Post by LOU on Jun 16th, 2011 at 3:53pm
A little more depth on the anti-ice system
This is the center of the F/E panel. There are 4 amber lights and a test switch and a test button. This panel is related to the wing anti-ice system.
In my last post I talked about the anti-ice panel on the pilot's overhead. On that panel, when you turn on the wing anti-ice you are routing bleed air from the engine through the strut into the aircraft in the aft stair part of the plane, then up the keel beam to the wing anti-ice duct which routes hot air to both wings to anti-ice the leading edge of the wing. Either or both engine one & three can supply wing anti-ice. In light icing conditions one engine would be enough to supply enough air to keep the wing clean.
This overheat panel in the center of the F/E's panel is there to monitor for hot air leaks. If there was a leak in the bleed air duct of the number engine around the strut area it could be large enough to light the amber warning light on this panel. The ENG 1 STRUT light would be on and the checklist would be used to try to isolate the leak by turning off the number one engine wing anti-ice valve. If the valve got stuck in the open position, then the thrust could be reduced to try to lower the bleed air temp. The next step, if that did not work would be to shut down the engine. You would still have the ability to anti-ice the wing from the number three engine. Check valves prevent the other engine's air from entering the supply duct of engine one.
In the middle of the three overheat lights there is one marked - LOWER AFT BODY. This light is there to protect the keel beam area in the event of a duct leak of the wing anti-ice system. Since this is a fairly large area, it may take a bit of time to heat up and it could have other manifestations such as an aft cargo overheat or very warm floor in the aft passenger cabin. Once the anti-ice valve is turned off, it could take a while for the area to cool enough for the light to go out.
The left side of the panel is the Wing Anti-Ice Auto Trip off system. If the wing anti-ice duct were to rupture in the pressurized area of the plane, high pressure bleed air would enter and pressurize the cabin. This system would sense the increase pressure and trip the wing anti-ice to off. If the break was large enough this could cause a loss of cabin pressure. Fun, hun? :-?
The parts of the wing that are anti-iced are - leading edge flaps (2 thru 5), fixed inboard wings above the leading edge flaps and the upper VHF antenna this is a mix of high and low pressure air. Anti-ice is more effective with the flaps up since the air has less area to keep hot. The hot air is dumped at the end of each wing.
Remember, the green lights on the anti-ice control panel are what Boeing calls valve agreement lights. If the switch is in the off position, and the light is green, then the valve is closed. same for open. The blue lights (fuel panel) are in-transit lights. These lights show when the valve is moving to the selected position.
Lou
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This is the center of the F/E panel. There are 4 amber lights and a test switch and a test button. This panel is related to the wing anti-ice system.
In my last post I talked about the anti-ice panel on the pilot's overhead. On that panel, when you turn on the wing anti-ice you are routing bleed air from the engine through the strut into the aircraft in the aft stair part of the plane, then up the keel beam to the wing anti-ice duct which routes hot air to both wings to anti-ice the leading edge of the wing. Either or both engine one & three can supply wing anti-ice. In light icing conditions one engine would be enough to supply enough air to keep the wing clean.
This overheat panel in the center of the F/E's panel is there to monitor for hot air leaks. If there was a leak in the bleed air duct of the number engine around the strut area it could be large enough to light the amber warning light on this panel. The ENG 1 STRUT light would be on and the checklist would be used to try to isolate the leak by turning off the number one engine wing anti-ice valve. If the valve got stuck in the open position, then the thrust could be reduced to try to lower the bleed air temp. The next step, if that did not work would be to shut down the engine. You would still have the ability to anti-ice the wing from the number three engine. Check valves prevent the other engine's air from entering the supply duct of engine one.
In the middle of the three overheat lights there is one marked - LOWER AFT BODY. This light is there to protect the keel beam area in the event of a duct leak of the wing anti-ice system. Since this is a fairly large area, it may take a bit of time to heat up and it could have other manifestations such as an aft cargo overheat or very warm floor in the aft passenger cabin. Once the anti-ice valve is turned off, it could take a while for the area to cool enough for the light to go out.
The left side of the panel is the Wing Anti-Ice Auto Trip off system. If the wing anti-ice duct were to rupture in the pressurized area of the plane, high pressure bleed air would enter and pressurize the cabin. This system would sense the increase pressure and trip the wing anti-ice to off. If the break was large enough this could cause a loss of cabin pressure. Fun, hun? :-?
The parts of the wing that are anti-iced are - leading edge flaps (2 thru 5), fixed inboard wings above the leading edge flaps and the upper VHF antenna this is a mix of high and low pressure air. Anti-ice is more effective with the flaps up since the air has less area to keep hot. The hot air is dumped at the end of each wing.
Remember, the green lights on the anti-ice control panel are what Boeing calls valve agreement lights. If the switch is in the off position, and the light is green, then the valve is closed. same for open. The blue lights (fuel panel) are in-transit lights. These lights show when the valve is moving to the selected position.
Lou
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