The great big "ask an airline pilot" thread!

Growler!!! · 22-05-2014 08:03AM

ProfessorPlum wrote: »

Well now, that's going to cause a row!

I was referring to myself:D

eatmyshorts wrote: »

Contingency fuel can be used after the fuel bowser is disconnected, so it is legally possible to dispatch without having it on board.

I'll have to check that out.
My understanding is that Contingency fuel is included in the total at the bottom of the plog ie. it is needed for dispatch. Could be due to different ops procedures as my company use 5% of trip fuel, there are other methods mentioned in OMA. Looks like my poor F/O will be learning about fuel today on the longer sectors;)

youknowwho · 22-05-2014 08:34AM

Does "taxi" fuel include running the APU while sitting on the ground. In bad weather a plane could be just sitting for quite a while or do they wait until a fix time before departure to fill the tanks with the calculated fuel load?

billie1b · 22-05-2014 08:47AM

youknowwho wrote: »

Does "taxi" fuel include running the APU while sitting on the ground. In bad weather a plane could be just sitting for quite a while or do they wait until a fix time before departure to fill the tanks with the calculated fuel load?

While the a/c is sitting on the ground at the gate, its connected to a GPU (Ground Power Unit), it enables the plane to be powered up without the use of the a/c's APU (using no fuel). Some GPU's are mobile and powered by diesel, some are in ground GPU's and powered by electricity. Some a/c could be fuelled up 6 hours before the departure time and not use a drop of fuel until pushback.

bkehoe · 22-05-2014 01:33PM

youknowwho wrote: »

Does "taxi" fuel include running the APU while sitting on the ground. In bad weather a plane could be just sitting for quite a while or do they wait until a fix time before departure to fill the tanks with the calculated fuel load?

Yes, but APU fuel usage is minimal (in the region of 100KG/hr on a 737/320, but depends on whether its used for electrical power only, or air conditioning as well) on normal sectors as billie already mentioned. In some airports we'd leave the APU running for the turnaround if there is no ground power available, or if the cabin is too hot or too cold (even though some airports supply conditioned air, sometimes it seems as if they may as well just give you a fan to blow the hot air around!).

Also, in some airports (e.g. BCN, MAD) there are strict noise regulations on when you can run the APU - e.g. only 5 minutes before departure.

My understanding of contingency is that it's required at the point of commencing the takeoff run.

Jack1985 · 22-05-2014 02:06PM

Is the 5% EU-OPS contingency included regardless of discretionary contingency fuel?

ProfessorPlum · 22-05-2014 03:34PM

Jack, what exactly do you mean by 'discretionary contingency fuel'?

Here's the relevant bit from EU ops (1.255). As an aside, the required contingency doesn't have to be 5%, operators may be allowed to use 3% if they have an en route alternate, and there are other methods of calculating reduced contingency fuel.

http://www.skybrary.aero/bookshelf/books/818.pdf

An operator shall ensure that the pre-flight calculation of usable fuel required for a flight includes:
1. Taxi fuel; and
2. Trip fuel; and
3. Reserve fuel consisting of:
(i) contingency fuel (see OPS 1.192); and
(ii) alternate fuel, if a destination alternate aerodrome is required. (This does not preclude selection of the depar- ture aerodrome as the destination alternate aerodrome); and
(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.

smurfjed · 22-05-2014 03:44PM

Do you have any rules pertaining with the selection of an alternate? I have seen people use Orly as an alternate for LeBourget so the resulting figures are about 4 minutes flight time and 24 miles. To me this isn't adequate, so I'm interested in knowing if there are any European rules dealing with this?

ProfessorPlum · 22-05-2014 03:52PM

smurfjed wrote: »

Do you have any rules pertaining with the selection of an alternate? I have seen people use Orly as an alternate for LeBourget so the resulting figures are about 4 minutes flight time and 24 miles. To me this isn't adequate, so I'm interested in knowing if there are any European rules dealing with this?

There are lots of rules for selection of alternates as you can image, but there is nothing to stop you selecting one right next door. In fact, if you look at the regulations, you may not have to select one at all (our company policy is always to select at least one alternate, and usually 4 are selected). As Growler said above, a prudent captain may take more fuel than required, so in my experience, for example, if weather at destination is an issue, and the nominated alternated is close to destination, we will take fuel for a further alternate.

Jack1985 · 22-05-2014 05:17PM

ProfessorPlum wrote: »

Jack, what exactly do you mean by 'discretionary contingency fuel'?

Here's the relevant bit from EU ops (1.255). As an aside, the required contingency doesn't have to be 5%, operators may be allowed to use 3% if they have an en route alternate, and there are other methods of calculating reduced contingency fuel.

http://www.skybrary.aero/bookshelf/books/818.pdf

An operator shall ensure that the pre-flight calculation of usable fuel required for a flight includes:
1. Taxi fuel; and
2. Trip fuel; and
3. Reserve fuel consisting of:
(i) contingency fuel (see OPS 1.192); and
(ii) alternate fuel, if a destination alternate aerodrome is required. (This does not preclude selection of the depar- ture aerodrome as the destination alternate aerodrome); and
(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.

Cheers for that, should have been clearer, I was referring to discretionary as the captains final reserve outside of regulation requirements.

StevieNicksFan · 22-05-2014 05:32PM

crazygeryy wrote: »

bit of a weird one but someone might know.

what is the name for the "kite" like thing at mainly small airports that gauges how soft or strong the wind is?
its shaped like a tube that has a big opening at one end(where the wind goes in) and small opening at the other end and is attached to a stick thats stuck into the ground.

god i hope im explaining this well enough.:rolleyes:

A windsock? http://en.wikipedia.org/wiki/Windsock

bkehoe · 22-05-2014 06:57PM

smurfjed wrote: »

Do you have any rules pertaining with the selection of an alternate? I have seen people use Orly as an alternate for LeBourget so the resulting figures are about 4 minutes flight time and 24 miles. To me this isn't adequate, so I'm interested in knowing if there are any European rules dealing with this?

Many, probably most, airlines will have a policy for the minimum amount of reserve fuel to carry. My airline has such a policy, so even if something tiny like 600kg is needed for the alternate, there will be extra already added on automatically to ensure there's never less than the minimum amount decided by the company.

the_monkey · 22-05-2014 08:39PM

Hi , the plane at the start of this video here is an A340 yeah ?

http://www.youtube.com/watch?v=gTuTIkO2R1w

Seems strange they flew on an A340 from Munich - London ..

Jack1985 · 22-05-2014 09:52PM

the_monkey wrote: »

Hi , the plane at the start of this video here is an A340 yeah ?

http://www.youtube.com/watch?v=gTuTIkO2R1w

Seems strange they flew on an A340 from Munich - London ..

Chartered flight.

ProfessorPlum · 23-05-2014 12:00AM

bkehoe wrote: »

Many, probably most, airlines will have a policy for the minimum amount of reserve fuel to carry. My airline has such a policy, so even if something tiny like 600kg is needed for the alternate, there will be extra already added on automatically to ensure there's never less than the minimum amount decided by the company.

All airlines must have a fuel policy which is approved by the authority which they operate under. The final reserve fuel is a legally defined amount (time) and is separate and independant of the alternate fuel. I think your use of terminology might be confusing for those not completely familiar with the process.

bkehoe · 23-05-2014 07:50AM

ProfessorPlum wrote: »

All airlines must have a fuel policy which is approved by the authority which they operate under. The final reserve fuel is a legally defined amount (time) and is separate and independant of the alternate fuel. I think your use of terminology might be confusing for those not completely familiar with the process.

For clarification, I was referring to the total amount of reserve fuel, not just final reserve.

the_monkey · 23-05-2014 09:39AM

Jack1985 wrote: »

Chartered flight.

But still an A340 right ?

...

amen · 23-05-2014 12:53PM

Jack1985 wrote: »

Chartered flight.

While it may be charted you could also see a wide body on a short flight if
1: New type entering service i.e. BA flew the A380 London/Paris for training and then expanded to other routes
2: Maybe a smaller plane went technical at a remote location and multiple flights at that location impacted. Makes more sense to send a single wide body to pick up all the passengers in a single trip.

Jack1985 · 23-05-2014 04:54PM

the_monkey wrote: »

But still an A340 right ? ...

Yep

amen · 04-06-2014 12:44PM

The speed of sound decreases with altitude and decreasing temperature.

As as the planes altitude increases do you see an increasing mach number or do you always fly to an specific mach number irrespective of altitude or are you just flying to IAS (in knots) ?

eatmyshorts · 04-06-2014 01:30PM

amen wrote: »

The speed of sound decreases with altitude and decreasing temperature.

As as the planes altitude increases do you see an increasing mach number or do you always fly to an specific mach number irrespective of altitude or are you just flying to IAS (in knots) ?

Flying at a constant IAS, Mach No will increase as the aircraft climbs.
In a climb we will hold 320kts until that equals M0.83 (approx FL290). Then climb at a constant M0.83 so the IAS will then begin to decrease.

Growler!!! · 04-06-2014 02:33PM

amen wrote: »

The speed of sound decreases with altitude and decreasing temperature.

Just to be pedantic. LSS is dependent on temperature ONLY. In an inversion temperature does not decrease with altitude.

basill · 04-06-2014 02:40PM

It will largely depend on how the respective company wishes you to fly their aircraft. Ours prefers an economy climb based on a specific cost index from the flight plan. By leaving the speed "managed" the airbus will climb initially at a set of fixed speeds till the changeover point and then fly at a Mach No. Of course airmanship on the day may mean that we select a climb speed and/or Mach for wx avoidance or to facilitate an ATC request etc.

amen · 05-06-2014 11:06AM

LSS is dependent on temperature ONLY

So if for instance you are flying along at 10,000m and Mach .083 (with your decreased IAS) and there was very very cold weather would it be possible for your plane to be flying at the required Mach Number but with an IAS that is now close to the stall speed of the aircraft ?

Growler!!! · 06-06-2014 08:16AM

amen wrote: »

So if for instance you are flying along at 10,000m and Mach .083 (with your decreased IAS) and there was very very cold weather would it be possible for your plane to be flying at the required Mach Number but with an IAS that is now close to the stall speed of the aircraft ?

What you're talking about there is Coffin Corner.

http://en.wikipedia.org/wiki/Coffin_corner_(aerodynamics)

TheBoss11 · 06-06-2014 08:22AM

Okay so, I got the opportunity to get a spin the the a320 sim in simtech recently. Without a doubt the best experience of my life, way better than I expected!! My question is though. After years of flying does it get boring as an airline pilot?

basill · 06-06-2014 09:14AM

Thats a tough one. I think it depends on a number of factors....

- your own expectations of the job when you started out
- the airline you fly with - route network, fleet size/type, its rules and regulations
- the people you work with
- your own personality/ability to have a laugh and enjoy the day to day stuff

For me I went into the industry knowing a few people so was fully aware that there would be little hand flying and it was more about managing the operation. I had no problem with this.

On the other hand if you were an introvert who was unable to hold a conversation, had little or no personality and your flying ability was suspect then I would say being locked in a cockpit for 12 hours might not be the best place for you.

eatmyshorts · 06-06-2014 09:40AM

basill wrote: »

On the other hand if you were an introvert who was unable to hold a conversation, had little or no personality and your flying ability was suspect then I would say being locked in a cockpit for 12 hours might not be the best place for you.

There's a few of them around though, like the FO I flew with on a 9 hour 2-man sector the other week.

basill · 06-06-2014 09:46AM

There is an easy solution to that issue. "I will take it out and you can do the radios on the way back!":)

Jack1985 · 06-06-2014 11:59AM

eatmyshorts wrote: »

There's a few of them around though, like the FO I flew with on a 9 hour 2-man sector the other week.

Don't airlines try to avoid recruiting people like that? Not that it's illegal to not hold a conversation or have some sort of a personality but in the interests of a relaxed atmosphere in terms of conversation? God I wouldn't be able to handle 9 hours with someone like that.

keith16 · 06-06-2014 03:44PM

Is there any real difference between P&W and RR engines?

Why would an airline choose one over the other?

The great big "ask an airline pilot" thread!

Comments