POWER PLANT (GENERAL) - Trouble shooting

1. General

A. Trouble shooting is the systematic process of identifying the faulty element in an otherwise functional system and determining the actions necessary to restore the system to an operational condition.

B. Trouble shooting begins with recognition and documentation of the problem. Precise documentation is essential to isolation of the fault with a minimum expenditure of time and effort.

C. 737-300 Power Plant Trouble Shooting includes lists of common trouble symptoms and related trouble shooting procedures. Trouble shooting procedures are in the form of charts which include trouble shooting steps and corrective actions in a recommended sequence based on probability of component failure and how easy it is to do the necessary checks.

D. Trouble shooting procedures are based on the assumptions that follow:

(1) Double failures do not exist.

(2) The faulty system was fully operational before the fault indication with all equipment installed correctly.

(3) All relevant circuit breakers were checked.

(4) All applicable airplane/engine operating procedures were accomplished.

(5) The airplane is on the ground, it has been shut down in accordance with normal operating procedures and all power is off.

(6) Fault was accurately described.

E. All warnings, cautions and operating limitations related with power plant maintenance and operation must be used during trouble shooting.

F. Generally, electrical wiring is considered to be satisfactory. The location of the wiring, its environment, exposure to possible damage and experienced failure rate will be factors in determining the need for electrical circuit checks.

G. All electrical wiring and connectors must be correctly examined and installed with the standard practices (AMM 70-70-01/201).

2. Trouble Shooting Arrangement

A. Power Plant trouble shooting is separated into the major sections that follow:

Starting and Idle                                        AMM 71-00-41/101

Power and Engine Response                   AMM 71-00-42/101

Surge (Stall)                                                AMM 71-00-43/101

Oil System                                                   AMM 71-00-44/101

Fuel System                                               AMM 71-00-46/101

Misc Observed Problems
(Vibration, FOD, etc.)                               AMM 71-00-47/101

Engine Controls                                        AMM 71-00-49/101

Thrust Reverser                                       AMM 71-00-50/101

Fuel Indicating                                         AMM 71-00-53/101

Engine Indicating                                    AMM 71-00-54/101

Oil Indicating                                            AMM 71-00-55/101

Visual Checks                                           AMM 71-00-58/101

Engine Checks                                          AMM 71-00-59/101

B. Each section includes a listing of trouble symptoms related with the section. Each listed symptom includes a reference to the trouble shooting chart (figure) and block sn the chart to start trouble shooting for the particular problem.

C. Trouble shooting charts are given for major symptoms. Each chart is given a figure number. Component location illustrations and schematic diagrams are given where necessary to support trouble shooting.

(1) Prerequisites are given to make sure that the system is in the necessary mode, and include the power necessary and identification of the circuit breakers which need to be closed ("in"), to do the procedure. Time consuming operations such as engine operation are noted.

Circuit breaker locations are defined as follows.

EXAMPLE:                            6-3-B13
                                   P6-3 Panel, Grid Location B13

D. Visual checks (AMM 71-00-58/101) and Engine checks (AMM 71-00-59/101) sections given details for checks that show repeatedly in trouble shooting charts or that have a degree of complexity requiring a detailed procedure or specific illustrations. Visual checks are those checks which are done by visual observation only (opening of fan cowls or fan duct cowl and thrust reverser halves for access may be necessary). Engine checks are more complex and may require test equipment, engine operation, or removal of components.

E. Trouble shooting tips may be included in the section introduction to describe typical problems to the mechanic or technician, and to alert of specific pitfalls that can occur. F. Tests are given in section AMM 71-00-00/501 that may be referred to by the trouble-shooting charts, or as is necessary to follow maintenance activity. Test No. 12 in section AMM 71-00-00/501 is intended to be used as a diagnostic aid. Test No. 12 includes an engine run data sheet for use to record engine parameters to determine any necessary adjustments or component replacement. The engine data for the Idle Speed, Acceleration, Part Power, and MPA tests in Test No. 12 can be collected in one continuous engine run before analysis. Or, the analysis and related corrective actions can be done after each power level check.