ballyboley
28th Jun 2010, 07:35
As 737 questions seems to be the order of the day, here are a few more. I had originally hijacked an existing 737 questions thread but decided to put them here instead as this is about the NG not the classic.
And yes, I know the answers to these are probably contained within the manuals but its good to get some debate on the issues as well as the facts...
1. My operator has 22 and 24k derates on CFM56, while using 22k we get a CLB1 or CLB2 derate climb thrust, but not on 24k even with ATRT - it just sticks with CLB. Is there a reason why it doesn't use reduced climb thrust for anything other than a 22k derate? I can understand it missing on full thrust but thought both derates would use it or maybe its an operator specific thing?
2. Does anyone know of a simplified or excel based tool for working out brake cooling schedules? We have a very short turnaround but it would be useful to have a worst case at say 20oC for 145kts for each autobrake setting to save the need to check the schedule each time to see if reverse thrust can be avoided (especially on short sectors with very little cruise time to do this)
3. Due to short sectors we are often at a lower level than optimum. This causes great debate as many hold the standard view that its always worth climbing higher even for a 30 second cruise then descent, however there is a paragraph in the FCTM that mentions its not worth doing for less than 20mins cruise. The FMC will often show a small but still existent saving- I assume it takes everything into account including the cruise length? I know that its important to tell the FMC the actual winds at the step climb cruise level to get a more accurate saving as a stronger headwind would easily wipe out a small saving, but apart from that I wanted to double check the FMC is always right and therefore its always worth a climb.
Thanks as always.
And yes, I know the answers to these are probably contained within the manuals but its good to get some debate on the issues as well as the facts...
1. My operator has 22 and 24k derates on CFM56, while using 22k we get a CLB1 or CLB2 derate climb thrust, but not on 24k even with ATRT - it just sticks with CLB. Is there a reason why it doesn't use reduced climb thrust for anything other than a 22k derate? I can understand it missing on full thrust but thought both derates would use it or maybe its an operator specific thing?
2. Does anyone know of a simplified or excel based tool for working out brake cooling schedules? We have a very short turnaround but it would be useful to have a worst case at say 20oC for 145kts for each autobrake setting to save the need to check the schedule each time to see if reverse thrust can be avoided (especially on short sectors with very little cruise time to do this)
3. Due to short sectors we are often at a lower level than optimum. This causes great debate as many hold the standard view that its always worth climbing higher even for a 30 second cruise then descent, however there is a paragraph in the FCTM that mentions its not worth doing for less than 20mins cruise. The FMC will often show a small but still existent saving- I assume it takes everything into account including the cruise length? I know that its important to tell the FMC the actual winds at the step climb cruise level to get a more accurate saving as a stronger headwind would easily wipe out a small saving, but apart from that I wanted to double check the FMC is always right and therefore its always worth a climb.
Thanks as always.