[SOLVED] FMS FLIGHT LOG PAGE - FUEL USED RESET

[richjb]

On the "Flying the Challenger" page, there is a question reseting the fuel used in the FMS.  On the Collins FMS that I flown, which includes the 6000 in the DA2000, The 5000 in the CL300 pre-PL21 Enhanced, and the 6200 in the CL300/CL350 with the PL21 Enhanced, all can reset the fuel used by using the DELETE key and then line selecting the DELETE over t he LSK for the FUEL USED. That action zeros the fuel used. 

I tried that today in HS CL650 and I got an INVALID DELETE MSG.  I'm not sure that's correct.  I check the latest edition of the Collins FMS manual for the CL60/650 and it does mention anything about the DELETE key zeroing the fuel.  For what it's worth, the CL350 PL Enhanced Collins FMS manual doesn't say anything either about the DELETE key zeroing the fuel on the FUEL USED field. I suspect that this is an undocumented feature of the Collins FMS, but I know that it does work. 

Might be something to confirm in the actual CL650, but I don't see why this FMS would work different for this particular page. 

For implementation if found to also work in the CL650.

Thanks,

Rich 

Edited April 1, 2022 by skiselkov

[skiselkov]

Implemented, will ship in update 1.5

[Pils]

@richjb Would you mind awfully explaining why one would want to do this? Thanks!

[richjb]

13 hours ago, Pils said:

@richjb Would you mind awfully explaining why one would want to do this? Thanks!

Sure!  Quick turn with no power down.  Yesterday, after leaving KELD I had two quick turns in KICT and KDEN before returning to KICT.  On each leg we never powered down, which normally re-sets the fuel used.  When you do not power down, the only way to reset the fuel used for each leg is to press the DEL key and put DELETE into the scratch pad. You then move the DELETE from scratch pad into the FUEL USED field with the LSK and that clears the fuel used and restarts the counter in the FMS.  That way, we can record how much fuel is used for current flight leg.  

Most operators track the fuel used on each leg.  They can track metrics like fuel used per flight mile, fuel used per hour which then goes into the DOC for the airplane for cost analysis and billing purposes.  Even part 91 corporate operators will usually bill back internally the per hour cost of the airplane to the unit using the airplane.  What I call "funny money" because it comes out of one group's budget and goes into another group's budget.   if you are flying charters, then it's very important to know the fuel burn per hour because that goes into the hourly charge for chartering the airplane.  

In a more practical "flying the airplane" sense, it is also important to know how much fuel has been burned from the start of the flight for the current flight leg.   Let's say you left on your oceanic flight with 15000 lbs. of fuel.  You're 2 hours into the flight and burned about 5000 lbs.   You should have 10,000 lbs. in the tanks.  if fuel gauges are showing 8000 lbs., you might have a problem. For example, a fuel leak.  You might be going down the line of Air Transat flight 236, the A330 that dead sticked into the Azores after a fuel leak developed.  Since that incident, most of the checklist for fuel imbalance have the pilots check for the possibility of a fuel leak by comparing fuel at block out minus the fuel used against the total fuel remaining in the tanks.  If they grossly disagree then you might want to 1) think twice about balancing fuel, i.e., feeding a fuel leak from the tank(s) not leaking, and 2) consider getting on the ground before things get real bad...and real quiet. 

Unfortunately, Collins doesn't mention using the DELETE to reset the FUEL USED in the FMS in the CL650 FMS manual that I have, and for what it's worth, it doesn't mention it in the current CL300/CL350 manual that I have.  In fact, the pages discussing the FLIGHT LOG CDU page in these two manuals are identical.  

I hope this helps!

Rich Boll 

 

[richjb]

On 3/31/2022 at 7:34 PM, skiselkov said:

Implemented, will ship in update 1.5

Thank you, sir!

Rich Boll

[JetNoise]

9 hours ago, richjb said:

Sure!  Quick turn with no power down.  Yesterday, after leaving KELD I had two quick turns in KICT and KDEN before returning to KICT.  On each leg we never powered down, which normally re-sets the fuel used.  When you do not power down, the only way to reset the fuel used for each leg is to press the DEL key and put DELETE into the scratch pad. You then move the DELETE from scratch pad into the FUEL USED field with the LSK and that clears the fuel used and restarts the counter in the FMS.  That way, we can record how much fuel is used for current flight leg.  

Most operators track the fuel used on each leg.  They can track metrics like fuel used per flight mile, fuel used per hour which then goes into the DOC for the airplane for cost analysis and billing purposes.  Even part 91 corporate operators will usually bill back internally the per hour cost of the airplane to the unit using the airplane.  What I call "funny money" because it comes out of one group's budget and goes into another group's budget.   if you are flying charters, then it's very important to know the fuel burn per hour because that goes into the hourly charge for chartering the airplane.  

In a more practical "flying the airplane" sense, it is also important to know how much fuel has been burned from the start of the flight for the current flight leg.   Let's say you left on your oceanic flight with 15000 lbs. of fuel.  You're 2 hours into the flight and burned about 5000 lbs.   You should have 10,000 lbs. in the tanks.  if fuel gauges are showing 8000 lbs., you might have a problem. For example, a fuel leak.  You might be going down the line of Air Transat flight 236, the A330 that dead sticked into the Azores after a fuel leak developed.  Since that incident, most of the checklist for fuel imbalance have the pilots check for the possibility of a fuel leak by comparing fuel at block out minus the fuel used against the total fuel remaining in the tanks.  If they grossly disagree then you might want to 1) think twice about balancing fuel, i.e., feeding a fuel leak from the tank(s) not leaking, and 2) consider getting on the ground before things get real bad...and real quiet. 

Unfortunately, Collins doesn't mention using the DELETE to reset the FUEL USED in the FMS in the CL650 FMS manual that I have, and for what it's worth, it doesn't mention it in the current CL300/CL350 manual that I have.  In fact, the pages discussing the FLIGHT LOG CDU page in these two manuals are identical.  

I hope this helps!

Rich Boll 

 

That definetly helped !! I was wondering about a scenario where to use this option and now its all clear ;-)

Thank you very much for the brief explanation, Rich ..

 

Oliver