Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
737 Navigation Question On ADF/ HSI  
User currently offlineLufthansi From Germany, joined May 2002, 454 posts, RR: 2
Posted (5 years 8 months 1 week 5 days 9 hours ago) and read 7248 times:

Hi there!

I'm just doiung my (Maintenance Personel) Boeing 737CL Typerating.

Yesterday I had to write an exam about ATA 22 and ATA 34. I had a great success by having 31 right answers out of 33. One of the questions I answered wrong was about the ADF needle that can be shown on the EHSI (Electronic Horizontal Situation Indicator = lower display).

The question was: "What happens to the ADF needle on the EHSI when there is no reception on the selected ADF frequency"

a) it is not displayed
b) it is shown parked at the 09:00 o'clock position
c) it has no special position

Answer "b" was pointed out to be correct by two instructors. I've choosen "a" though...

I'm very sure that the needle is not displayed anymore.
It's clear that on the RDDMI the needle would be in the parked position ( 09:00 o'clock) since it cannot be removed on an analogue instrument.
But from my experience on the 737 of Lufthansa and my 737PIC I use to fly on my flightsim it is not shown if no frequency (within the range of reception) is selected.
[Lufthansa has no ADF selectable on the RDDMI (only 2 VOR needles). But on my sim the 737s have the RDDMI where each needle can be used vor VOR or ADF display.] And in each mode (FULL VOR/ILS; EXP VOR/ILS; etc) the ADF needle disappears if an ADF FREQ wihout reception is selected.
According to the instructor only on the 737NG and A320Fam. (talking about short range aircrafts here...) ADF needles are removed from the displayes when there is no reception.

Hence the course will be running for more than a week from now I don't have the time to jump into on of our Bobbies. So your experience is highly welcome!

WILCO 737 has a great image up here for this discussion. HSI is seen here and the RDDMI is pointing out 2 VOR/DME stations (no ADF selectors on LH 737s!).

http://www.airliners.net/photo/Lufthansa/Boeing-737-330/1406555/L/

Txs in advance!

Stephan

[Edited 2008-11-13 10:32:53]


Life starts at take-off!
3 replies: All unread, jump to last
 
User currently offlineChrisMUC From Germany, joined exactly 8 years ago today! , 66 posts, RR: 0
Reply 1, posted (5 years 8 months 1 week 4 days 16 hours ago) and read 7168 times:

Hi Stephan,

I had a quick look into my documents (OM-B, Chap. 12.11.30) to check (didn't want to rely on my memory) and you're right. On page 1 is stated that in case of ADF receiver failure the pointers are removed and on page 8, what is your question, that the pointer is only displayed if an ADF bearing is being received.
That's also what I remembered from flying the Bobby.

Good luck for the rest of your typerating,

Chris


User currently offlineLufthansi From Germany, joined May 2002, 454 posts, RR: 2
Reply 2, posted (5 years 8 months 1 week 4 days 13 hours ago) and read 7153 times:

Thank's a lot Chris!

Since we have the OM-B in our school too I'll show it to the instructor! Great to know that this is pointed out in the on-board-docs as well.

Stephan



Life starts at take-off!
User currently offlineAvt007 From Canada, joined Jul 2000, 2132 posts, RR: 5
Reply 3, posted (5 years 8 months 1 week 3 days 9 hours ago) and read 7065 times:

I would choose "a" as well, based on my knowledge of other EFIS aircraft. I'd be curious to know if "ADF failure" and "no reception" are the same thing, and handled the same by the system. I know of a case where DME failure, and DME weak/no signal are displayed differerntly.

Top Of Page
Forum Index

Reply To This Topic 737 Navigation Question On ADF/ HSI
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Question On The Accident Of BA B777, G-YMMM posted Sat Nov 1 2008 17:01:34 by Ajaaron
Question On UK Metars posted Wed Oct 29 2008 15:18:27 by RJdxer
Question On 777 Spoilers posted Sun May 18 2008 23:23:18 by Kaitak744
737-800 Question. posted Sun Apr 27 2008 12:57:27 by XAAPB
Question On Assigned Altitude posted Sat Apr 19 2008 22:36:28 by Jasp25
Question On Wing Design... posted Sun Mar 30 2008 01:15:40 by KhenleyDIA
Question On Aircraft Wing posted Tue Dec 25 2007 20:05:30 by Abrelosojos
Quick Question On The AT-CTI Program (ATC) posted Tue Dec 4 2007 15:55:06 by Boston92
737 Fuel Question posted Mon Nov 19 2007 12:51:41 by Captainsimon
Question On Aircraft Maintenance posted Sun Sep 23 2007 20:52:05 by Kaitak744

Sponsor Message:
Printer friendly format