ATA 34-43 Weather Radar

767 with significant history of the left Weather Radar Transceiver failing.



Several parts had been replaced, but the problem persisted.

While doing a visual of system components.... we saw this



This is a section of waveguide, forward of the bulkhead that has a separation at the joint from solid to flexible.



The waveguide is basically a hollow tube (appox 1" x 3/8') that is used to transport microwave energy between the R/T and antenna. Aircraft with dual R/T's use a waveguide switch to route the transmit/receive energy to the selected system R/T.



What is interesting about this particular problem is that the signal loss through this opening should of been recognized by "both" R/T's. We found "one" problem, but did we fix "the" problem??? (Time will tell)

It can't be seen with the naked eye, but the antenna scan is not a smooth horizontal motion. It actually stops, sends/receives a signal, and then moves to the next position where it stops to completes another signal shot.

Some weather radar systems have a vertical trace also.

More advanced R/T's can predict windshear "before" the aircraft actually flies into one. EGPWS's tell you that you're "in" a windshear situation.

I found a Collins manual (really meant for pilots) that has quite of bit of information about weather radar systems.