View Full Version : B737-300 Standby flight Instruments question

2nd Jul 2011, 13:50
During recent training in a B737-300 flight simulator, both engine driven generators were switched off to simulate loss of both engine driven gens prior to practice instrument flying on standby instruments. In this particular simulator, this leaves among other things, the standby ADI (with ILS needles), altimeter and ASI. Also the captains RMI and No 1 ADF. The Vol 2 shows which systems are not available.

It was noticed that despite the first officer's RMI being inoperative as published, the No. 1 ADF needle on that instrument worked normally but with relative bearings. If the captain's No. 1 ADF frequency was changed to bring up another NDB and it's needle pointed to the new station, the first officer's RMI needle also pointed in the relative direction.

My understanding was that no ADF information is available to the first officers defunct RMI. In other words, only the captain's No 1 ADF works normally.

Of course it may have been a simulator defect or even a company option.

Appreciate opinions.

2nd Jul 2011, 19:35
No, that's correct. The RMI card fails, but the needle is still powered. I've thrown out the manuals now, so can't give you a reference.

Capt Chambo
3rd Jul 2011, 02:13
From a very old Tech Manual that I have for the -300.
The list of serviceable equipment when on Battery power only, is at the end of the Electrical section along with some diagrams.

It hasn't formatted very well bit this is a list of the navigation equipment that will be available to you.

• ADF No. 1 • Captain’s RDMI • Captain’s HSI (non-EFIS airplanes) • First Officer’s RDMI (on some airplanes) • left IRS - AC • left & right IRS - DC (switched hot battery bus) • VHF NAV No. 1

My Tech. manual covers a number of a/c serial numbers, and diagrammatically it show that on some aeroplanes the ADF needle to be working, but the back card/RMI will not. I guess the answer to your original question is that it comes down to customer options.
The only other thing working on the F/Os side in this configuration is the clock, and on some models, the marker beacon lights!

3rd Jul 2011, 11:12
Thanks for the replies.