Need help with an NDB question
Thread Starter
Join Date: Oct 2009
Location: ISRAEL
Posts: 31
Likes: 0
Received 0 Likes
on
0 Posts
Need help with an NDB question
Getting ready for a written test in a couple of days...
An NDB bears 279 degrees relative from an aircraft heading 209 degrees (C).
With deviation of -7 degrees and variation of 18E. What is the bearing of the aircraft from the NDB.
I tried adding the heading plus the RB and subtracting 360 =128 degrees
then subtracted the deviation which brings it to 121. But the answer is wrong.
I dont know why to use the variation as i dont need to change it to true unless I am wrong...
Any takers?
Thanks,
An NDB bears 279 degrees relative from an aircraft heading 209 degrees (C).
With deviation of -7 degrees and variation of 18E. What is the bearing of the aircraft from the NDB.
I tried adding the heading plus the RB and subtracting 360 =128 degrees
then subtracted the deviation which brings it to 121. But the answer is wrong.
I dont know why to use the variation as i dont need to change it to true unless I am wrong...
Any takers?
Thanks,
Join Date: May 2009
Location: melbourne
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
see if this helps...
luizmonteiro - Online Simulators - ADF Simulator
luizmonteiro - Online Simulators - ADF Simulator
Join Date: Apr 2007
Location: London, Berlin, Bucharest
Posts: 284
Likes: 0
Received 0 Likes
on
0 Posts
209-7= 202M being the direction your traveling.
therefore 81 degrees to the LEFT of the aircraft heading.
202-81= 121 TO the NDB
What is the bearing of the aircraft from the NDB
therefore 301 FROM the NDB
RTFQ!!!!
An NDB bears 279 degrees relative from an aircraft heading
therefore 81 degrees to the LEFT of the aircraft heading.
202-81= 121 TO the NDB
What is the bearing of the aircraft from the NDB
RTFQ!!!!
Join Date: Jun 2006
Location: Europe
Posts: 716
Likes: 0
Received 0 Likes
on
0 Posts
An NDB bears 279 degrees relative from an aircraft heading 209 degrees (C).
With deviation of -7 degrees and variation of 18E. What is the bearing of the aircraft from the NDB.
With deviation of -7 degrees and variation of 18E. What is the bearing of the aircraft from the NDB.
Relative bearing 279 + 202 = 481. Subtract 360 to get QDM 121.
Add 180 to get QDR = 301.
For plotting on a chart correct for variation at the aircraft (not at the NDB), ie line to plot = 301M+18E = 319T.
So 301M or 319T depending on what you want to use it for.
Last edited by bfisk; 6th Apr 2010 at 19:30.
Join Date: May 2004
Location: Neither Here Nor There
Posts: 1,121
Likes: 0
Received 0 Likes
on
0 Posts
The first point to note is that the question doesn't specify a True or Magnetic Bearing.
Nor does it specify whether the value of the Variation is applicable at the aircraft or at the NDB. Most questions of this nature tend to give two different values for Variation, one at the aircraft and one at the NDB, to test your knowledge of which one to apply. NDBs emit omni-directional signals, the bearing of which is measured at the aircraft on the ADF and therefore, if applicable, Variation is applied at the aircraft.
If the question was looking for a True Bearing from the NDB to the aircraft then the answer would be 319°T.
C = 209°C
D = -7°
M = 202°M
V = 18°E
T = 220°T
(T)HDG + RB = QUJ
220°T + 279° = 499° (-360°) = 139°T
The Reciprocal (QTE) from the NDB to the aircraft = 139°T + 180° = 319°T
If, on the other hand, it was looking for a Magnetic Bearing from the NDB to the aircraft then the answer would be 301°M.
C = 209°C
D = -7°
M = 202°M
(M)HDG + RB = QDM
202°M + 279° = 481° (-360°) = 121°M
The Reciprocal (QDR) from the NDB to the aircraft = 121°M + 180° = 301°M
We have two potentially correct answers:
301°M
319°T
Being a multiple choice exam, which one fits the given answer options?
As you've already given the 'correct' answer as 301°M it seems that Magnetic Variation is being ignored.
Nor does it specify whether the value of the Variation is applicable at the aircraft or at the NDB. Most questions of this nature tend to give two different values for Variation, one at the aircraft and one at the NDB, to test your knowledge of which one to apply. NDBs emit omni-directional signals, the bearing of which is measured at the aircraft on the ADF and therefore, if applicable, Variation is applied at the aircraft.
If the question was looking for a True Bearing from the NDB to the aircraft then the answer would be 319°T.
C = 209°C
D = -7°
M = 202°M
V = 18°E
T = 220°T
(T)HDG + RB = QUJ
220°T + 279° = 499° (-360°) = 139°T
The Reciprocal (QTE) from the NDB to the aircraft = 139°T + 180° = 319°T
If, on the other hand, it was looking for a Magnetic Bearing from the NDB to the aircraft then the answer would be 301°M.
C = 209°C
D = -7°
M = 202°M
(M)HDG + RB = QDM
202°M + 279° = 481° (-360°) = 121°M
The Reciprocal (QDR) from the NDB to the aircraft = 121°M + 180° = 301°M
We have two potentially correct answers:
301°M
319°T
Being a multiple choice exam, which one fits the given answer options?
As you've already given the 'correct' answer as 301°M it seems that Magnetic Variation is being ignored.
Thread Starter
Join Date: Oct 2009
Location: ISRAEL
Posts: 31
Likes: 0
Received 0 Likes
on
0 Posts
Hi Guys,
Been so busy studying for these 5 written exams. Have a few more days to go.
Thank you so much for the replies.
I was able to solve it per the "Read the question" remark. I think the answer was 301M.
I have another question but ill post it as a new thread.
Thanks again,
giladal
Been so busy studying for these 5 written exams. Have a few more days to go.
Thank you so much for the replies.
I was able to solve it per the "Read the question" remark. I think the answer was 301M.
I have another question but ill post it as a new thread.
Thanks again,
giladal