Dumb question - fuel draining when over W & B?
Thread Starter
Join Date: Aug 2007
Location: Suffolk
Age: 70
Posts: 283
Likes: 0
Received 0 Likes
on
0 Posts
Dumb question - fuel draining when over W & B?
Just looking at weight and balance calc (for a Piper Tomahawk using this very useful spreadsheet from Leading Edge in Scotland) According to that, with two PoB each weighing 200lb, only about 20lt of fuel can be in the tanks.
So this could mean draining some fuel. I've never been around when anyone has done this - so, dumb questions:
1. How do you drain the fuel (esp if it's a low wing plane and gravity isn't going to be a help)?
2. Where do you do with it then?
So this could mean draining some fuel. I've never been around when anyone has done this - so, dumb questions:
1. How do you drain the fuel (esp if it's a low wing plane and gravity isn't going to be a help)?
2. Where do you do with it then?
Join Date: Feb 2007
Location: Yateley, Hants
Posts: 31
Likes: 0
Received 0 Likes
on
0 Posts
I guess i'm dumb too so hypothetically though a scenario that could happen.
So supposing I've booked a plane and made a specific request that it isn't topped up before my hire but this isn't taking note of. I only wanted say 100litres and the plane now has 150 making it too heavy for my intended flight.
Short of blowing a gasket and moaning and because there isn't another available, is it realistically possible to drain off without causing a problem?
I'm sure there will be lots of flak now for being a dumba**e so i've got me flak jacket on and am ready to leave the room!
So supposing I've booked a plane and made a specific request that it isn't topped up before my hire but this isn't taking note of. I only wanted say 100litres and the plane now has 150 making it too heavy for my intended flight.
Short of blowing a gasket and moaning and because there isn't another available, is it realistically possible to drain off without causing a problem?
I'm sure there will be lots of flak now for being a dumba**e so i've got me flak jacket on and am ready to leave the room!
Join Date: Aug 2000
Location: Norfolk
Posts: 1,966
Likes: 0
Received 0 Likes
on
0 Posts
defuelling can happen with airliners, where there are strict rules about reusing the defuelled product ONLY in the same company's aircraft - all to do with Cladisporium Resinae, a bug that loves Jet A-1.
In my aircraft, I often syphon 20 or 40 litres off into one or two jerry-cans to bring the AUW down into the aerobatic envelope if taking someone for a ride.
Kit required, clean length of hose (Avgas compatible, such as B&Q garden hose), one or two jerry-cans and an ability to suck hard on the hose! I let my g/f do this.
Not a silly question, at all.
Stik
In my aircraft, I often syphon 20 or 40 litres off into one or two jerry-cans to bring the AUW down into the aerobatic envelope if taking someone for a ride.
Kit required, clean length of hose (Avgas compatible, such as B&Q garden hose), one or two jerry-cans and an ability to suck hard on the hose! I let my g/f do this.
Not a silly question, at all.
Stik
Join Date: Mar 2007
Location: Right here
Age: 50
Posts: 420
Likes: 0
Received 0 Likes
on
0 Posts
Or you can do what I saw at the airport just the other day... Guy comes up on the tower frequency, says they have too much fuel to make MTOW and need to burn some off before takeoff... So this fancy Citation Excel (I think, or something similar) ended up sitting in the remote runup area for 45 minutes turning Jet-A1 into noise and smoke... Brilliant! 
Join Date: Dec 1999
Location: Oop North, UK
Posts: 3,076
Likes: 0
Received 0 Likes
on
0 Posts
I think you will find strictly speaking that once in an aircraft the fuel should not be reused for aircraft use if drained, even commercially I think you will find it is used for things like fire training so putting it back in is not allowed and you should use it for the lawn mower or something. Privately a lot of people will put it back in, clubs and schools will vary on how legal they stay
Thread Starter
Join Date: Aug 2007
Location: Suffolk
Age: 70
Posts: 283
Likes: 0
Received 0 Likes
on
0 Posts
for jockeys only
According to the speadsheet, two moderately weighing people (200 lb each - moderatly fat bastards) would get about 50 min endurance. Which is not a lot.
That surprises me - as a training acft, operating within W & B must be a problem. Or am I overlooking something here?
I'd like to understand this - so will take ridicule if it leads to clarity.
That surprises me - as a training acft, operating within W & B must be a problem. Or am I overlooking something here?
I'd like to understand this - so will take ridicule if it leads to clarity.
Join Date: Sep 2005
Location: North of South
Posts: 831
Likes: 0
Received 0 Likes
on
0 Posts
Its true , you actually run the risk of failing your gft if you dont point out to the examiner that you are actually over weight when flying a PA38. As far as I am aware this is pretty much always the case with full fuel and fat gits like me in the left seat .
Join Date: Feb 2007
Location: Amsterdam
Posts: 4,598
Likes: 0
Received 0 Likes
on
0 Posts
There was a discussion about this in the airliners forum. Precisely because the fuel cannot be reused for aircraft use until tested extensively, and airports don't have spare holding tanks available (so they've got to give up a bowser, which needs to be cleaned and tested afterwards), and defueling takes ages, it is cheaper to just burn off the excess fuel than to remove it.
As for removing fuel from a GA aircraft - you can siphon it off or use the fuel drains. Both will be somewhat messy and take some time. Fortunately our club doesn't have a "refuel after flight" policy and it rarely happens that a plane has too much fuel on board. In fact, on the first page of the log book of our R2160 (the only aero plane in the fleet) we've now written in bold letters never to return the aircraft with more than 1/2 fuel or otherwise it'll be out of the aeros W&B envelope. You can't miss that warning, as it is right next to the plastic sleeve that holds the fuel credit card.
As for removing fuel from a GA aircraft - you can siphon it off or use the fuel drains. Both will be somewhat messy and take some time. Fortunately our club doesn't have a "refuel after flight" policy and it rarely happens that a plane has too much fuel on board. In fact, on the first page of the log book of our R2160 (the only aero plane in the fleet) we've now written in bold letters never to return the aircraft with more than 1/2 fuel or otherwise it'll be out of the aeros W&B envelope. You can't miss that warning, as it is right next to the plastic sleeve that holds the fuel credit card.
Join Date: Feb 2006
Location: Daventry
Posts: 349
Likes: 0
Received 0 Likes
on
0 Posts
Fuel Overload
Booked a 152 for me and a mate,requesting a low fuel state so I could fuel it to correct weight.Guess what-insomniac bowser driver comes real early and fills all club a/c to max
before I got there.Had to fly around on my own for 30mins (and pay for it+landing fee) before he could hop in-late to destination and a not too impressed pax.
MM
before I got there.Had to fly around on my own for 30mins (and pay for it+landing fee) before he could hop in-late to destination and a not too impressed pax.MM
Why do it if it's not fun?
Join Date: Jul 2001
Location: Bournemouth
Posts: 4,779
Likes: 0
Received 0 Likes
on
0 Posts
I had to de-fuel a Piper Arrow a few years ago, for my CPL skills test. Not 100% sure how they did it, I think they jammed the fuel drains open. No idea what happened to the fuel afterwards.
In my case, I'd asked for it to be filled to tabs, and done my w+b calcs with it filled to tabs. The previous pilot had filled it up to the top, expecting to burn off enough fuel to get it to tabs for my test. Unfortunately, the aircraft went tech, so the previous pilot didn't fly it at all. The tech problem was fixed for my test, but the tanks were still full. I re-did the w+b calcs and found that we were out of CofG limits - and adding the ballast required to bring CofG into limits would have taken us over the MTOW. The school were not pleased - but with the examiner waiting, they didn't really have any option except to take fuel out!
FFF
---------------
In my case, I'd asked for it to be filled to tabs, and done my w+b calcs with it filled to tabs. The previous pilot had filled it up to the top, expecting to burn off enough fuel to get it to tabs for my test. Unfortunately, the aircraft went tech, so the previous pilot didn't fly it at all. The tech problem was fixed for my test, but the tanks were still full. I re-did the w+b calcs and found that we were out of CofG limits - and adding the ballast required to bring CofG into limits would have taken us over the MTOW. The school were not pleased - but with the examiner waiting, they didn't really have any option except to take fuel out!
FFF
---------------
Join Date: Sep 2006
Location: 10 west
Posts: 325
Likes: 0
Received 0 Likes
on
0 Posts
Hi Rusty,
we used PA38 for 15 years in a flying school. generally we were not over gross, but sometimes a little for the first lesson ( and we should not have been even a little but look in the real world it happens..but you should'nt do it...if there is an accident on the first take off, the first thing the accident investigator is going to do is determine the weight and establish the centre of gravity ).
i even had to refuse a trial lesson one day because the guy was just too heavy. apart from the difficulty of physically getting him into the aircraft, i worked out i could carry no fuel at all with both of in the aircraft so it just was'nt on. he was pi$$ed...but all you can do in that situation is move him up to a bigger aircraft.
regarding your point that gravity wo'nt help....of course it will. surely you know the fuel drains are on the bottom ot the tank. open them and gravity does the rest.
as regards re-using that fuel...we never...ever..ever..did that. the engineering boys got that to wash things down. you can't dump it and you certainly should never put it back in the tank even if it has been drained into something spotless. fuel in JAAland and presumably where you are must only be supplied to aircraft from an approved fuel installation...which your jerrycan is not.!!
for flight testing we had to use PA28 or else in exceptional circumstances ( if weight permitted )we might agree as examiners to split the flight test into two.generally the candidate is told to ensure that as the flight test lasts about two hours to ensure that three hours fuel was on board ( though the latter part of the test is generally conducted at an airfield )...but is possible sometimes to do the navex first, refuel and then do the upper airwork. its far from ideal ( say in a situation where the navex if failed it can create complications )...but to facilitate sometimes one has to try to accomodate otherwise nothing gets done..
the fact you asked shows you are thinking...good for you..
fly safe..
the dean.
we used PA38 for 15 years in a flying school. generally we were not over gross, but sometimes a little for the first lesson ( and we should not have been even a little but look in the real world it happens..but you should'nt do it...if there is an accident on the first take off, the first thing the accident investigator is going to do is determine the weight and establish the centre of gravity ).
i even had to refuse a trial lesson one day because the guy was just too heavy. apart from the difficulty of physically getting him into the aircraft, i worked out i could carry no fuel at all with both of in the aircraft so it just was'nt on. he was pi$$ed...but all you can do in that situation is move him up to a bigger aircraft.
regarding your point that gravity wo'nt help....of course it will. surely you know the fuel drains are on the bottom ot the tank. open them and gravity does the rest.
as regards re-using that fuel...we never...ever..ever..did that. the engineering boys got that to wash things down. you can't dump it and you certainly should never put it back in the tank even if it has been drained into something spotless. fuel in JAAland and presumably where you are must only be supplied to aircraft from an approved fuel installation...which your jerrycan is not.!!
for flight testing we had to use PA28 or else in exceptional circumstances ( if weight permitted )we might agree as examiners to split the flight test into two.generally the candidate is told to ensure that as the flight test lasts about two hours to ensure that three hours fuel was on board ( though the latter part of the test is generally conducted at an airfield )...but is possible sometimes to do the navex first, refuel and then do the upper airwork. its far from ideal ( say in a situation where the navex if failed it can create complications )...but to facilitate sometimes one has to try to accomodate otherwise nothing gets done..
the fact you asked shows you are thinking...good for you..
fly safe..
the dean.
Join Date: Sep 2002
Location: Daventry UK
Posts: 487
Likes: 0
Received 0 Likes
on
0 Posts
At least some Pipers have the locking open type of fuel drains.
I became aware of this courtesy of the scrote who was eventually caught filling containers from aircraft at our field night after night. Not very messy at all.
(At least he turned the drains off again, unlike the different class of criminals who steal diesel from farms by smashing the valve with a hammer leaving the majority to run on the ground)
I became aware of this courtesy of the scrote who was eventually caught filling containers from aircraft at our field night after night. Not very messy at all.
(At least he turned the drains off again, unlike the different class of criminals who steal diesel from farms by smashing the valve with a hammer leaving the majority to run on the ground)
Join Date: Feb 2007
Location: Amsterdam
Posts: 4,598
Likes: 0
Received 0 Likes
on
0 Posts
At least some Pipers have the locking open type of fuel drains.
According to Jeremy Pratt in the Pilots Guide to the PA-28 Warrior (pg. 21) this has happened to the engine fuel strainer where people tried to drain with the fuel selector in the "OFF" position. So the dumping of fuel started only when people finished their walkaround, got into the cockpit and opened the fuel selector. No problem during runup and taxi, but the fuel would be totally drained just after take-off.
Join Date: Nov 2004
Location: uk
Posts: 1,224
Likes: 0
Received 0 Likes
on
0 Posts
rusty
for jockeys only
--------------------------------------------------------------------------------
According to the speadsheet, two moderately weighing people (200 lb each - moderatly fat bastards) would get about 50 min endurance. Which is not a lot.
That surprises me - as a training acft, operating within W & B must be a problem. Or am I overlooking something here?
I'd like to understand this - so will take ridicule if it leads to clarity.
--------------------------------------------------------------------------------
According to the speadsheet, two moderately weighing people (200 lb each - moderatly fat bastards) would get about 50 min endurance. Which is not a lot.
That surprises me - as a training acft, operating within W & B must be a problem. Or am I overlooking something here?
I'd like to understand this - so will take ridicule if it leads to clarity.
Join Date: Apr 2000
Location: 30 West
Age: 65
Posts: 926
Likes: 0
Received 0 Likes
on
0 Posts
There was, and probably still is a CAFU examiner who - should we say is rather - er - stout. She also alledgedly doesn't like any pilot with an external defuelling probe.
So.................
Legend has it that when said person presented for a CPL GFT, it was to be done in two sorties, due to the W & B being compromised.
Only in Great Britain
So.................
Legend has it that when said person presented for a CPL GFT, it was to be done in two sorties, due to the W & B being compromised.
Only in Great Britain
Re Backpacker's thread: a similar thing happened at E. Mids a few years back. As I understand it, a rather large lady tried unsuccessfully to get a fuel sample from the gascolator drain on a PA28 where the previous pilot had left the fuel cock in the off position. She pushed hard enough to bend the pipe inside the cowling and jam the mechanism just inside the hole (that the drain sticks out of) such that the drain was held open by the edge of the hole. Engine failed due to fuel starvation just after takeoff and a few runway end lights were taken out on the subsequent land on. Thank god for long runways.
