Fuel draining

[galleypower]

Hello engineers,

I am wondering whether jet aircraft in commercial operation have to be regularly checked for fuel contamination (water) during ground checks. Is there any fuel drained on a regular basis? Cheers...

[Capot]

For what the fuel supplier in UK, and most other places must do, look no further than CAP 748 (http://www.caa.co.uk/docs/33/CAP748.PDF).

Aircraft operators will have their own procedures and regulatory requirements for checking for contamination and perhaps verifying the specification of fuel being delivered to them, probably varying in caution with the safety culture of the country of uplift.

[vs69]

Depends on the aircraft maintenance schedule as to when it is called for, could be on a daily check, or a weekly or each turnaround. Some types seem to be better at 'keeping' water than others!

[tested satis]

Or now that VS69 owns a house- once a day( great for the central heating!!):ok::ok::ok:

[clunckdriver]

In our fleet its before flight and after the aircraft has not moved for a while, thus no remixing takes place, it also explains why many of us drive Diesels!

[TURIN]

Daily Check requirement on Big Airways craft.

Others I have seen require water drains done if the aircraft is scheduled on ground for anywhere between 3 and 6 hrs. Depends on operator. Some only require it to be done when the aircraft is remaining over night at a domestic airport.
During winter ops some types require special procedures such as a long stay in a warm hangar to ensure the ice in tanks melts before sumping is carried out.

Hope this helps. :ok:

[mitzy69]

on old aircraft Boeing 707 lots of water could be drained out.
On modern a/c there are jet pumps with inlet pipes at the lowest point in the tank to suck the water up and put it at the inlet to the main booster fuel pumps and gets sent to engine. So there is not a little stagnant point where water collects any more to drain out. If aircraft is on the ground for a long time and the fuel settles the water will collect at the water drain point, so at a transit airport when the a/c lands and is refueled and departs with in 60 minutes it is a waste of time checking for water.
Seen a 45 gallon drum filled with water drains at African airports so the checks is still done at certain transit stops.

[Ladytech]

It takes about 4 hrs for water to settle out of fuel with the aircraft at rest.
Sumping after a refuel is useless. It needs to be done on a regular basis-
at least an "over-nite". I once saw an Airbus A300-600 with a 4 foot block of ice in a main tank opened for a repair on a B-check soon after a flight.

[Terry McCassey]

Ladytech - or put another way, water settles in Jet A1 at about 12 inches per hour. It therefore depends how much fuel there is on the aircraft to decide how long to let it settle.

[Bus429]

I once saw an Airbus A300-600 with a 4 foot block of ice in a main tank opened for a repair on a B-check soon after a flight.
Seen the same in the trim tank of an A310 in DXB.
Currently working with an AOC whose pilots have to drain fuel on pre-flight; they hate it because, due to the size of the aircraft (F406), they are getting covered in fuel.:ok:

[muduckace]

From my experience it is common for commercial carriers under a msg3 schedule to sump for water on a 7 day schedule.