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-   -   Minimum fuel at alternate (https://www.pprune.org/tech-log/267865-minimum-fuel-alternate.html)

Danil 13th Mar 2007 15:46

Minimum fuel at alternate
 
As you know there are regulations regarding the minimum fuel required for a specific operation. What is not mandated is the required fuel when you land at the alternate after diversion followed by a holding of 30 minutes. If you take only the minimum fuel required on the Operational flight plan and the scenario described above is actually happening, then you will land with 0 Kg of fuel. It is a bit awkward. To my understanding this is left to the Operator.
I would appreciate if you can tell me what procedure is your Company applying?
.

zon3 13th Mar 2007 16:17

Dani,

the Final reserve is the fuel required to hold for 30 minutes at the alternate. If you expect to land (at destination, alternate or other airfield) with less than Final reserve, you should declare an emergency.

Using up your Final reserve in a holding pattern sounds like a bad choice to me! :uhoh:

EGPFlyer 13th Mar 2007 16:20

The previso is that you wouldn't hold at your alternate except if the brown stuff really is hitting the fan. Once you get down to diversion fuel plus final reserve then you should be diverting, definitely on a PAN if you may land below final reserve.

RYR-738-JOCKEY 13th Mar 2007 16:27

I see your point, but you will also land with the 5% contingency fuel. This is the minimum required by law, and from experience this has proven to be satisfactory for most situations. And what you finally choose to carry, is to be constantly re-evaluated by the commander during the duration of the flight, so you don't end up with less than desired...

Wizofoz 13th Mar 2007 16:40


but you will also land with the 5% contingency fuel. This is the minimum required by law,
No, you will UPLOAD 5% contingency, but this may be used at any time after the bowser dis-connects.

Holds on the ground, weather divertions,non optimal levels etc. may all mean you use contingency fuel before arrival. The only requirement is that you land with 30 mins final reserve.

RYR-738-JOCKEY 13th Mar 2007 17:01

Wizofoz: You're of course 100% correct. You're in the left seat, I presume ;-)

FE Hoppy 13th Mar 2007 17:18


but this may be used at any time after the bowser dis-connects.
Not exactly correct!
Check the many threads on dispatch.

Wizofoz 13th Mar 2007 18:03

FE,

Rather than check threads on PPRUNE, I've checked my FOM!!

Perhaps different rules apply depending on where you operate, but what I wrote is correct by the rules I operate under, and broadly correct (with suibtle variations as you point out) under JAR compliant operations.

popay 13th Mar 2007 19:15

Hi there, JAR OPS doesn't distinguish between landing at destination or alternate or anywhere else. All one needs to have is final reserve upon touch down anywhere.
Here is the reference JAR-OPS 1.375 In-flight fuel management
(a) An operator shall establish a procedure to
ensure that in-flight fuel checks and fuel management
are carried out.
(b) A commander shall ensure that the amount
of usable fuel remaining in flight is not less than the
fuel required to proceed to an aerodrome where a
safe landing can be made, with final reserve fuel
remaining.
(c) The commander shall declare an emergency
when the actual usable fuel on board is less than final
reserve fuel.
In other words regardless of where one lands make sure one has got final reserve on board upon touch down or if the engines flamed out upon touch down make sure one had declared emergency when it became obvious the final reserve will be consumed.:ok:
Cheers.

Max Angle 13th Mar 2007 20:08

You are quite correct but only if you are using an old style non-jaa fuel policy. For many years we used the old CAA policy that required (if I remember correctly) fuel to divert from your destination (missed approach point) and divert to your alternate, hold for 20 minutes (could have been 30) and then make an approach. You could have in theory have held for 20 minutes and landed with nothing and still have been legal. You were also obliged to divert when you got down to alternate + alternate holding fuel rather than, under certain circumstances, ditching the alternate and continuing to hold at your destination using that fuel. In practice of course if you had diverted and were told there was 20 minutes holding you would (should) have declared an emergency and landed anyway. The newer policy just formalises that process and says that you if you expect to land at your destination or alternate with less than 30 minutes holding fuel you MUST declare a mayday.

Fredairstair 14th Mar 2007 10:56

This might sound obvious but if you take Flight Plan Fuel on a Jar-ops plan, you do not have any holding fuel, you have Final Reserve Fuel. Which is a different thing alltogether.

ElNino 14th Mar 2007 16:43

Some (most?) airlines mandate a certain fuel level below which a PAN or MAYDAY becomes obligatory. As this level is (usually) above the final reserve fuel level, in practical terms I think people would aim to divert and land at slightly above the PAN level, in order to avoid being forced into declaring PAN/MAYDAY. Of course it's perfectly legal to go below said level and plan on landing with final reserve fuel.

Intruder 14th Mar 2007 19:47

Our SOP (747) has 7,000 KG min at alternate.

alexban 14th Mar 2007 20:19

Minimum required at destination is alternate fuel plus final reserve. Route reserve may be used during flight (for ex for weather avoidance,different FL,etc..) .
Arriving at alternate you will have the final reserve remaining on board.According with regulations ,this is the fuel at which you should declare an emergency- MAYDAY.
If you'll have to hold at alternate,you are in for some trouble.You should've anticipated this well before arriving to alternate and plan for alternate scenario.For ex don't hold at destination untill you arrive at minimum fuel OHD if the alternate presents some chances of poor weather also.Or plan for 2 alternates if weather seems to be a problem around ETA.
In any case you should avoid putting yourself into a corner by any means.

TheGorrilla 14th Mar 2007 22:03

Assuming you've burn't taxi fuel on the way out, all the trip fuel in getting to destination, all contingency sometime after engine start, gone around from DH at destination, diverted to your alternate, held for half an hour having not loaded any extra fuel prior to departure, your tanks would be empty!! Hence the mayday call if you touch the half hour final reserve fuel or pan call if you think you may touch it.

CJ Driver 14th Mar 2007 23:56

Final Reserve isn't for holding!
 
It is mildly disturbing, but perhaps not surprising, to see the usual confusion between fuel for holding and the final reserve. All JAR-OPS operators are required to define in their Ops manual an amount of fuel which they will always (except in an all-out emergency) have on board when they land - including when they land at their alternate. Because you need to come up with some simple mathematical numbers and you can't allow for all possible conditions, a convenient answer has tended to be "that amount of fuel that I would burn if I flew for 30 minutes at normal holding power". If you fly only a single type that can then be translated easily - you just have a number (apparently 7000 kg in Intruder's 747) - although many pilots seem to "remember" the bit about 30 minutes of holding. BUT - just because somebody in the office came up with a number that used concepts like "30 minutes" and "holding" does NOT mean that you can use your final reserve to hold for 30 minutes! In fact the only fuel you can use for holding is the "extra" fuel you have on board. Extra fuel is the fuel over and above the fuel to destination, diversion fuel and final reserve.

alexban 15th Mar 2007 08:31

CJ :
From jarops: "
An operator shall ensure that the pre-flight
calculation of usable fuel required for a flight
includes:
(1) Taxy fuel;
(2) Trip fuel;
(3) Reserve fuel consisting of:
(i) Contingency fuel (see IEM OPS
1.255(c)(3)(i));
(ii) Alternate fuel, if a destination
alternate is required. (This does not
preclude selection of the departure
aerodrome as the destination alternate);
(iii) Final reserve fuel; and
(iv) Additional fuel, if required by
the type of operation (e.g. ETOPS); and
(4) Extra fuel if required by the
commander."
regarding final reserve:"
1.5 Final reserve fuel, which should be:
a. For aeroplanes with reciprocating engines, fuel to fly for 45 minutes; or
b. For aeroplanes with turbine power units, fuel to fly for 30 minutes at holding speed at 1 500 ft
(450 m) above aerodrome elevation in standard conditions, calculated with the estimated mass on arrival at
the alternate or the destination, when no alternate is required." (Jarops1-section2)
So,CJ ,I think it's not a confusion between final reserve and fuel to hold for 30 min,cause this is what it is.Fuel to hold for 30 min at 1500'.(or to fly at holding speed for 30 min).
Indeed,you won't hold for 30 min,untill tanks are dry,but you have to know the max amount of time you'll have ,which is less than 30 min,considering gliding after that..:} , so a MAYDAY when arriving at alternate ,with just final reserve,is compulsory!

212man 15th Mar 2007 08:43

Alex, re-read your own quotes: It's not holding fuel, it's fuel to fly for 30 minutes (at holding speed).

It's simply a means of defining what fuel consumption you should apply to calculate what 30 minutes fuel actually is!

Fredairstair 15th Mar 2007 10:06

missed approach on min fuel
 
This confusion could explain why some of my colleagues will brief (when arriving with min fuel) "If we do a missed approach, we'll take up the hold". When asked how much 'holding' fuel we have, they reply "we've got 30 min"

:ugh:

If you choose to depart with flight plan fuel, you do NOT have any holding fuel.

And another thing...... how much of that 30 min do we think is useable?

john_tullamarine 15th Mar 2007 10:44

All should be usable as the unusable is a certification quantity detemined by flight test and reasonably representative of non-extreme flight. Whether you might get the 30 minutes time is another matter ... and why would you even contemplate doing it ?


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