Two sensors are on the top of the aft lock link.

When the chapter/system element number is followed with zeros in the section/subsystem and subject/unit element number (28-00-00), the information is applicable to the entire system.

There are two types of numbering methods that may be used. For airplanes having an array of complex systems, the full System/chapter method of indexing is recommended. For small or relatively noncomplex airplanes, an abbreviated indexing method may be used.

When index numbering the maintenance manual, manufacturers may omit System/Chapters that are not applicable to the product or combine system/Chapters where it is feasible .

In aircraft maintenance, servicing refers to that servicing required on units as the result of the accomplishment of any other maintenance practice. It includes items such as the inflation or refilling of shock struts, the lubrication of control systems, the sterilizing of potable water systems, etc.

Phase letter "V" shall be used as a suffix on the cable identification code to identify the ungrounded wire or cable that is in a single-phase system.

A wire code consists of a circuit function code, wire number, wire segment letter and wire size.Frequently a suffix indicating ground ( N ) , phase (A, B, etc.) or thermocouple material(alumel, etc. ) is added.

In Wiring Diagram Manual, an alphabetical index by subject is to be included in the Introduction, as an assistance in locating the desired circuit.The index should show the chapter and subchapter in which a circuit of the system appears.

Revisions to a drawing are necessitated by changes in dimensions, design, or materials. When drawings contain such corrections, attention is directed to the changes by lettering or numbering them and listing those changes against the symbol in a revision block.

On B757 the external power of electrical system is checked by BPCU before supplied to its electrical network. If the EXT PWR is checked normal, the contactor is closed.

Many return oil filters have bypass valves inside. When the filter element is clogged the bypass valve opens, which makes the oil flow through the bypass