Boeing 777 Aircraft Fault Isolation Manual
Books.google.co.th - Proceedings of the First Symposium on Aviation Maintenance and Management collects selected papers from the conference of ISAMM 2013 in China held in Xi’an on November 25-28, 2013. The book presents state-of-the-art studies on the aviation maintenance, test, fault diagnosis, and prognosis for the aircraft.
Proceedings of the First Symposium on Aviation Maintenance and Management-Volume II.
Each system must detect fault conditions to prevent the system from using failed components. Systems contain monitors sufficient to detect faults as necessary to meet safety requirements and other economic objectives. Figure 13 illustrates the fault detection and processing concept used on the Boeing 777. When a member system detects a fault, it: 1. Reports to the flight crew display system that the condition should be annunciated (if necessary) to the level necessary to identify the specific required flight crew awareness/actions, and/or aircraft dispatch limitations. This indication is known as a flight deck effect (FDE).
Flight deck effects are normally displayed as a part of the basic flight crew display system. They provide information at the level that will best support flight crew determination of their response to this condition. In general, this means that a function is lost or degraded. For example, a pilot need not know which component caused a function to be lost, as his actions only change based on which function has been lost.
Reports this fault to the CMCS (to the level necessary to indicate to the mechanic what needs to be done to correct the fault—sometimes this may require additional monitors to provide better isolation than those used to identify that a fault has occurred). This indication is known as a fault report. Airplane maintenance manual and supporting data Figure 13. Boeing 777 CMCS fault detection and processing concept. The flight crew display system reports to the CMCS that the flight deck effect is being displayed. Based one or more received fault report(s), the CMCS generates a message for the maintenance crew, and correlates it with the flight deck effect. This message is known as a maintenance message.
Boeing 777 Manual
The maintenance message contains an identification number, which points to a procedure in fault isolation manuals, and text to indicate what has been detected, and, optionally, the LRUs that could contain the fault. In a federated BITE system (where there is no CMCS consolidation function, e. G., where BITE data is displayed on LRU front panels), there is effectively a one-to-one relationship between the fault reports and maintenance messages; that is, an LRU will record a fault report when a fault is detected, and display the associated maintenance message when requested by the operator. On aircraft with a CMCS, fault reports are transmitted by systems to the CMCS. Although in many cases there is a one-to-one relationship between fault reports and maintenance messages, the CMCS may consolidate multiple fault reports (usually from multiple LRUs) to produce a single maintenance message.
Boeing 777 Systems Manual
The CMCS stores maintenance messages in fault history memory for later interrogation. As ground maintenance often results in temporary display of maintenance messages, messages are normally not stored when the aircraft is on the ground. The CMCS displays maintenance messages and correlated flight deck effects to the operator or reports them to ground stations via air to ground data links. Figure 14 shows a typical CMCS single maintenance message display for the Boeing 777. Figure 15 shows a flow diagram of the steps that an airline might follow during turnaround of an aircraft. When the aircraft first arrives at the gate, the mechanic checks for any flight deck effects or log book entries. If there are none, the aircraft can be returned to service.
Boeing 777 Aircraft Fault Isolation Manual Images
If there are flight deck effects or logbook entries, the mechanic will normally check the minimum equipment list and defer repair of the condition if allowed. If deferral is not allowed or desired, the mechanic will fault isolate using the CMC and the fault isolation manual (FIM), make the repair, confirm the repair, and then return the aircraft to service. The time is very limited in this condition, so the mechanic may choose to quickly replace multiple LRUs in an attempt to allow the aircraft to leave with minimal delay.
This causes removal of some nonfaulty equipment, but may be in the best economic interest of the airline (as the costs of delay or cancellation can be large). Member System Fault Reporting. The member systems contain monitors that detect fault conditions. Most of these monitors have been incorporated to detect faults that threaten the integrity of the system. Others are incorporated to detect economic fault conditions (e. G., a fault causing increased use of fuel by the engine), or to provide improved fault isolation for maintenance. A wide variety of monitors are used in the various systems on the aircraft.