Although they are not considered crew alerts, the following status messages indicate system malfunctions that preclude dispatch. If any of these messages appear after dispatch when outbound from the UK, consider contacting MAINTROL.
| Message | Meaning |
|---|---|
| AIR/GND DISAGREE | The two air/ground logic systems cannot agree whether or not the main gear trucks are tilted |
| BODY DUCT LEAK | Duct leak between APU and isolation valve. |
| CAPT INST XFER | Captains Flight Instrument Transfer Bus transferred with Left Main AC Bus powered. |
| CAPT STBY INV | Captain's Standby Inverter self-detected fault. |
| ELEV ASYM | Elevator Asymmetry protection system fault. |
| ELEV FEEL | Elevator feel system detects fault (on -300 aircraft this is an advisory message) |
| ELEV L/C/R HYD PRESS | L/C/R elevator hydraulic system pressure reducer valve senses high or low pressure. |
| EQPT SMOKE TEST | Forward equipment smoke detection system failed automatic test. |
| FO INST XFER | First Officers Flight Instrument Transfer Bus transferred with Right Main AC Bus powered. |
| L/C/R HYD SYS MAINT | L/C/R hydraulic system pressure low with both engines running. |
| L/R ENG LP PUMP | Low pressure detected downstream of L/R engine LP fuel pump with engine running. |
| L/R ENG SPEED CARD | L/R engine N3 speed sensing relay fault |
| L/R SURGE CONT | L/R engine Bleed Valve Control Unit detected dispatch-critical failure of the bleed valve control system with engine running. |
| L/R OIL FILTER | L/R engine oil filter differential pressure approaches bypass. |
| L/R ENG FUEL FILT | Differential pressure across L/R engine fuel filter approaches bypass. |
| MAIN BAT CHGR | Main Battery Charger failure. |
| NOSE A/G DISAGREE | The two air/ground logic systems cannot agree whether or not the nose gear oleo is compressed |
| RAT | Ram Air Turbine system inhibited from deployment or deployed on the ground. |
| STBY INVERTER | Standby Inverter voltage output outside normal limits with Main Battery switch ON. |
| T/R UNIT | L/R Transformer-Rectifier Unit failure (DC Bus Tie Closed) |
Boeing Dispatch Deviation Guide