Originally Posted by
Shatwa07
whats the difference between auto start and manual start , when the pilot uses manual start.
An Auto start will just do a normal robotic start: For IAE engines: Engine master ON: 30 seconds cranking and then one ignition comes alive and fuel will ignite ( unless ignition failure) regardless of the N1/N2 speed and EGT which can lead to start fault in some cases ( strong tailwind, very hot conditions.. etc)
Manual start you control the cranking time with the ENG man start p/b and control when to ignite the engines and send fuel ( With ENG Master sw to ON) and both igniters will be ON increasing your chance of a successful engine start.
For IAE engines, manual Start is recommended when:
**Tailwind greater than 10 kt.
** After aborting a start because of engine EGT over limit or low start air pressure or no N1 rotation or hung start.
** When expecting a start abort because of degraded bleed performance due to hot conditions or high altitude airports.
**Marginal performance or the external pneumatic power.
During manual start, the crew must pay attention to the starter limitations and since the FADEC has limited control, the crew must monitor the engine acceleration and be ready to abord the start if required as the FADEC has no authority to abort the start.