We use the TASS (assumed temp) method on the NG which in most cases will result in TO D2 (22K) but full CLB is recommended, having said that if you are light and have a low initial speed limit or level off then CLB 2 will often be preferable e.g. CLN departures from 26L at LGW. On this departure it is very important not to overshoot the DET inbound radial on the first turn to the East and we recommend that speed is limited to 190 Knots for this turn, a light weight aircraft with full CLB will give a high ROC and with a stepped climb to not above 4000 is likely to increase the risk of a TCAS RA and a high body angle.
Apart from reduced engine wear both methods will reduce noise significantly. TASS must not be used on contaminated runway, or when wind shear is likely or with a pronounced temp inversion, typically +10c change in the first 1000 ft
To further save engine wear and noise we also normally use improved climb which results in a much longer take off run and higher v speeds but a higher TASS which lowers the engine temp (the engine EEC thinks its warmer out side than it is) your ground run is much longer so i tend not to use this at places where the bird strike risk is high e.g. FAO/AGP/AMS
Last edited by LNIDA; 9th Jul 2014 at 04:43.