ATPL Flight Planning Qn

[captainowie]

I am currently attempting to self-study ATPL Flight Planning, and I have come across what appears to be an inconsistancy between the two books I am working out of.

When planning an interrupted climb, eg from FL220-FL350, one set of notes tells of a "clayton's BRW", whereby the amount of fuel that would have been used to climb to (in this case) FL220 is added to the current Gross Weight to provide a fictitious BRW to use as the enrty argument for the climb tables. The climb data for the initial level is then subtracted from the climb data for the intened cruise level. However, neither the other book that I'm using nor the B727 P&OH mention anything of the sort. I'm getting a little confused :confused:

Can anybody out there please shed some light on the problem? The "clayton's BRW" method makes sense, but if nobody else uses it, I'd be better off ignoring it.

Thanks in advance
Cheers, Captainowie.

[Aussiebert]

the climb tables are bases on a start zone weight at sea level, so any data you pull out of those tables should be based on that...

for a climb from FL220 to FL350 (i'm assuming you have a weight at FL220), have a guess as to your start weight. you can do this by looking at the fuel burn to FL220 at about 2 tons lighter than you current weight(depending on your current weight). Tha basic idea is to be able to etimate what you BRW would be if you wanted to climb to be at FL220 at the weight you have for the scenario.

Sorry if thats confusing...

anyhow, using your estimated BRW (which only need to be to the nearest ton so you should be able to guesstimate right first time), extract the figuers for FL220, subtract them from the FL350 figures and theres your climb info for that segment. Its good if you have time (which in the exam, you may not) to check your estimate against actual info based on your figures.


hope that helps

[Tinstaafl]

It's been 12 or 13 years since I did SCPL/ATPL flight planning so take what I say with a large grain... :o


I **think** I recall that we started with current weight at the FL, worked backwards on the climb chart to derive what the BRW would have been had we just climbed to the current level, then used that BRW for a S.L. to the new, higher level climb.

There may have been an estimate in there somewhere as well. :confused:

Subtract the two & get on on with the next question... :eek:

[Ash767]

captainowie

Is the question just a stand alone i.e What will be your fuel burn from FL220 to FL350? Or is it an actual en route step climb as part of a flight plan from say YSSY - YPPH.

Ash767:)

[captainowie]

Ash.
The excercised I've been doing are stand alone, presumably with the intention to integrate them into an actual flight planning situation, although I can't think what difference that would make - It's not just a step climb, whereby one adds 50kg per thousand feet.

Cheers, Captainowie.

[captainowie]

Another question, this time in regards to fuel policy.
I understand that when in-flight re-planning of fuel situation following a positive fix, one no longer needs to include a taxi/shutdown allowance. Can anybody tell me why this might be the case? I imagine that the aircraft still needs to taxi in and shut down, so does the pilot eat into his fixed reserves?:confused:

Thanks for all responses to date,

Cheers, Captainowie

[Ash767]

captainowie

I was not sure if the question was part of an en route segment or just a tricky 2 marker. You are quite correct to allow 50kg/1000ft if it is a step climb.

In the exam they may ask you what would be your fuel burn or time taken to climb from FL220 to FL350 if this was the case Aussiebert and Tinstaafl are correct.

As for the T/S 100kg I can not answer your question fully. You do not need a positive fix for your T/S and fixed reserves. Once you are airborne and the wheels are up i.e in - flight you have an extra 100kg plus the fuel you save due to the reduction of you fixed reserves. I am speaking of course of normal ops for the reduction in fixed reserves.

Make sure you know the company policy like the back of your hand.

Regards
Ash767

[Aussiebert]

reason for the taxi/shutdown not being needed is *probobly* (read- i am assuming) because if you are fuel critical (which happens a lot more o/s than in australia), you need only plan to get the a/c on the runway safely, even though 100kg is not much, in a fuel critical situation its better to have it available in the air

Its much the same as the reductions in reserves for DP and OEI ops. Boeing have different recomended reserves for different types of operations as they are more/less critical.

In flight you have a fixed ammount of fuel available, preflight you can add more if its needed, hence in flight the reserves required are minimised. It ensures maximum range, more distant PNRs, etc.

Not that its relevant, but if you look at a 767 flight manual you'll see that the variable reserve goes up to a maximum of 2000kg.

[captainowie]

Thankyou all, most helpfull.
Watch this space for any further problems!

Cheers, Captainowie.

[RYAN TCAD]

I can't believe they're still basing all this stuff on the B727. 98% of us will probably never fly one!!

[Aussiebert]

why not, its about the same age as what most of us fly :p

a plane is a plane, having seen flight manuals for 737s and 767's there is little difference in format. Changing (which i hear they plan to, to the 767) would mean changing basically every atpl flight planning question, and checking they are all right. I would not like to be the first to do the new exam

[MoFo]

So what? They are public servants. Give em something to do for a change.