TECHNICAL DICTIONARY                                  96

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MACH TRIM, Correction to airplane attitude (nose up)      馬赫配平，

during flight at high speed by using the horizontal         用水平安定面對高速飛行中的飛機的俯仰姿態所做的

stabilizer.                                               調整（機頭朝上）。

MAGNETIC HEADING, The heading of the airplane             磁航向，

relative to magnetic north.                                 相對于磁北的飛機航向。

MAGNETIC VARIATION (1), The difference between            磁差（1），

magnetic and true north.                                    真北與磁北的差別。

MAGNETIC VARIATION (2), The orientation of a              磁差（2），

horizontal magnetic compass with respect to true north.     相對于真北的水平磁羅盤定位。因為地面的磁力線在作

Because there is a continuous small change of direction   不斷的微量改變，磁偏角在長時間內多數是不一致的。每

of lines of magnetic force over the surface of the earth , 五年Jeppesen手冊會按照國際慣例校正等磁偏角線（等

magnetic variation at most locations is not constant over 磁差線）。（見基點偏差）

long periods of time. Lines of equal magnetic variation

(isogonics lines) are updated on Jeppesen charts every

five years in accord with worldwide practice. (see

Station Declination).

MAIN ENGINE CONTROL, A component on the engine            主發動機控制器，

for controlling fuel flow for starting and engine operation. 發動機上為發動機起動和運轉控制燃油流量的部件。

MAIN GEAR, The main wheels with the attachments for       主起落架，

supporting the airplane on the ground.                      用以在地面支撐飛機的主輪及其附件。

MAINTENANCE, Work accomplished in support of the          維修，

structure and systems of an aircraft. It includes,          在保障飛機系統和結構時所做的工作。包括檢查，大修，

inspection, overhaul, repair, preservation and the        修理，保養和部件更換。

replacement of parts.