Applepie81 From United Kingdom, joined Nov 2003, 68 posts, RR: 0 Posted (10 years 11 months 3 weeks 2 days 18 hours ago) and read 1296 times:
When an aircraft has been parked up overnight in icy conditions and has to fly the 'red eye' plus the airport has a short runway and requires full thrust take offs. Does the aircraft need time for the engines to warm up? it can't be too good or a plane to start up cold, taxi 2 minutes to the runway and do a full thrust take off.
Air2gxs From , joined Dec 1969, posts, RR:
Reply 2, posted (10 years 11 months 3 weeks 2 days 18 hours ago) and read 1252 times:
A common mistake is to treat jet engine like recips. True, on a recip you must wait for the engine to heat up to get peak efficiency. No so on a jet. You need to wait for the oil to heat up a little, but typically that happens fast.
This from the B767 AMM for the CF6:
The engine has a minimum starting temperature of -40 F (-40 C) for Type 2 oils. All engines are provided Type 2 oils. To acquire a lower start rating, a Type 1 oil is required. GE Service Bulletin 79-001 lists all approved lubrications and has the procedure for the Type 1 Service Evaluation. Type 1 oil is approved for use down to -65 F (-54 C).
As you can see you can start at an extremely low temp.
On the jumbo we normally wait for the oil to reach green band. That normally occurs on the first engine started before the fourth is started. And the fourth engine reaches green band before we complete our "before taxi checklist".