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flyingscampi

Gatwick Noise Abatement

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Gatwick plates say the following about Noise Abatement:“Cross Noise Monitoring Points not below 1202' QNH (1000' QFE) thereafter maintain minimum climb gradient of 4% to 3000' to comply with Noise Abatement requirements.”When configuring the FMC, does this mean I should:Option 1Set REDUCTION height to 1000AGL and ACCEL height to 1000AGLOption 2Set REDUCTION height to 1000AGL and ACCEL height to 3000AGLOption 3Something else….If Option 1 is correct, should I restrict the speed by using SPD INTV with VNAV or setting the MCP speed with LVL CHG? This is to make sure I climb more quickly to 3000 instead of accelerating to the cleared speed (eg 250 below 10,000ft).Any input from a real pilot that has flown out of EGKK gratefully received :)

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The departures have lat/long for the noise points. You can drop them into your FMC as a custom waypoint and give them a crossing restriction. The charts that i have shows a minimum cross height of 1210ft. That climb gradient is about 243ft per mile. You can set your reduction where ever you want as long as you can make atleast 243 per mile to 3000. So you can either stay configured and fly your all engine V2 speed to 3000 or takeoff and clean up on schedule as long as you can maintain 243 per mile through out the process. So if your all engine V2 ground speed was 180, you would need roughly 720 feet per minute up to 3000ft. That's a low gradient. Very easy to meet that restriction and clean up as long as you keep 243 per mile. So a good wag is 4% times your ground speed for a feet per minute or use the ground speed chart at the bottom of the departure plate. Even if you cleaned up and accelerated to 250, as long as you keep more than 1100ft per minute you are good. If i lost an engine in the process, my noise would be 50% lower but in that case I could care less about the noise.

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The departures have lat/long for the noise points. You can drop them into your FMC as a custom waypoint and give them a crossing restriction. The charts that i have shows a minimum cross height of 1210ft. That climb gradient is about 243ft per mile. You can set your reduction where ever you want as long as you can make atleast 243 per mile to 3000. So you can either stay configured and fly your all engine V2 speed to 3000 or takeoff and clean up on schedule as long as you can maintain 243 per mile through out the process. So if your all engine V2 ground speed was 180, you would need roughly 720 feet per minute up to 3000ft. That's a low gradient. Very easy to meet that restriction and clean up as long as you keep 243 per mile. So a good wag is 4% times your ground speed for a feet per minute or use the ground speed chart at the bottom of the departure plate. Even if you cleaned up and accelerated to 250, as long as you keep more than 1100ft per minute you are good. If i lost an engine in the process, my noise would be 50% lower but in that case I could care less about the noise.
Thanks for that comprehensive answer Rick, much appreciated :)Time for some practice...

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