| Model |
Message |
Fuel
quantity condition (difference) |
Comments |
737-600/
-700/-800/
-900 |
IMBAL
(Discrete amber light on round-dial quantity indicator) |
1,000
lb (450 kg) or more between main tanks |
Illuminated
amber at difference >1,000 lb (450 kg). Displayed below main tank
with lower fuel quantity. Fuel quantity arc and digits on tank with
lower fuel quantity turn amber. Inhibited when airplane on ground.
Inhibited by fuel LOW indication when both indications exist. Displayed
until imbalance decreases to 200 lb (90 kg). |
| 747-400 |
FUEL IMBAL
1-4
(EICAS advisory message)
FUEL IMBAL
2-3
(EICAS advisory message)
|
3,000 lb
(1,360 kg) or more between main tanks 1 and 4
6,000 lb
(2,720 kg) or more between main tanks 2 and 3
|
Message no
longer displayed at difference <1,000 lb (450 kg).
Message no longer displayed at difference <1,000 lb (450 kg).
This condition has been observed to occur on long sectors when
fuel is being supplied from main tanks 2 and 3 to all engines.
|
| 757 |
FUEL
CONFIG
(EICAS advisory message) |
Approximately
2,000 lb (900 kg) or more between main tanks |
Both
center pumps switched off with usable fuel remaining in center tank
(approximately 1,000 lb [450 kg]) or left and right fuel tank quantities
differ by approximately 2,000 lb (900 kg). Inhibited by LOW FUEL
indication. |
| 767 |
FUEL
CONFIG
(EICAS advisory message/light) |
Approximately
2,000 lb (900 kg) or more between main tanks |
Both
center pumps switched off with usable fuel remaining in center tank
(approximately 1,000 lb [450 kg]) or left and right fuel tank quantities
differ by approximately 2,000 lb (900 kg). Inhibited by LOW FUEL
indication. |
| 777 |
FUEL
IMBALANCE (EICAS advisory message) |
Main
tank quantities differ by a predetermined amount (see comments) |
Fuel
imbalance will be set when difference between main tanks exceeds
allowable quantity at >30 sec. Allowable quantity is 4,000 lb (1,800
kg) when total main tank fuel is 45,000 lb (20,450 kg) or less (50,000
lb [22,725 kg] or less for 777-200 Increased Gross Weight [IGW]
and 777-300), with a linear reduction to 2,000 lb (900 kg) when
total main tank fuel is 111,000 lb (50,450 kg) (114,000 lb [51,800
kg] for 777-200 IGW and 777-300). Message signal will remain set
until imbalance decreases 200 lb (90 kg) below set quantity at >15
sec. |
| MD-11 |
LAT
FUEL UNBAL
(Alert message) |
4,000
lb (1,800 kg) or more between tanks 1 and 3 |
|
| MD-90 |
LAT
FUEL UNBAL
(Alert message) |
1,500
lb (675 kg) or more between right and left tanks |
Alert
is a customer option on some airplanes. |