View Full Version : Fuel usage restrictions at B757
Rule Distance Zero
25th May 2004, 18:33
Bulletin for fuel usage restrictions is still valid but have any operator completed that technical update which allows all the fuel from center tank to be used or are everybody still flying with that extra 500kg?
blue belly
26th May 2004, 11:03
we still have the mandatory 500kg.... no mod done on our fleet yet...
...the latest Airworthiness Directive allows us to operate the 757 and 767 the same. In other words, we can now use the center tank fuel down to 500kg. However, there are other limitations associated with this. An example is if you have less than 2500kg center fuel at initial taxi, the center pumps must be off until reaching 10,000 feet.
Lucky Angel
26th May 2004, 16:37
Same problem with the 737NG,although the fuel in the centre tanks can be used even if pumps are off because of the scavenge pump.
Rule Distance Zero
26th May 2004, 21:03
What do you guys do if you have less than 2500 in the center as ramp fuel, do you just leave center pumps of and start them after 10000?
We did that nd had center pumps cavitating or smthg after selecting them on at cruise or climb. Press-light illuminated and flickered 10-20 min after selecting pumps on. So we started to select pumps on for a while before takeoff and switched them off at latest during before takeoff checks. That solved the problem.
>What do you guys do if you have less than 2500 in the center as ramp fuel, do you just leave center pumps of and start them after 10000?
Per the 757/767 AD, that's exactly correct.
>Press-light illuminated and flickered
One of the specifics written is that "A center tank fuel pump must be positioned OFF at the first indication of fuel pump low pressure at any time during flight. This includes low pressure indications that may occur as a result of pitch attitude changes."
For the 757/767, "approximately 500kg of fuel is required in the center tank to ensure the fuel pump inlets remain completely immersed when the pump switch is ON"
That is the intent.
As far as I'm aware, Boeing say you can take the centre tank fuel down to 400Kg now... It stops those repetitive 'Fuel Config' warnings....
Also, my company use 2,300Kg of centre tank fuel as the figure for turning (or not turning) on the pumps for engine start... Don't know if that's us or Boeing though.
:)
Rule Distance Zero
28th May 2004, 18:11
Those are the limits we are using also. Personally I start a clock when 500 appears and time 1 min which after turn the pumps OFF= No more "fuel config" but still 500 on gauge :E
As I mentioned earlier we got that PRESS-light problem but when we started to use pumps on ground, we got no more "press"-problems at level when selecting pumps back on.
:ok: