A passing thought on GPS nav....
Joined: Feb 2002
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From: Dublin
SFG,
Thank you for telling us your side of the story
It can be very easy to get overloaded when things go wrong, and you clearly took the right decisions....fly the airplane first, and ask for help early on.
Well done! I hope you enjoyed Gurnesey, and I hope your passenger has forgiven you
dp
edited for typo
Thank you for telling us your side of the story
It can be very easy to get overloaded when things go wrong, and you clearly took the right decisions....fly the airplane first, and ask for help early on.Well done! I hope you enjoyed Gurnesey, and I hope your passenger has forgiven you
dp
edited for typo
Last edited by dublinpilot; 10th September 2007 at 17:35.
Joined: Feb 2006
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From: Daventry
Turn back?
Very impressed with your candour in letting all know the build up to your 'moment'
As you said,the horizon was not too good,did you consider turning back?
Having read stuff about not trying to 'wing it' in bad vis/IMC, it may have been an option.I saw the 'appreciation of instruments' during my training as a way of getting yourself out of the brown stuff not as IMC Lite.
I recently had my first 'foreigner' EGBE to LFAT,but I chose to do it with the a/c owner (IR qualified) as with my low hours it helped to have someone to show me the ropes.The horizon was quite poor that day and I would probably have turned back if I had been alone.(maybe I am a wimp?).
I still plog/map/stopwatch but carry a GPS and if I am honest with myself I do use the GPS a lot to correct my track.
Happy landings
MM
As you said,the horizon was not too good,did you consider turning back?
Having read stuff about not trying to 'wing it' in bad vis/IMC, it may have been an option.I saw the 'appreciation of instruments' during my training as a way of getting yourself out of the brown stuff not as IMC Lite.
I recently had my first 'foreigner' EGBE to LFAT,but I chose to do it with the a/c owner (IR qualified) as with my low hours it helped to have someone to show me the ropes.The horizon was quite poor that day and I would probably have turned back if I had been alone.(maybe I am a wimp?).
I still plog/map/stopwatch but carry a GPS and if I am honest with myself I do use the GPS a lot to correct my track.
Happy landings
MM
Joined: Jun 2006
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From: Maders UK
Well done SFG,
It really makes me laugh when the person whose blood (or license) everyone is baying for pops up on the forum and puts their side of the story.
Most importantly SFG, you learned from this and will be a better pilot.
Personally I think you did a fine job, no harm done.
Judgemental, this forum? surely not!!
Now if I fessed up about some of the really dumb things I've done and lived to tell the tale...
SB
It really makes me laugh when the person whose blood (or license) everyone is baying for pops up on the forum and puts their side of the story.
Most importantly SFG, you learned from this and will be a better pilot.
Personally I think you did a fine job, no harm done.
Judgemental, this forum? surely not!!
Now if I fessed up about some of the really dumb things I've done and lived to tell the tale...
SB
Joined: May 2003
Posts: 664
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From: Yorkshire
SFG,
The majority of people you will find posting on Proon or elsewhere have never had to deal with a serious airborne problem. It is to your credit - especially with next to no experience - that you haven't either, because by concentrating on keeping the thing the right way up and asking for help early enough you prevented your problem from turning into a crisis, so - well done.
Things to do next ? I'd suggest getting some real instrument time and training in, but you've already thought of that. Obviously, next time you launch on something like this, you'll be making sure you know how all the toys work before you go, so that's covered too.
What's left ? Well, buying your pax an enormous bunch of flowers and charging them to the "instructor" who never showed you what less than ideal viz actually looks like springs to mind ... I don't know if most instructors do, but they ALL bloody well should at some point !
FF
The majority of people you will find posting on Proon or elsewhere have never had to deal with a serious airborne problem. It is to your credit - especially with next to no experience - that you haven't either, because by concentrating on keeping the thing the right way up and asking for help early enough you prevented your problem from turning into a crisis, so - well done.
Things to do next ? I'd suggest getting some real instrument time and training in, but you've already thought of that. Obviously, next time you launch on something like this, you'll be making sure you know how all the toys work before you go, so that's covered too.
What's left ? Well, buying your pax an enormous bunch of flowers and charging them to the "instructor" who never showed you what less than ideal viz actually looks like springs to mind ... I don't know if most instructors do, but they ALL bloody well should at some point !
FF
Joined: Jun 2003
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From: EuroGA.org
SFG - well done, you did exactly the right things, especially the way you dealt with the freaking out passenger (telling her to shut up) 
I would suggest you learn about VOR/DME nav though - it really is a piece of cake and once you now how you will never go back.
wobble2plank - I don't think you will get a 0.3nm fix with VOR/VOR navigation!! If you believe that, I suggest you learn about your aircraft systems before flying again (no kidding). A standard jet transport INS will do DME/DME updates (which, at a stretch will give you 0.3nm RNAV), and on the most modern aircraft will use GPS for the updates (because GPS is vastly more accurate, reliable and there is no issue with the navaid DOC) but in the unlikely case that it really does do VOR/VOR or even VOR/DME updating the error will more likely be "miles".
And to the rest of you GPS bashers.... I am on holiday in a very warm place (in Crete), a good 1500nm from the UK, and I navigated here entirely with GPS The last leg here was ~ 800nm. Never been lost, or even "uncertain of position" (the CAA authorised term) in 800hrs. Been here VFR too, 3 yrs ago, and amazingly had no problems then either. GPS/VOR/DME all the way. Never used visual nav since the day after my PPL skills test.
The stuff about the map being "100% reliable", well it is. The problem is that the pilot often ends up somewhere else on the "100% reliable" map, with the result that his position is not 100% reliable...
If coming back from le Touquet, and you have no idea where you are, do what countless WW2 pilots did when they got lost (which was exceedingly often) - fly sort of norff, and when you get to the coast, that is bound to be goode olde Engoland, and then fly along it until you see a place you recognise
Just don't do this when the Eastbourne air show is on
I would suggest you learn about VOR/DME nav though - it really is a piece of cake and once you now how you will never go back.wobble2plank - I don't think you will get a 0.3nm fix with VOR/VOR navigation!! If you believe that, I suggest you learn about your aircraft systems before flying again (no kidding). A standard jet transport INS will do DME/DME updates (which, at a stretch will give you 0.3nm RNAV), and on the most modern aircraft will use GPS for the updates (because GPS is vastly more accurate, reliable and there is no issue with the navaid DOC) but in the unlikely case that it really does do VOR/VOR or even VOR/DME updating the error will more likely be "miles".
And to the rest of you GPS bashers.... I am on holiday in a very warm place (in Crete), a good 1500nm from the UK, and I navigated here entirely with GPS
The last leg here was ~ 800nm. Never been lost, or even "uncertain of position" (the CAA authorised term) in 800hrs. Been here VFR too, 3 yrs ago, and amazingly had no problems then either. GPS/VOR/DME all the way. Never used visual nav since the day after my PPL skills test. The stuff about the map being "100% reliable", well it is. The problem is that the pilot often ends up somewhere else on the "100% reliable" map, with the result that his position is not 100% reliable...
If coming back from le Touquet, and you have no idea where you are, do what countless WW2 pilots did when they got lost (which was exceedingly often) - fly sort of norff, and when you get to the coast, that is bound to be goode olde Engoland, and then fly along it until you see a place you recognise
Just don't do this when the Eastbourne air show is on
Thread Starter
Joined: Jul 2005
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From: Ask OPS!
IO540,
Quite right, VOR/VOR will not give you 0.3 RNAV, hence the reason I posted twin independant GPS receivers BACKED up by DME/DME, VOR/DME, VOR/VOR as that is the FMGS redundancy. GPS Primary, followed by DME/DME fixing followed by DME/VOR followed by VOR/VOR. RNAV accuracy 0.3Nm downgraded dependant upon beacons/fixing mode available.
RTFQ.
Anything more before I fly?
Quite right, VOR/VOR will not give you 0.3 RNAV, hence the reason I posted twin independant GPS receivers BACKED up by DME/DME, VOR/DME, VOR/VOR as that is the FMGS redundancy. GPS Primary, followed by DME/DME fixing followed by DME/VOR followed by VOR/VOR. RNAV accuracy 0.3Nm downgraded dependant upon beacons/fixing mode available.
RTFQ.
Anything more before I fly?
Guest
Posts: n/a
The stuff about the map being "100% reliable", well it is. The problem is that the pilot often ends up somewhere else on the "100% reliable" map, with the result that his position is not 100% reliable...
Joined: May 2003
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From: Yorkshire
Just out of interest, does anyone know if there is a map showing the locations within the UK / Europe where you are always within range of, say, two DME/TACAN stations, and at what heights you must be for this to be the case ?
FF
FF
Thread Starter
Joined: Jul 2005
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From: Ask OPS!
FullyFlapped, there is a generic rule of thumb that you can use to get radio ranges.
I seem to remember it as being 1.44 x SqrRoot(Height of emmiter + Height of receiver)
It will give you a fairly good estimation of the receivable range.
e.g Emitter=8ft, Aircraft = 2000ft 1.44xSqrt(2008)= 65 Nm
Cheers
W2P
Sorry, forgot to add that this is the theoretical maximum range, not taking into account transmitter power, occlusion etc.
I seem to remember it as being 1.44 x SqrRoot(Height of emmiter + Height of receiver)
It will give you a fairly good estimation of the receivable range.
e.g Emitter=8ft, Aircraft = 2000ft 1.44xSqrt(2008)= 65 Nm
Cheers
W2P
Sorry, forgot to add that this is the theoretical maximum range, not taking into account transmitter power, occlusion etc.
Last edited by wobble2plank; 10th September 2007 at 15:01.
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From: EuroGA.org
Unfortunately these figures are rarely realised when flying at typical UK GA levels.
Under the LTMA i.e. at 2400ft or lower, the MAY VOR's DME is often not receivable from more than 15nm, when coming down from say CLN or DET.
This creates large gaps in coverage for low level flight in Class G.
50-80nm is possible at airway levels, say FL150-200.
I think that if one plotted the official navaid coverage of UK Class G, at say 2000ft, 3000ft, 4000ft, the resulting map would suprise some people.
Over the sea it's a lot better because one can (and would, for reasons connected with max time before ditching) fly at FL055+.
There are also different grades of DME. A DME for an instrument approach (called a TDME) has much less power. One would do well picking up one of those from >40nm no matter how high.
Finally, most VORs in France don't have a DME. I have noticed they have added a few recently but the main ones are still just a VOR.
As to flying in circles, this is a lack of training in radio nav. One always flies a heading, and in the event of a nav loss one continues to fly the heading. A "perfect pilot" will also be timing the leg, but frankly few people bother once they get into radio nav.
Under the LTMA i.e. at 2400ft or lower, the MAY VOR's DME is often not receivable from more than 15nm, when coming down from say CLN or DET.
This creates large gaps in coverage for low level flight in Class G.
50-80nm is possible at airway levels, say FL150-200.
I think that if one plotted the official navaid coverage of UK Class G, at say 2000ft, 3000ft, 4000ft, the resulting map would suprise some people.
Over the sea it's a lot better because one can (and would, for reasons connected with max time before ditching) fly at FL055+.
There are also different grades of DME. A DME for an instrument approach (called a TDME) has much less power. One would do well picking up one of those from >40nm no matter how high.
Finally, most VORs in France don't have a DME. I have noticed they have added a few recently but the main ones are still just a VOR.
As to flying in circles, this is a lack of training in radio nav. One always flies a heading, and in the event of a nav loss one continues to fly the heading. A "perfect pilot" will also be timing the leg, but frankly few people bother once they get into radio nav.
Joined: Jan 1999
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From: north of barlu
VOR/DME range
First one guy above posted that he could only get the SAM VOR at 60NM range at FL110.............. Get the system checked mate, your VOR unit of most likely the aircraft instalaton has a big problem, at that FL you should be getting the VOR at 100NM+
DME range is all about transmitter power and height at around the FL70 mark I can usualy get a DME station at 130-140NM provided it is not to near a major airport.
As you may know a DME station can only work 200 transmitters at a time and the weekest transmitters get pushed off the system. most modern airliners have five DME units 2 for use with the VOR/ILS and 3 to update the FMS/IRS and these usualy have a TX power in the order of 200W.
So you can so why those of you with a badly adjusted Narco DME are lucky to get DME at over 20 miles if you are near to a major airport as you are very lucky to get more than 40W TX power on a good day out of these units.
If you have a King KN64 you will get a lot better performance this unit will make 60W TX power at the very least, the KN62A and KN63 (same tx unit) will push out better than 100W so are at the top of the tree when it comes to DME range.
The King units are some of the very best bits of GA avionic kit in terms of reliability and usualy work for years without giving trouble, the more modern Narco units are not bad but need a lot more TLC if you want them to work well. If you have a Narco unit that is a bit suspect I can recomend the avionic shop at Stapleford as peope who understand these units an can get the best from the limited power avalable.
DME range is all about transmitter power and height at around the FL70 mark I can usualy get a DME station at 130-140NM provided it is not to near a major airport.
As you may know a DME station can only work 200 transmitters at a time and the weekest transmitters get pushed off the system. most modern airliners have five DME units 2 for use with the VOR/ILS and 3 to update the FMS/IRS and these usualy have a TX power in the order of 200W.
So you can so why those of you with a badly adjusted Narco DME are lucky to get DME at over 20 miles if you are near to a major airport as you are very lucky to get more than 40W TX power on a good day out of these units.
If you have a King KN64 you will get a lot better performance this unit will make 60W TX power at the very least, the KN62A and KN63 (same tx unit) will push out better than 100W so are at the top of the tree when it comes to DME range.
The King units are some of the very best bits of GA avionic kit in terms of reliability and usualy work for years without giving trouble, the more modern Narco units are not bad but need a lot more TLC if you want them to work well. If you have a Narco unit that is a bit suspect I can recomend the avionic shop at Stapleford as peope who understand these units an can get the best from the limited power avalable.
Joined: Sep 2003
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From: UK,Twighlight Zone
A&C, It was me that could only get SAM at 60nm the other. I can assure you there is nothing wrong with my GNS430 or MX170 or my King DME. Neither of my NAV/Com units were able to pick the signal up until around the 60-70nm mile mark. What you should get in theory as signal propagation is often very different to what you see in reality. I have enough time airways flying to know this as a fact.
I have often seen avionics struggle to get a number of different VOR's, some days it is better than others. With SAM the DME comes in a lot earlier than the VOR.
I have often seen avionics struggle to get a number of different VOR's, some days it is better than others. With SAM the DME comes in a lot earlier than the VOR.
Joined: Sep 2007
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From: England
So let me get this straight...
Before I was an idiot who should have his PPL revoked. Then I put forward my version of events and now I'm like some kind of sky god? Hmmmm.... So maybe there are two sides to every story after all.
Thanks for the kind words though. Lovely! Odd that the others who were so quick to judge have stayed rather more quiet.
Before I was an idiot who should have his PPL revoked. Then I put forward my version of events and now I'm like some kind of sky god? Hmmmm.... So maybe there are two sides to every story after all.
Thanks for the kind words though. Lovely! Odd that the others who were so quick to judge have stayed rather more quiet.
Thread Starter
Joined: Jul 2005
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From: Ask OPS!
I don't seem to recall any judgmental comments within my posts, I left that to the others who prefer to hang, draw and quarter then ask questions.
Often without reading the previous posts properly!
Have fun
W2P
Often without reading the previous posts properly!
Have fun
W2P
Joined: Jan 1999
Posts: 6,209
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From: north of barlu
bose-x
Range like that from a VOR recever would have me checking the antenna system from the box right back to the antenna I am guessing that you are using one antenna for both boxes via a diplexer.
I would expect the GNS430 to lock on before the MX170 as the GNS 430 is a more modern bit of kit, this is what leads me to think that the aircraft instalation is not up to muster, it is only likely to be a dirty or corroded connection but your comments about performance changing with the same VOR from day to day I would be minded to check for the ingress of moisture into the conection at the antenna end or corrosion affecting the antenna grounding.
At one time I was running two King VOR,s from the same antenna and the KX165A always locked on before the KX155 due to the 165A,s more modern receiver, having replaced the 155 with another 165A the lock on range is identical.
From memory a think that I have receved a good signal fron SAM well south of Cherbourg at FL 70 but I will have to check this as the range did not seem unusualy low at the time I did not take a lot of notice.
I would expect the GNS430 to lock on before the MX170 as the GNS 430 is a more modern bit of kit, this is what leads me to think that the aircraft instalation is not up to muster, it is only likely to be a dirty or corroded connection but your comments about performance changing with the same VOR from day to day I would be minded to check for the ingress of moisture into the conection at the antenna end or corrosion affecting the antenna grounding.
At one time I was running two King VOR,s from the same antenna and the KX165A always locked on before the KX155 due to the 165A,s more modern receiver, having replaced the 155 with another 165A the lock on range is identical.
From memory a think that I have receved a good signal fron SAM well south of Cherbourg at FL 70 but I will have to check this as the range did not seem unusualy low at the time I did not take a lot of notice.
Joined: May 2001
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From: UK
SFG
Well done, an interesting and candid account.
The only serious comment I made was that GPS rarely go wrong and it is usually ones own stupid fault if they do - like the antenna falling off.
It does however highlight why a hand held GPS will never be as reliable as a panel mount.
Bits fall off (imagine what can happen in a bit of turbulence), batteries run out, aerials are in the wrong place .. .. .. Plan for all of these things to happen.
We have discussed on this thread the wisdom of channel check outs before.
There be those that argue any half well trained PPL should be able to cross channel - others are more cautious. I have tended towards the second camp.
In spite of your PPL training it is "surprising" how disconcerting flying on instruments can be for the first time, and how common it is cross channel despite a reasonable forecast. It is unnerving the first time, degrades your capacity to deal with other issues, and until you have experienced the leans once you never quite appreciate what it is like.
SFG did well not to let the situation over well him.
Well done, an interesting and candid account.
The only serious comment I made was that GPS rarely go wrong and it is usually ones own stupid fault if they do - like the antenna falling off.
It does however highlight why a hand held GPS will never be as reliable as a panel mount.
Bits fall off (imagine what can happen in a bit of turbulence), batteries run out, aerials are in the wrong place .. .. .. Plan for all of these things to happen.
We have discussed on this thread the wisdom of channel check outs before.
There be those that argue any half well trained PPL should be able to cross channel - others are more cautious. I have tended towards the second camp.
In spite of your PPL training it is "surprising" how disconcerting flying on instruments can be for the first time, and how common it is cross channel despite a reasonable forecast. It is unnerving the first time, degrades your capacity to deal with other issues, and until you have experienced the leans once you never quite appreciate what it is like.
SFG did well not to let the situation over well him.