yetter, United States & Langley Research Center, 2000). According to the policies and procedures of SWA, the use of thrust reversers for all landings, regardless of the run-way length or condtions is clearly specified. At the time of the accident, SWA’s FAA-approved flight manual(FOM)stated, in, part, that after the plane touches down on the run-way: “ Initiate reverse thrust: Raise the reverse thrust levers to the reverse idle interlocks. After the interlocks release, modulate reverse thrust, as required. Avoid exceeding engine limits. Minimum reverse thrust is 65 percent N1(Engine Fan speed). When required, reverse thrust to enginelimits may be used. Initiating reverse thrust at touch downis an important factor in minimizing brake tempratures.” The SWA FOM also stated te following; (Manual) Brakes and thrust reversers should be applied together. Use thrust reversers as possible during landign roll. In addition, the SWA FOM stated the following; Both pilots will monitor systems for warnng flags, lights, and out of tolearnce conditons.The first officer will advice the captain of deviations from established policies, procedures, and/or regulations. Purpose A flying pilot is required to deploy the thrust reversers as soon as posible after nosewheel touchdown for all landings. SWA guidance especially emphasis immediate deployment of revers thrust when braking action is reported to be less than good. The monitoring pilot is also rquired to be attentive for procedural deviations during all landings. The use of Autobrakes, is during landings under some conditions. The use of Autobrakes when landing on short or slippery runways requires a change in the sequence of landing tasks for both the flying pilot and monitoring pilot. Stakeholders Federal Aviation Administartion(FAA) and South Western Ailines. Federal aviaion Admionistration granted operatinal license to Southwest Airlines to be in airline business. SWA guidelines categoricaly require that pilots deploy the thrust reversrs as soon as possible after nosewheel touchdown for all landings. The accident pilots reportedly aware of the stipulated guidelines about reverse thrust policies, still went ahead and never applied reverse thrust immeadiately after touchdown. The first officer stated that after , when he realized that the captain had not deployed thrust reversers, he moved the thrust levers to command reverse thrust. That according to FDR data, thrust reverse action was activated 15 seconds after touchdown. FDR data, further indicated that the thrust reversers were eventually fully deployed about 18 seconds after touchdown, anfd the pilots held maximum reverse thrust until the airplane came to a stop off the end of the runway. Moreover, the Safety Board’s review of FDR data from four SWA 737s that landed and came to a stop onn runway 231C at MDW during the 21 minutes before tha accident implied that the reverse thrusts on these airplanes was deployed promptly after landing. Thereby concludind that the pilots would have been able to stop tha airplane on the runway if they had commanded maximum reverse thrust promptly after tiouch down. The pilots stated, that as the landing roll continued, diassatisfaction with the airplanes deceleration, as recoreded by FDR data, about 12 seconds after touchdown, they transitioned from auto breaking to to maximum manual-wheel breaking. Responsibility. The Pilots. Both pilots should take responsibiliy for grossly failing to follow crucial guidelines that might have averted the accident. According to FDR data The flying pilot and his first officer perharps out of panic; only deployed reverse thrust 18 seconds after touchdown. Whereas, the requirements stipulate that the flying pilot immeadiately deploy thrust reversers after the nose wheel touches the ground.This is further reinforced by the fact that despite the captains claims in encountering difficulties initially, in his attempts to deploy the thrust reverseres, they to extended normaly in a coordinated manner for the first offocer. Besides, the VCR recorded no comments or utterances indicating that both pilots were experiencing trouble with the thrust reverseres. In addition post accident interviews with other SWA pilots indicated that most had not experienced any difficulty deploying the thrust reversers, niether had they heard of others doing so. Thus the Safety Board’s conclusion that the pilots delay in deploying thrust reversers cannot be attributed to physical or mechanical difficulties. SouthernWest Airlines(SWA). SWA should also take responsibility for rash implementation of new policy (Just a week before the accident). This policy would have required the use of autobrakes during landings under some conditions, including the accident landing conditions. Both pilots lacked previous operational experience with autobrakes in spite of completing the self-study trainning module provided to all pilots by SWA. Procedure Description/flow charts. A flow chart is a kind of diagram that represents a process or algorithm, showing the steps as various boxes of some kind and their order connecting them with arrows, It illustrates a solution to a given problem. For example the flow chart below tries to illustrate the manner of culpalbility that affects SWA as the owners of the Boeing 737 and employers of the pilots. Process Measure The circumstances of this accident demonstrated that their was a need for a method of quantifying the runway surface conditions, in a more meaningful way in order to support airplane landing calculations (Asbury, Yetter, United States & Langley Research Center, 2000). The practice by the safety board of analyzing an airplane’s actual landing performance in the aftemath of an accident, based on airplane recorded data; demonstrates that runway surface conditions, and breaking effectiveness information can always be extracted from an aeroplane’s recorded data. Reference Asbury, S. C., Yetter, J. A., United States., & Langley Research Center. (2000). Static performance of six innovative thrust reverser concepts for subsonic transport applications: Summary of the NASA Langley Innovative Thrust Reverser Test Program. Hampton, Va: NASA Langley Research Center. Read More