VOR Station Elevation in NPA
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VOR Station Elevation in NPA
Hi
737 FCOM 1 (Supplementary Procedures) mentions not to use AFDS VORLOC if the VOR station elevation is more than 5000ft. Can anyone explain me the reason and tells if there is a similar recommendation for other planes?
737 FCOM 1 (Supplementary Procedures) mentions not to use AFDS VORLOC if the VOR station elevation is more than 5000ft. Can anyone explain me the reason and tells if there is a similar recommendation for other planes?
Last edited by mmrassi; 3rd Dec 2013 at 01:17.
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Green Guard:
That would be correct with DME but not with VOR radials.
Along that line, DME slant range is disregarded in TERPs approach design because such errors are insignificant at approach altitudes.
strange, as the higher elevation of VOR station, the less error when ~20 NM or less
That would be correct with DME but not with VOR radials.
Along that line, DME slant range is disregarded in TERPs approach design because such errors are insignificant at approach altitudes.
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Yes, Denti, we do.
How else to follow a VOR? Do you go in heading sel.?! And follow up raw data?!
Lnav?! Then you risk map shift and input error at low altitude or terrain... So no, not allowed and not done in my outfit flying B737.
How else to follow a VOR? Do you go in heading sel.?! And follow up raw data?!
Lnav?! Then you risk map shift and input error at low altitude or terrain... So no, not allowed and not done in my outfit flying B737.
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mmrassi,
737 is 3 different aircrafts. Are you perhaps flying Classic? In my 737NG supplementary procedures, no such limitation is mentioned.
Captaintcas,
I think most airlines recommend LNAV for VOR tracking (in case of VOR approach, of course cross checked with raw data in the background). For departure, cruise and arrival, we rely on Require Navigation Performance vs. Actual Navigation Performance and associated caution messages (without raw data cross check). Most of the procedures and route structure require P-RNAV anyway (Europe). I have a feeling you are flying classic too?
Personally, if I track a VOR radial not part of a VOR approach, it will be with autopilot and FD off, for fun/practice (and not with AFDS VOC/LOC).
737 is 3 different aircrafts. Are you perhaps flying Classic? In my 737NG supplementary procedures, no such limitation is mentioned.
Captaintcas,
I think most airlines recommend LNAV for VOR tracking (in case of VOR approach, of course cross checked with raw data in the background). For departure, cruise and arrival, we rely on Require Navigation Performance vs. Actual Navigation Performance and associated caution messages (without raw data cross check). Most of the procedures and route structure require P-RNAV anyway (Europe). I have a feeling you are flying classic too?
Personally, if I track a VOR radial not part of a VOR approach, it will be with autopilot and FD off, for fun/practice (and not with AFDS VOC/LOC).
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VORLOC...wow, blast from the past!
In regards to the abv 5000' question, there is an increased radius of turn at higher altitudes that causes problems for the curve algorithm in the FD and autopilot software...
EDIT: Cosmo, where are you flying RNP DEP?
In regards to the abv 5000' question, there is an increased radius of turn at higher altitudes that causes problems for the curve algorithm in the FD and autopilot software...
EDIT: Cosmo, where are you flying RNP DEP?
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Thanks for all related and irelated answers.
I fly 735 which has GPS position update but we still see that there is a statement like this regarding use of VORLOC.
The last answer from our friend "underfire" was quite interesting and I appreciate if you give me more details regarding your idea.
I fly 735 which has GPS position update but we still see that there is a statement like this regarding use of VORLOC.
The last answer from our friend "underfire" was quite interesting and I appreciate if you give me more details regarding your idea.
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Despite everything said in the quotes, the system requires me to enter at least 10 charters to post a message... here by done (in excess).
underfire
Cosmo, where are you flying RNP DEP?
Cosmo, where are you flying RNP DEP?
cosmo kramer
Most of the procedures and route structure require P-RNAV anyway (Europe)
Most of the procedures and route structure require P-RNAV anyway (Europe)
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underfire
Cosmo, where are you flying RNP DEP?
Cosmo, where are you flying RNP DEP?
On a procedure or airway without an RNP alerting requirement:
Verify position.
...hence, you won't need to do a raw data check as long as the FMC is not alerting you to do so, and even if a VOR is part of your departure, as such you can fly it in LNAV and do not need to tune it and fly it in VOR/LOC....
....which was in response to Captaintcas:
How else to follow a VOR? Do you go in heading sel.?! And follow up raw data?!
Lnav?! Then you risk map shift and input error at low altitude or terrain
Lnav?! Then you risk map shift and input error at low altitude or terrain
For departure, cruise and arrival, we rely on Require Navigation Performance vs. Actual Navigation Performance and associated caution messages (without raw data cross check).
Last edited by cosmo kramer; 4th Dec 2013 at 18:24. Reason: edited to be less aggressive :-D