thrust reverse isolation valve b 737 200
Joined: Jan 2004
Posts: 29
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From: Hopewell, Nova Scotia Canada
I have had that problem, turned out to be the nose gear was not completely up and locked due to snow. This may not be your issue but may have to do with main landing gear sensors in flight.
Joined: Apr 2004
Posts: 775
Likes: 2
From: near EDDF
chapter22, you have to define "open". 
The valve is de-energized in air. This mean that the valves shut off pressure to the reverser and connect the reverser hydraulic system to the system return line.
The valve is de-energized in air. This mean that the valves shut off pressure to the reverser and connect the reverser hydraulic system to the system return line.
Joined: Nov 2000
Posts: 15
Likes: 0
From: gatwick uk
The pressure switch is looking at the up stream hyd pressure to the thrust reverser. on the ground pressure would be expected at that point and via the air ground logic the light would be off.in the air the pressure switch should not see pressure if it does via the air ground logic the light would be on telling the crew that there was hyd pressure at the thrust reverser an unsafe situation with the possibility that if the flight crew were foolish enough to try and deploy the thrust rev in flight it may deploy. The schematic does not give the full story only the mechanical bits!!
Joined: Nov 2000
Posts: 15
Likes: 0
From: gatwick uk
On ground the valve is energized allowing hyd press to the thrust rev.in the air it is deenergised from memory I think this is correct only thing is with total electrical failure there would be no thrust rev which does not seem correct but can't check as do not have access to a -200 schematic! Unless the supply comes from the battery bus.
