Topic-icon UPS Birds (687-692), Left Outer Fuel Quantity

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1 year 3 months ago - 1 year 3 months ago #304 by Mark
An ongoing and never ending string of MEL's dealing with the left outer tank shutting off early during fueling.

To the best of my knowledge, there was a probe connection modification on the #11 probe done at the factory before delivery. (Was it done on both sides???? I don't know.) This modification left these set of aircraft with different total tank capacitance values between the wings. The left being lower.

Normal shut-off for a A300-600 outer tank is approximately 8.2K. On the UPS birds, the left outer shuts off around 7.9K.

This Is Normal!!!

From ERS 16-03790 the capacitance readings for the outer tanks on these aircraft have a split of just over 3pF. This split will double as the probe is covered in fuel. It is exactly this split (left being lower) that is causing all this confusion.

From page 512 of the ERS showing total tank, never wet capacitance, previously wet (unless from shop - almost all), and tolerance for the left and right wings and probes.


Outer Tank LH Wing

Total Probes 192.14 193.55 ± 2.35

Compensator (660QT) 26.65 26.85 ± 0.75
Probe 7 (632QT) 22.80 23.00 ± 0.72
Probe 8 (633QT) 40.00 40.26 ± 0.88
Probe 9 (634QT) 50.41 50.71 ± 0.97
Probe 10 (635QT) 33.58 33.83 ± 0.82
Probe 11 (636QT1) LH 25.25 25.45 ± 0.77
Probe 12 (637QT) 20.10 20.30 ± 0.70


Outer Tank RH Wing

Total Probes 195.70 197.16 ± 2.35

Compensator (660QT) 26.65 26.85 ± 0.75
Probe 7 (632QT) 22.80 23.00 ± 0.72
Probe 8 (633QT) 40.00 40.26 ± 0.88
Probe 9 (634QT) 50.41 50.71 ± 0.97
Probe 10 (635QT) 33.58 33.83 ± 0.82
Probe 11 (636QT2) RH 28.81 29.06 ± 0.77
Probe 12 (637QT) 20.10 20.30 ± 0.70

We've been balancing the wings (shutting off the right outer at 7.9K). The yoke actuators don't care as long as they see a balance.

We're talking 300 pounds here. 7.9 vs 8.2

Recognize the issue...... account for it...... and kick it out of town.
Last edit: 1 year 3 months ago by Mark.

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1 year 3 months ago #306 by joshua chute
Unfortunately, I had an assistant yoke actuator that was very concerned about it not showing full on the ecam the other day. After arguing about it I left the cockpit with a fresh write up and because this was last minute, a short delay. But I just reviewed the ERS. Thank you.

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1 year 3 months ago #307 by Mark
We had 691 through here yesterday. MEL on left outer. Cleared the item using AMM 28-42-00 and referenced the ERS (which is not a legal sign-off).
I can't post a PDF of the ERS as it is proprietary info.I'll send a copy via e-mail.

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