Connect and get the inside scoop on Airline Companies

Welcome to Airline Pilot Forums - Connect and get the inside scoop on Airline Companies

If this is your first visit, be sure to check out the FAQ. Join our community today and start interacting with existing members. Registration is fast, simple and absolutely free.


User Tag List

Post Reply
 
Thread Tools Search this Thread
Old 01-19-2007, 02:46 PM   #1  
Banned
Thread Starter
 
fire's Avatar
 
Joined APC: Jan 2007
Posts: 62
Default Fuel Management???

Can somebody explain calculating holding times, and when you must divert? I ask captains often, but keep getting there answers mixed up. If it's in writing, it'll be easier for me to understand.

thanks in advance.
fire is offline  
Old 01-19-2007, 02:59 PM   #2  
Gets Weekends Off
 
320ToBearz's Avatar
 
Joined APC: Apr 2006
Posts: 361
Default

Quote:
Originally Posted by fire View Post
Can somebody explain calculating holding times, and when you must divert? I ask captains often, but keep getting there answers mixed up. If it's in writing, it'll be easier for me to understand.

thanks in advance.
it's a judgement call, thats why the 4 stripers get paid the "big" bucks. some companies may have hard rules written in their operating procedures though. usually fuel is looked at every 10-15 minutes in the hold.

each CA has their own different personal minimums when it comes to fuel, while the FAA minimums are strictly a dispatching function.

in general, you get to your reserve of 45 minutes of fuel in a light ifr or vfr day, then you divert. add the furthest alternate fuel to that if it is hard ifr in the surrounding area. ie, build margins into it. coordinate with dispatch as they sometimes have a better bigger picture when it comes to weather.
320ToBearz is offline  
Old 01-19-2007, 08:12 PM   #3  
New Hire
 
Joined APC: Jan 2007
Position: looking
Posts: 9
Default

Quote:
Originally Posted by fire View Post
Can somebody explain calculating holding times, and when you must divert? I ask captains often, but keep getting there answers mixed up. If it's in writing, it'll be easier for me to understand.

thanks in advance.
Flying for a B737NG operator, we plan a landing fuel of 5000 lbs plus our alternate airport fuel, usually around 1500 lbs give or take. We burn about 5000 lbs per hour, so when our FMC reserves page tells us we are going to land at our alt. with 5000 lbs we (I) boggie. It just depends how much fuel you have when you start to hold. 1250 lbs is about 15 minutes and so on. As the previous post said it depends on the Capt as well. What I'm comfortable with might not make another Capt as comfortable.
Highspeedclimb is offline  
Old 01-19-2007, 09:49 PM   #4  
Che Guevara
 
ToiletDuck's Avatar
 
Joined APC: Aug 2005
Posts: 6,363
Default

What's the companies position on crew members making the decision to leave? Do they make you call in and ask before you hit your minimums or do you just call in and tell them. IE. You have 25min fuel before FAA requires you to divert but you want to do it now.
ToiletDuck is offline  
Old 01-19-2007, 11:43 PM   #5  
New Hire
 
Joined APC: Jan 2007
Position: looking
Posts: 9
Default

You're on your own. Never been called by the CP regarding departing to our alternate with said amount of fuel, but do know someone who was called because he landed at his alternate with 9500 lbs, or about 1:45 of fuel left. This with the alternate being 18 minutes from the intended original airport. I would say he left a little early but then again I don't know the particulars. Possibly the approach was down for maint. etc...
Highspeedclimb is offline  
Old 01-20-2007, 08:53 AM   #6  
Flying Farmer
 
Ewfflyer's Avatar
 
Joined APC: Jul 2006
Position: Turbo-props' and John Deere's
Posts: 3,159
Default

Quote:
Originally Posted by 320ToBearz View Post
it's a judgement call, thats why the 4 stripers get paid the "big" bucks.
Exactly why they are called the PIC!!!!! The final authority!!!

There are always suggested, and sometimes required, but most pilots aren't going to go to Min Fuel before they make that decision. I've landed with my 45 min remaining before and wasn't really comfortable with it, but it was daylight and clear, just a stronger headwind than predicted. Something I'll pass on next time and just get some more gas.
Ewfflyer is offline  
Old 01-20-2007, 09:55 AM   #7  
Gets Weekends Off
 
shackone's Avatar
 
Joined APC: May 2006
Posts: 356
Default

Quote:
Originally Posted by 320ToBearz View Post
in general, you get to your reserve of 45 minutes of fuel in a light ifr or vfr day, then you divert.
Just to be on the safe side, I think you had better start that divert sooner.

For Part 121 jet ops, you'll need to plan to divert with fuel enough to get to the divert location and then have 45 minutes of fuel on board. The 45 minutes of fuel is what you plan to land with...not when you start the divert.


For Fire...

Figure out what a typical fuel burn number is for your airplane when holding...figure it for 'x' amount of fuel per minute. That value will allow you to easily figure your burn while holding.

Then figure out a typical burn (in 'x' amount per minute) for cruise...the cruise, for example, that you would use when diverting from a hold to a divert/alternate. Figure out your average ground speed in miles per minute in this divert cruise (no wind). Compute the divert distance, divide this by your estimated cruise ground speed in minutes. This gives you ETE to the divert/alternate (no descent planned just to be conservative). Then multiply the ETE times your cruise burn rate to get the estimated enroute burn. Add your FAA reserve fuel to this value to arrive at the divert fuel.

For example:

Cruise burn = 100#/minute. Cruise ground speed (no wind) = 4nm/minute.

Distance from the hold to the divert/alternate = 100nm.

ETE = 100 divided by 4 = 25 minutes.

Cruise burn = 25 minutes X 100#/min = 2500#.

If your reserve was 3000#, then your divert fuel = 3000# + 2500# = 5500#.

Now, let's say your estimated holding burn was also 100#/min. You are in the hold with 7500# remaining. You want to divert at 5500#. You have 2000# to burn in the hold...at 100#/min, this equals 20 minutes of holding time before you divert.

Maybe others can add their techniques!

Last edited by shackone; 01-20-2007 at 09:57 AM. Reason: typos
shackone is offline  
Old 01-20-2007, 10:30 AM   #8  
Banned
Thread Starter
 
fire's Avatar
 
Joined APC: Jan 2007
Posts: 62
Default

thanks alot guys. much appreciated
fire is offline  
Old 01-20-2007, 05:14 PM   #9  
Gets Weekends Off
 
320ToBearz's Avatar
 
Joined APC: Apr 2006
Posts: 361
Default

oops i meant get to your vfr or ifr reserve + the enroute burn to the diversion airport. duh.
320ToBearz is offline  
Old 01-20-2007, 05:34 PM   #10  
Gets Weekends Off
 
shackone's Avatar
 
Joined APC: May 2006
Posts: 356
Default

Not to worry. When we give the oral examination as part of the type check, it's discouraging to see the general lack of understanding regarding reserve fuel among the candidates...some of whom have been flying Captain for several years.
shackone is offline  
 
 
 

 
Post Reply
 



Thread Tools Search this Thread
Search this Thread:

Advanced Search


Related Topics
Thread Thread Starter Forum Replies Last Post
JetBlue pushing the way, how many would follow? ToiletDuck Major 32 12-21-2006 02:23 PM
Boeing 777 Freighter prezbear Cargo 31 11-05-2006 08:12 AM
Fuel Costs Drag on JetBlue LeeFXDWG JetBlue 16 05-02-2006 08:30 AM
AA costs going up, not just over fuel RockBottom Major 3 02-24-2006 02:05 PM
Fuel costs bedevil airlines SWAjet Major 0 02-26-2005 11:49 AM


All times are GMT -8. The time now is 06:26 AM.