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Approach Power Compensator (APC) - update for current version, added section from NATOPS concerning APC usage.
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(Approach Power Compensator (APC) - update for current version, added section from NATOPS concerning APC usage.) |
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=== Approach Power Compensator (APC) === | === Approach Power Compensator (APC) === | ||
* The '''APC''' is a closed loop system that automatically regulates | * The '''APC''' is a closed loop system that automatically regulates engine thrust to maintain on-speed (orange donut in the AoA indexer) for carrier recoveries and FCLP. | ||
* Type {{Key press|Ctrl|s}} to toggle the '''APC on/off'''. APC is also disengaged by setting the throttles to MIL, (98 percent rpm) or idle, (68 percent rpm) or raising the landing gear handle or when weight on the wheels. | * Type {{Key press|Ctrl|s}} to toggle the '''APC on/off'''. APC is also disengaged by setting the throttles to MIL, (98 percent rpm) or idle, (68 percent rpm) or raising the landing gear handle or when weight on the wheels. | ||
* When disengaged the '''AUTO THROT''' caution light, (on the left side of the HUD) illuminates for 10 seconds. | * When disengaged the '''AUTO THROT''' caution light, (on the left side of the HUD) illuminates for 10 seconds. | ||
==== (NATOPS 8.5.3) guidelines for APC use ==== | |||
Practice is required to develop the proper control habits necessary to use APC. For the APC to perform satisfactorily, smooth attitude control is essential. Large, abrupt attitude changes result in excessive power changes. APC use is not recommended in gusty conditions. The APC will overcontrol AOA fluctuations resulting in large airspeed and/or glideslope deviations. | |||
As the initial turn from the 180 position is made, the aircraft will momentarily indicate up to 2 units slow. The APC will adjust power to correct back to on-speed condition throughout the remainder of the turn. Upon rollout on glideslope, the pilot must override the tendency for the nose to pitch up by maintaining slight forward stick. The aircraft will indicate 1 to 2 units fast, which will slow to on-speed within 5 seconds. | |||
The use of DLC in conjunction with small attitude changes to maintain glideslope will minimize AOA deviations and result in optimal APC performance. Timely use of DLC can also be used to more rapidly correct from a fast or slow condition. | |||
Close-in corrections are very critical. If a high, in-close situation develops, the recommended procedure is to stop the meatball motion and not try to recenter it. A low, in-close condition is difficult to correct with APC and often results in an over-the-top bolter. It may be necessary to disengage or manually override APC in order to safely recover from a low in-close situation. Throughout the approach, the pilot should keep his hand on the throttles in the event APC disengages inadvertently. A smooth throttle transition from AUTO to BOOST mode can be achieved by depressing the CAGE button on the outboard throttle grip. | |||
Notes | |||
* Approaches that result in steep bank angles (greater than 30!) and/or short groove lengths should be avoided be- cause of the large thrust reductions required and the short periods of time available to make proper corrections. | |||
* Disengagement of APC by any means other than the throttle MODE switch, will result in illumination of the AUTO THROT light for 10 seconds. | |||
[[File:F14 approaching Nimitz.jpg|270px|thumb|Approaching Nimitz carrier: flaps set, hook lowered]] | [[File:F14 approaching Nimitz.jpg|270px|thumb|Approaching Nimitz carrier: flaps set, hook lowered]] | ||