Timing of engine anti-ice after engine start
 

I'm looking to clarify the reasoning behind the timing of when to select the engine anti-ice on during the start sequence on Boeing aircraft. The FCOM states that the engine anti-ice should be selected on "after both engines have been started." Is there any reason to not select the engine anti-ice on after each engine is started as opposed to waiting for both engines? RB211 engines in particular.

Our Part B said to do exactly that - if the second engine start has problems the first engine started could be unprotected for some time. The after start scan flow checks and ensures that anti ice is selected correctly but the Part B 2a adverse weather says to select it immediately after any engine start needed.

hth

Make a judgement call on it based on how severe you perceive the icing conditions are. In most situations that you’d be prepared to take off in a couple of minutes of idle thrust without anti ice probably isn’t a big deal. However if there’s a prolonged delay before starting the second engine…

As others have said, make a sensible decision given what you’re doing and the environment. The other day we had to do a cross-bleed start and needed to be towed out of the ramp after starting one engine on stand in what I would definitely call icing conditions - a no-brainer to put the anti-ice on straight away.

So, make it easy. First engine started, anti ice on. Second engine started do the same. No thinking required.

Heaven forbid we should give any thought to what we’re doing.

Solution in search of a (non existent) problem?