ADF v. GPS [Archive] - PPRuNe Forums

wsmempson

11th Feb 2012, 11:09

You and I get the point, Peter. The problem is that there is still a generation of ex-RAF navigators/pilots/air-traficers out there, who are now embedded in the upper echelons of the CAA and EASA rule-making departments who still refer to extremely sophisticated panel mounted GPS panel mounted devices as "GPS wonder-boxes" as if they were the work of beelzebub, and no real substitute for non-precision NDB approaches flown with a stopwatch and the aid of a navigator.

Although i regularly fly the NDB procedure at my home base of Oxford, and am happy to do so as the surrounding scenary is sufficiently low not to worry me, the NDB 20 approach at Shoreham has the double gotcha of proximaty to the sea (with all the well known problems for NDB's) and high hills which scares the bejesus out of me.

Until the old guard at the CAA finally retire to tend their dahlia's, we're stuck with these ludicrous anachronisms.

thing

11th Feb 2012, 11:16

Until the old guard at the CAA finally retire to tend their dahlia's, we're stuck with these ludicrous anachronisms.

I agree, but the approaches are there and you may have to use them. I've recently done the IMCR and was bleating about NDB approaches to my instructor, he reckons in ten years it will be mandatory to use GPS.

achimha

11th Feb 2012, 12:12

I know everybody flies NDB approaches using the GPS. Is that actually legal?

peterh337

11th Feb 2012, 12:14

My point, not well made, is that you can fly a published NDB procedure using a GPS.

So I have nothing against NDB procedures, or VOR procedures for that matter :)

I don't see NDBs going away either, for many years. They are OK as locators and are a lot cheaper to keep going than VORs.

Whopity, I know what you are getting at but I am 100% sure one would hit terrain if one flew to EGKA on a track sufficiently different from the 20 inbound at the MDH :) I don't think that merely following the DME-based stepdowns would protect the obstacle clearance.

Is that actually legal?

100% legal for private ops. Only on AOC ops you have a procedure manual which specifies how things should be done. In private ops, the regs mandate equipment to be carried, not equipment to be used.

Whopity

11th Feb 2012, 13:39

ex-RAF navigators/pilots/air-traficers out there, who are now embedded in the upper echelons of the CAA and EASA rule-making departmentsSadly you are as out of touch as those using an astrodome; the Rule Making process is now the province of Clerks and Lawyers who know the square root of nothing but at least they can't be accused of being biased, that would require knowledge!

My point, not well made, is that you can fly a published NDB procedure using a GPS.Peter, I think you mean that you can fly a pattern resembling an NDB procedure using a GPS. You can also do it using all sorts of other equipment but without the NDB, its not an NDB procedure.

peterh337

11th Feb 2012, 16:03

There are two approaches (no pun intended) to this.

One is to fly the full published procedure, but using GPS navigation. That is usually what I do, and it is what ATC expect (because they don't know, nor do they care, how you actually navigate around the procedure). I would call that "flying the NDB procedure".

The other is to fly some form of abbreviated procedure, whereby one just intercepts the inbound track like it was a localiser. That is obviously stupid if you told ATC that you are flying the procedure. I would also bet that obstacle clearance would not be assured in all possible cases worldwide. But it is tempting because the reason for the "classical" IFR business of tracking to the beacon and then tracking outbound is because in the goode olde days there was no straightforward way to self intercept an inbound track. GPS makes it trivial.

Gertrude the Wombat

11th Feb 2012, 17:33

The other is to fly some form of abbreviated procedure, whereby one just intercepts the inbound track like it was a localiser.
So wot about using GPS to position for the ILS then, in the absence of radar vectors? The one place I've tried it ATC have been perfectly happy with a self-positioned ILS approach, but they knew perfectly well it was for practice and I was actually in VMC. Are there any rules about this?

mad_jock

11th Feb 2012, 17:38

nope no rules.

Just ask for 4/6/8 mile center fix and if able the controllers will let you sort yourself out.

proudprivate

11th Feb 2012, 18:21

My point, not well made, is that you can fly a published NDB procedure using a GPS.

Yes, if it is IFR En Route and Terminal or better (i.e. including Approach) as per AIM 1-1-19, then you would be daft not to use it instead of a horrible ADF.

If it is VFR panel mount or hand held, it is a great addition to situational awareness while flying the needle as a primary indication.

What struck me in your comment was your point that the NDB approach can be flown within tolerance (with the error on the wrong side) and still hit terrain. Is the Shoreham NDB approach procedure ill-conceived ?

The other is to fly some form of abbreviated procedure, whereby one just intercepts the inbound track like it was a localiser.

I know at least a couple of places where that would be a really bad idea, for precisely the reasons you mentioned.

nope no rules

...apart from having an panel mounted approved GPS IFR installation. They would only do that if your flight plan indicates /G.

peterh337

11th Feb 2012, 18:29

So wot about using GPS to position for the ILS then, in the absence of radar vectors?With a radar equipped airport, there cannot be an issue (if you told them so, etc).

With a non radar airport, the default ATC expectation will be that you will track to the beacon, perhaps go around the hold, fly outbound, and intercept the LOC. If you asked for a direct intercept, it should be OK of course, but IME they are a lot less likely to agree to it. Lydd is a classic case of this, with its silly "half-hour" DME arc. I have on occassions asked for a direct intercept when booking the ILS with a phone call but when I got there they wouldn't entertain it.

I am no expert on procedure design but there has to be a difference between a procedural NDB/VOR/etc IAP and a radar-vectorable ILS IAP. The former could potentially have its obstacle clearance designed to be assured only when you fly the full published version. The latter must be designed so that you are safe within the entire radar vectoring area, and if you do a self intercept and obey the limits of the radar vectoring area (which is published) then you should be OK. Obviously at Lydd, Manston, Bournemouth there is nothing to hit at the ILS platform for many miles around :) but in principle this is dodgy e.g. you must not descend to the ILS platform until firstly inside the MSA (shown on the 25nm rad circle on the plate) and then secondly inside the radar vectoring area, but your GPS is unlikely to depict the boundary of the latter. That is why, in a non radar environment, it seems obvious that you should be flying the full published procedure even to a radar vectorable ILS, unless the ILS platform is above the SSA.

If it is VFR panel mount or hand held, it is a great addition to situational awareness while flying the needle as a primary indication.A lot of people say that but no law actually says that, however.

What struck me in your comment was your point that the NDB approach can be flown within tolerance (with the error on the wrong side) and still hit terrain.

I think not. I think that the NDB procedure designers do actually know just how absolutely crappy they are (even if their paymasters never admit it) and they put in big margins. At Shoreham, provided you obey the DME stepdowns, you should be OK with a good 30 degree departure from the inbound track :)

mad_jock

11th Feb 2012, 18:55

apart from having an panel mounted approved GPS IFR installation. They would only do that if your flight plan indicates /G

you don't need that either.

I have done a few with just using the NDB on the field and the 1 in 60 rule and the ILS DME

If I was the wrong side for a straight in I would ask for self position for the ILS.

The ATCO has no clue at all about whats on the equipment list on your flight plan.

Once your taking to a controller you can ask for what you like and its up to them to say yes or no. As a none qualified VFR pilot you can request an ILS and they may give it to you. But its up to you to remain legal which is more than likely impossible if you are solo.

proudprivate

11th Feb 2012, 19:43

you don't need that either. I have done a few with just using the NDB on the field and the 1 in 60 rule and the ILS DME

Ok you're flying into a hypothetical airport with an NDB/DME approach. Airport elevation is 500 MSL. You have an NDB Needle and an ILS DME.

You're at 3000 MSL, flying solo at 135 KTS IAS, a heading of 360, the wind likely to be strong (about 30 KTS) and from 270-ish. Its full IMC, with a 1400ft ovc ceiling.

You've just past the last en route waypoint "BLIMY". Your DME indicates 15 NM to the NDB, your ADF needle points 40° to the left.

Your little chat with ATC results in them asking you to position yourself at the 6 NM center fix.

What heading do you turn to, using your 1 in 60 rule ?

[My point being that I would question mental arithmetic being good airmanship in this situation. And if it is VMC, then you don't need to position on some center fix, you could fly directly to the airport.]

But its up to you to remain legal

hence my point to have a panel mounted approved GPS to do this.

@peterh :

If it is VFR panel mount or hand held, it is a great addition to situational awareness while flying the needle as a primary indication.
A lot of people say that but no law actually says that, however.

Well, if you are flying N-reg, then AIM 1-1-9 tells not to use handhelds or VFR only panel mounts for IFR navigation. The reason the FAA puts forward is the lack of guaranteed updates and/or lack of RAIM. I don't know the actual law that describes the table. The operations law bit is then regulated by §91.175, 91.181 and the catchall (forgot which one) about having to have the necessary navigational equipment to conduct the flight.

peterh337

11th Feb 2012, 20:57

I'd say 2 things:

AIM is not law. The FARs are the law.

The equipment to conduct the flight is required to be carried. No law says it must be used to actually perform the navigation.

FWIW, the above is a regular topic which has been done to death on US pilot forums over more years than I have been flying.

I wouldn't say that a handheld GPS is particularly necessarily good for this kind of thing, partly because most of them don't have an OBS mode.

mad_jock

11th Feb 2012, 21:05

Just because you are talent limited doesn't mean the rest of us are.

I have over 8000 instrument approaches how may do you have?

There is no legal requirement for G reg aircraft to have a panel mounted GPS to do what I am suggesting.

There are actually a number of ways you could do it. One of which is to fly a 7 DME arc (which is also a piece of piss). Turn in to establish with 5 deg to turn in to runway heading.

Or you could point it at the field and then with 7 miles to run take a 45deg wind adjusted heading then turn to intercept at 6 miles.

The actual point you should be asking is if I am above MSA when I am doing this. If I am it really doesn't matter what I do if so cleared. If I am under MSA I really am quite silly to attempt to do it.

If you give me the runway QDM I can give you the heading if you really want.

But to be honest we need to do this calc anyway so that we can work out our min distance to run to make sure we arn't going to get hot and high.

We are also working out our decent profile as well so we get continuos decent profile all at the same time. Some have boxes of tricks to do it, some of us don't have that so do it in our heads. The reason why I sometimes do a in the head job is because its a pain in the arse getting the centerfix into the gps. It really isn't a special ability of mine, an old boy taught me how to do it years ago. And I think he got taught how to do it when he was flying Shackletons.

proudprivate

11th Feb 2012, 23:55

Just because you are talent limited doesn't mean the rest of us are.

polite and considerate, in your usual way. QDM would have been 270, btw. Everyone can calculate the heading, it is just that doing it in your head while flying IMC and doing an instrument scan would be tricky.

Neither the 7 DME arc, nor flying directly to 7 DME point 40° would have you complying with an ATC clearance "Direct 6NM center Fix".

I have over 8000 instrument approaches how ma[n]y do you have?

More than you think and more than enough to fly a 7 DME arc or an NDB procedure. Not enough to fly direct to a 6 DME center fix using the 1950s equipment of this hypothetical exercise. I'm of course handicapped by my limited in-flight mental arithmetic talents. Which is why I'm asking the question: I'm an avid student, eager to pick up nuggets of wisdom as they appear.

I agree of course that if you are above MSA within the MSA radius, a CFIT is excluded and a collision hazard is virtually non-existent as ATC would not agree with a direct 6 DME center fix if anyone else was likely to be in the neighbourhood of your flight path.

This whole discussion got out of hand when you said "nope, no rules". Which, after reading through the AIM and the online US CFR, might actually be true, because all this nonsense about panel mounted GPS systems only applies to US airspace (see below).

@ Peterh : I couldn't find the relevant references you were referring to on the US forums.

Interestingly enough: Part § 61.65 Instrument rating requirements tells us that we have to study the AIM as regards operations under IFR, but nowhere does it say that you have to abide by them after passing your IR check ride :)

However, the AIM publication itself says :
"This manual contains the fundamentals required in order to fly in the United States NAS. It also contains items of interest to pilots concerning health and medical facts, factors affecting flight safety, a pilot/controller glossary of terms used in the ATC System, and information on safety, accident, and hazard reporting"

but Part 91 doesn't mention mention either the word AIM or the word GPS :ugh:

Then again there must be something in the statutes of the FAA that allows them to enforce 1-1-19, because the first paragraph of chapter 1 reads:
Various types of air navigation aids are in use
today, each serving a special purpose. These aids have
varied owners and operators, namely: the Federal
Aviation Administration (FAA), the military services, private organizations, individual states and
foreign governments. The FAA has the statutory
authority to establish, operate, maintain air navigation facilities and to prescribe standards for the
operation of any of these aids which are used for
instrument flight in federally controlled airspace.

We are not talking about Federally Controlled Airspace in the UK, so this is irrelevant for a Part 91 operation in the UK.

Big Pistons Forever

12th Feb 2012, 03:09

The last time I flew a non training NDB approach in actual IMC without following the GPS generated course to the MAP either as a raw data number, OBS selected track or HSI trackbar indication, was 1994. The NDB needle was only monitored to see that it pointed in more or less the right direction. The constant was unlike pure NDB approaches the aircraft track was always aligned with the runway centerline when I broke out. :ok:

BEagle

12th Feb 2012, 10:12

I often wonder what the view of the CAA certification folk would be in response to an avionics company who knocked on their door to announce:

"We've got 2 systems for you to think about today. One uses medium wave signals and is liable to co-channel interference (particularly at night), passing Cbs, coastal refraction and other errors. It doesn't give any information to the pilot except its identification using slow more code. To use it, the aeroplane will need an expensive radio receiver, a cumbersome antenna system and a cockpit display. Unless the aircraft also has a decent gyrocompass, the pilot then has to interpret the reading and compare it against a suction driven direction indicator.

The other system uses a constellation of transmitters with considerable redundancy and a ground agency constantly monitors the system's health. It requires a relatively simple aircraft installation and antenna; software can provide the pilot with precise position/height/groundspeed and location on a moving map, the pilot can construct way points of choice and fly safe, accurate routes anywhere in the world. It can even be an entirely hand held device which the pilot can also use when driving to and from the aerodrome or when out and about on foot."

Would the CAA then say "Yes, but we think that the medium wave, interference-ridden system with its expensive airborne installation is OK for descending to the aerodrome on an instrument approach, but the modern, constantly-monitored software-enhanced system is, we feel, far too risky to use for such a purpose".

:hmm:

There probably are some "It's not acceptable without an astrolabe, quadrant staff and lodestone" crusties of the RIN or wherever who still chunter about the 'Tool of Satan' which has made navigation so much easier nowadays..:bored: They should certainly be ignored!!

And yes, My Beautiful Garmin is indeed a wonderful box of tricks. The best thing since offset TACAN, in fact. What goes in in its chips and circuits is utter magic involving the mysteries of doppler shift and high speed simultaneous equations with allowance for ephemeris and ionospheric corrections - or somesuch :\ . Not that anyone should ever really need to know 'how' it works, just accept that it 'does' work. And very well indeed! I bought 4 panel mounted systems for my old club's aircraft and the only failure we ever had was when one antenna (which hadn't been installed properly) allowed water ingress into the cable. Whereas we had constant problems with the King ADFs....

Checking my Garmin on the way home yesterday, I saw that it was receiving EGNOS signals from Inmarsat (ID 33) and Artemis (ID 37) at times - but the system accuracy didn't seem to be any better than when it wasn't receiving EGNOS. But 5 metre accuracy in a car doing 70 mph is still pretty amazing to me :ok: !!

mad_jock

12th Feb 2012, 10:16

More than you think and more than enough to fly a 7 DME arc or an NDB procedure. Not enough to fly direct to a 6 DME center fix using the 1950s equipment of this hypothetical exercise. I'm of course handicapped by my limited in-flight mental arithmetic talents. Which is why I'm asking the question: I'm an avid student, eager to pick up nuggets of wisdom as they appear.'

Have a mental model of where you are in relation to the airfield at all times as your capacity increases this model also includes traffic that you can hear as well. This will help because you will the know when to expect the next vector which can help you plan when you slowdown and when to configure (I know maybe not much a consideration when your doing 130knts but it is when your doing 230-250knts). So from my mental model I would be thinking 300 but would expect it to be tight. The actual point your aiming for is 1-1.5 miles out from the center fix to the north. Then see what the needles are telling me and adjust to get to 7 miles out with 10 degs on the NDB to the runway QDM.

Arith method
15miles out is a quarter of 60 so each degree is quarter of a mile so 40deg to the left currently your 10 miles laterially to the right of the airflield you want another 6 miles ontop of that which is another 24 round it up to 25 to give a bit of space so add that to your 40 you get 65 round. As for wind drift you can start with 5 And adjust. Once you get nearer then adjust keeping in mind you turn in distance which if you haven't been told is move two decimal places on your gound speed and half it to give your distance (same as joining an arc) per 90 degs but you need to adjust that for the wind always with a turning into a tail wind add a bit of extra. So ground speed of 150 knts is 1.5/2 = .75

20 miles out is a third of a mile to a degree
15 miles is a quarter
12 miles is a fith
10 miles is a sixth (or add 10% on to the 12 mile or double the twenty)

So arith method 360-65-5 = 290

So really there isn't that much arith involved.

60/15 = 4degs per mile
40/4 = 10 miles
6*4 = 24
40+25= 65
360-65-5 = 290 I would expect that to have plenty of room.

And because I haven't done a mental sensible check I would have done in the cockpit looking at the instruments I have turned the wrong way and set up for the wrong end and coming in from the north :D

Its alot easier with your beam bar set up on runway direction and referencing it to the ADF and aslo in the air you have your pilot head on and not running an abstract problem.

Anyway i will leave it as you can see the logic with the arith and also spot where i went wrong.

And for the proper question what I would do is turn 20 to the left and then when I was 5 deg off runway QDM turn for a 30deg intercept ad that will get you onto it at about 6 miles. Your about 10 miles away from the center line and you want to chop 4 miles off from the 11 that you would have if you had continued straight ahead. Which is about 25degs but you don't want a 90deg intercept. So knock 5 off and the wind will help you not get tight.

And I also do this in an aircraft designed by Handle Page which Beagle hates with a passion.

BEagle

13th Feb 2012, 07:38

Yes, m_j, it might originally have been designed by Sir Fred, but the BWoS version you fly (I presume the J41) is a vastly different beast to the wretched T Mk 1 which I had the misfortune to fly!

Are yours GPS-equipped yet?

mad_jock

13th Feb 2012, 08:40

J31/J32 and J41.

J31/J32 G reg all have GPS, EGPWS and TCAS now as well. What flavour of GPS is dependent on what was fitted there are about 4 different common models that have been used to comply with it.

The most common installation is this

http://www.trimble.com/products/pdf/2101ap.pdf

From the ex mil types the engine change to Garretts made a huge improvement. But its still a bitch to land.

Agreed the J41 is a different beastie altogether.

flybymike

13th Feb 2012, 12:32

Idle curiosity MJ, What makes it particularly bastard like to land?

gasax

13th Feb 2012, 12:42

I'd be interested to know as well - given that is probably about a dozen flights as SLF I've only had one landing which could be described as less than 'bone rattling' - but to be fair I did congratulate the crew!

BEagle

13th Feb 2012, 12:56

Personally I considered that the Jetstream T Mk 1 had the worst control harmony of anything I'd ever flown. It seemed heavy but sensitive in pitch, light and unresponsive in roll. Another problem was that the airflow from relatively large diameter propellers over a small, high aspect wing would cause any asymmetric prop blade angles to generate roll.

Thus on landing you would work hard in gusty conditions to keep the things wings level, whilst making small pitch inputs. Then, if you brought the power levers back to idle just before the flare, it would lurch out of the sky as all the lift fairies buggered off, leading to an imprecise impact with terra firma. I learned to keep some power on through the flare to make things slightly more predictable - no problem on a V-bomber runway, but not a generally accepted technique!

We had to fly the things 'single pilot' - with just nagging and moaning from the QFI in the other seat. His only 'multi-pilot' activity would be to raise the landing gear after a touch-and-go - the PIC did radio, navigation and poled the brute. We rarely used the autopilot as it was horribly unreliable and could generate rapid short period pitch cycling....

The Astazou starting sequence was hilarious; a starting brief followed by lots of fingers pointing at various light and gauges, then the necessary switchery needed whilst the abortionate French engines wound up. There was one brief which always amused me "Co-pilot, you are to restrain the flight fine pitch mechanical lock lever!". Restrain it lest it rise up and smite thee, or what? It was more pleasant to fly on one engine than on two, because the performance wasn't much affected at the heights we used and it only made half the noise!

We were supposed to taxy the pig using nosewheel steering which was incredibly stiff and hard to move on cold days. Even though it taxyed very well using differential power and brake, thanks to the wide track undercarriage, that wasn't allowed by the CFS gurus.

As for systems, I recall that it had about as many different methods for producing electricity as could be imagined - short of the Wimshurst Machine and Van de Graaff generator. Batteries, starter generators, alternators, inverters.....

Awful sodding thing. As I commented to one QFI, "If it really is this hard to fly from Doncaster to Nottingham at little more than 2 miles per minute, I'd go by train!"

Oh and by the way, GPS is better than ADF.

mad_jock

13th Feb 2012, 13:13

There are a few theorys out there some of them ancedotal and others in the realls of engineering design.

Rumours out there.

1. When they produced the first 3 pre production machines they had a different landing gear design and were quite nice to land. The RAF took one look at it and said we would prefer the extra traffic load . And they replaced them with straight legged with about 4" of travel. Then the fun began.

2. The wing on full flap has a nonlinear responce (I didn't have clue either what that meant) but apparently the air dams up behind the flaps at high alphas in ground effect and then something technical happens and you suddenly loose quite a bit of lift. This might have a grain of truth because if you float its going to suddenly drop you.

3. Its a JSP something or other design spec which is a military spec not a civi one (I think thats crap because other transport military machines don't seem to have the same issues)

4. Because of only having 1 wheel on each main leg the plane gets pulled down to the ground when they touch the runway and the friction spins the wheel up. This in my experence has some merit as a smooth landing is more likely with about 10 knts of crosswind, the runway deiced, snow packed or wet. No wind dry day I have thumped in some peachers which you wouldn't be able to spot the differnce in what I am doing to when I have done a greaser.

In practise experence counts alot but even then some pilots out there never really get a consistant pleasant landing and even what we would count as pleasant is somewhat firm.

When you first start flying them you get alot of crunchers and then they get better then worse again. Some folk get the nack and get predominately normal landings but even then occassionally she will bite and dump you on the deck for no apparent reason.

Also the props are extremely draggie at flight idle depending on how they are set up. If they are set low and you are still a couple of feet off the deck and you bring them back to idle unless you time the flare perfectly as she stops flying that 4" of gear travel doesn't soak up much.

The controls if you don't keep her trimmed right can get extremely heavy especially in high crosswinds and most of them only have a manual trim wheel. And it has a stupid spring thing thats meant to coordinate turns but you have to fight against it for cross controls.

Everone has a play with falp 20 landings and in my experence it makes sod all difference and just makes the rollout more challanging because the flap 70 lift dump doesn't deploy.

The J41 has different gear only has flap 20 instead of flap 35 has much more air over the wing at flight idle. And is much much more predicatable if you get the numbers right.

mad_jock

13th Feb 2012, 13:31

Just to add to Beagles post the civi ones seem to have the roll sorted out but they still can be twitchie in pitch depending on the C of G.

Taxing you really need to use brakes,tiller and power coordinated to get it smooth. And then you have the different types of tiller one a star shape with a big arrow head sticking out or a handle type affair. If I was to brute force the steering on the star shapped one I would end up with RSI. Did one days worth of compass swing with one of them and I was in pain for a week afterwards.

And the Garretts are a bit of a pain to manage compared to a PT6 but are pretty good really considering the 25% fuel saving for having a direct shaft and they have a really high TBO. I have never heard anything good about the french engines.

And the AP's are still ****e. You just think its about to capture LOC then it runs out of servo trim and buggers off in the wrong direction usually decending rapidily approaching Vmo. Not that there are many AP machines out there I think only 20 were produced and they are heavy.

Keeps the day interesting though, not many aircraft out there though where you can cut your teeth flying everywhere manually IFR multi crew.

peterh337

13th Feb 2012, 14:20

And the AP's are still ****e. You just think its about to capture LOC then it runs out of servo trim and buggers off in the wrong direction usually decending rapidily approaching Vmo. Not that there are many AP machines out there I think only 20 were produced and they are heavy.And this aircraft is CAA approved for public transport?

To carry how many?

How can that be?

:ugh:

What country is this? The Belgian Congo?

I thought that the "CAA approved" Trislanders going to Jersey were totally outrageously unairworthy heaps of ****e, but it seems that the payment of an AOC approval fee is a fix for all the things which could not be fixed with duct tape.

If the bit I quoted is really true then there is something deeply perverted with aviation regulation in the UK. It might also help explain why there are so many "professional pilots" here on p p r u n e with perverse attitudes e.g. believing that the ATPL ground school is somehow relevant to flight. And it would explain a lot of other stuff which is deeply wrong with aviation here.

Any plane which does what MJ says should be grounded before further flight.

mad_jock

13th Feb 2012, 14:24

I think this is a mark 1

http://i25.photobucket.com/albums/c67/sabamel/Aircraft/Cockpit%20quiz/Cockpitquiz291.jpg

And this is a civi J31.

http://i25.photobucket.com/albums/c67/sabamel/Aircraft/Cockpit%20quiz/BritishAerospaceBAe-3103Jetsream31.jpg

19 seats
G reg.

I think there is only 2 AP J31's left now on G reg BTXG and LUVB both of them are pretty good or were the last time I flew them.

The biggest heap of crap jetstream I have ever flown was a N reg one that heap really was a dog, two reds perm on the cap panel so restricted to below FL100 and nothing in the baggage bay and about 4 ambers. Didn't take that job and you wouldn't be allowed to fly it in the UK.

Why ground it? Enter it in the techlog, engineers defer it pull the CB's then fly it around manually which is what you do with the other 95% of J31/J32''s. The gingers do something to it and announce its working again and you use it again. To be honest if wasn't for the fact that pulling the AP out is a major mod and I was told would cost 20k plus for approval all of the AP's would have been pulled out years ago to get 50kg reduction in aircraft weight.

They are actually a very safe robust aircraft, there isn't alot that can go wrong on them that you can't sort out. They are cracking in rough crap wx and are built like a brick ****e house. There was one incident in the UK where one was landed with a recorded landing G of over 6g. The plane was a write off but all the punters walked away, in fact one of them said to the local newspaper that it felt like a normal landing.

And you are right the ATPL's have to cover everything from crappy turboprops and ****e twins up to the latest Q400's and Boeing/Airbus Models. I have operated Jetstreams from the Faroes to the west across to India in the East. And from the artic circle in the North down to Capetown in the South And I have found quite a bit of the stuff in the ATPL's quite useful.

BackPacker

13th Feb 2012, 14:59

I like the Garmin handheld on the coaming!:ok:

mad_jock

13th Feb 2012, 15:20

Thats not standard it has a trimble 2101.

It would be out in a second if I was flying it. Those posts are bad enough for blind spots with out that thing stuck there. It certainly isn't normal. But then again it might be in Estonia.

Its got TCAS but no EGPWS its ES-PJG cn 701.

flybymike

13th Feb 2012, 15:25

I was going to remark with incredulity on the lack of an autopilot but Peter beat me to it. (Reminiscent of the Cork (metroliner?) non AP crash.)

all the punters walked away, in fact one of them said to the local newspaper that it felt like a normal landing.

He evidently didn't know how close to the truth he was.

mad_jock

13th Feb 2012, 15:39

Cork was nothing to do with the aircraft although it is of the same stable.

Cork was all to do with the operating culture and who was sitting on the flight deck.

The AP wouldn't have been in on the go-around anyway. They shouldn't have been there full stop.

AP's go tech and then its usually a 10 day fix on TP's.

flybymike

13th Feb 2012, 17:25

Some on the Flyer forum thread thought the absence of an AP may have been a factor, but of course (as usual) this is all conjecture.

mad_jock

13th Feb 2012, 17:51

An AP doesn't decide to bust an approach ban.

An AP doesn't decide to make three attempts.

Jetstreams, Shorts 360's and HS 748's have been flying round the UK for years without AP's in all manner of ****e wx without crashing when it gets a bit foggy.

Then again there has more than likely been thousands of command decisions of "fark this for a game of solders, tell the boy we are diverting"

silverknapper

13th Feb 2012, 18:00

Some on the Flyer forum thread thought the absence of an AP may have been a factor, but of course (as usual) this is all conjecture.

Garbage. Autopilot or lack of had nothing to do with it.

peterh337

13th Feb 2012, 18:20

Unfortunately, much as the weathered old sea captains (http://images.dpchallenge.com/images_challenge/0-999/479/800/Copyrighted_Image_Reuse_Prohibited_319934.jpg) like to pretend otherwise, not using the autopilot does matter, simply because no matter how fantastic a sky god you are, having an AP (I mean a working one, not one of the rubbish ones which MJ has apparently been flying with in those barely airworthy scrap heaps) reduces cockpit workload by an order of magnitude.

That in turn means you have time to think and work out what to do. You are better placed to evaluate trivia like the missed approach procedure and the diversion options. The Irish crew where probably knackered through the hand flying in crap wx and were keen as hell to get on the ground.

silverknapper

13th Feb 2012, 19:08

Peter

I hope you don't mean me. I never dispute that autopilot is a wonderful tool, even a basic wing leveller allows one to relax in the cruise and spare some capacity to manage the flight.
However in the case mentioned, ie Cork, it had nothing to do with the accident. I know you don't hold people who fly for a living in any regard, but hand flying for an hour or two is no big deal, a pain in the backside perhaps but not an issue. A good crew will assist each other, take a shot each in the cruise if it's a long trip etc etc. Indeed the practice that hand flying gives means that their manual flying skills will be first class, and shooting approaches manually second nature.
Sadly in this case poor decision making seems to be the cause. Three approaches to an airfield they were never going to get in to legally, ignoring the approach ban, refusing to divert and continuing below minimas all point to blatant pilot error. The interim report just published also mentions the power levers being brought into the beta range whilst airborne. Lethal. It also mentions the Captain operating the power levers whilst the FO flies. Again this shows poor judgement and a disregard for basic CRM.

mad_jock

13th Feb 2012, 19:10

Yes the AP does reduce workload Peter.

Approach bans were brought in for a reason. They do work.

Have you actually read what they did?

http://www.aaiu.ie/upload/general/13067-PRELIMINARY_REPORT_2011_005-0.PDF

There is nothing to think about if your given an rvr of 300/350/500 and your CAT I only. If you have an AP or not.

Then to be given 350/350/400 and to continue to go around at 100ft agl. off a CAT II runway which lighting is all I can say is impressive.

Then have another shot when it was 350/350/350 and bust it this time by 110ft

Then have a go again when its 500/400/400 again to bust mins by 100ft. then to unfortunately crash off the Go-around. Which I might add even if you do have a AP would be disconnected as soon as you pressed the TOGA button

For those that don't know CAT I is 550m RVR and CAT II is 300m.

I really really can't see how an AP would have changed matters Peter they should have never left the hold.

All IR pilots both professional and private should have a bloody good read of that report.

O and I don't think using either the GPS or ADF would have effected the out come in this case.

peterh337

13th Feb 2012, 20:08

Yes I agree it was lousy decisionmaking, minima busting, etc. They should have diverted right away.

But I don't accept that a crew flying by hand is - for any given level of competence - going to be as fresh as one assisted by an AP.

Aviation is full of cases where people do apparently stupid things. I bet most of them would not have made them in an armchair. Perhaps not even AF447? :)

And even if these crazy pilots did proceed with the approach (as they did) to Cork, if they had an AP which actually works they could have flown with it, tracking the LOC/GS down to about 50ft. Stupid and illegal yes, but it would have worked out fine.

It is not a matter of whether I hold people who fly for a living in regard or not. Actually I do very much and have always enjoyed flying with such pilots because I can usually learn something from them. What I don't like is (some) people being pompous about it.

BEagle

13th Feb 2012, 20:21

I always remember the 'limitation' which applied to one F-4 aircraft I once flew:

"Autopilot must be used with caution. May cause random +4G pitch moments"

I don't think anyone ever used the autopilot in the F-4 even when it was allegedly serviceable. Even on the few occasions we flew airways.

I don't think we had ADF, let alone GPS. Just INS and TACAN.

mad_jock

13th Feb 2012, 20:43

Crazy as it sounds sometimes if your knackard hand flying perks you up. Gets your hormones running and mind working relieves the bordom. It actually forces your SA up a gear as well. Until you have done 6 days in a row flying 4-8 sectors a day starting at 6am then moving after three days to starting at 11am finishing at 9pm or later you can't know the feeling and thats not ment to sound pompous.

So after they have flown two approaches with no deviations to note on the report your solution would be to have an Autopilot and then to decend down to 50ft (and they had aready been down to 90ft) which is 150ft below thier mins in a 7 ton TP travelling at about 130knts? And to be honest you and I don't know if it would be fine.

I don't think we had ADF, let alone GPS. Just INS and TACAN.

But did they not send a bloke along to supervise you and deal with that sort of thing?

peterh337

13th Feb 2012, 20:51

Gets your hormones running and mind working relieves the bordom

That sounds good; I must try that :)

Let me see if I can find a female IRE for my renewal :)

madlandrover

13th Feb 2012, 20:57

Kath B :E??

silverknapper

13th Feb 2012, 21:19

Maybe Kath needs a logbook MJ. You could sell her one.

mad_jock

13th Feb 2012, 21:20

Aye true thats when I started to be scared of her :p

Johnm

13th Feb 2012, 21:50

FWIW no-one in their right mind would fly an NDB procedure using an ADF if they had a suitable alternative such as any old GPS which can tell you what TRACK you are following.

MarcK

14th Feb 2012, 00:37

The EGNOS and WAAS ground stations provide correction information to the transponders on the GeoStationary satellites. You don't receive the ground station information directly.

BEagle

14th Feb 2012, 06:06

The EGNOS and WAAS ground stations provide correction information to the transponders on the geostationary satellites. You don't receive the ground station information directly.

Not according to About EGNOS | EGNOS Portal (http://egnos-portal.gsa.europa.eu/discover-egnos/about-egnos) . There's a useful videoclip on that site which explains how EGNOS works. Ground infrastructure receives normal GPS signals which are then checked and any error corrections are sent to the geostationary satellites (Inmarsat and Artemis, soon to be replaced by new Astra satellites). Those satellites then send corrective messages to EGNOS-enabled receivers.

My (wonderful) Garmin had EGNOS reception selected ON; today I'll try ith with EGNOS reception selected OFF and see whether I get similar accuracy.

GPS satellites are in lower orbit (20000 km) than geostationary (36000 km). Given that many vehicles in the GPS constellation were in orbit a long time before EGNOS, I can't really see that a direct satellite-to-satellite link would be feasible - or that the US would welcome other nations' systems doing so.

Anyway, 'tis all magic and beats the pants off ADF!

peterh337

14th Feb 2012, 08:13

you cannot complete a published RNAV, GPS, GNSS, WAAS, EGNOS approach using such basic GPS equipment. You also as an operator require approval from the FAA or CAA together with the correct equipment before conducting these approaches.

What you can do legally is fly a non precision approach as a GPS overlay, providing you have monitored ground based information i.e. an NDB or VOR needle displayed.

Oh dear. Shall I start by asking for references? G-reg, private ops, or if you like FAR Part 91.

Contacttower

14th Feb 2012, 09:23

In the US to fly GPS approaches all you need is IFR GPS...

As far as autopilots are concerned the crucial difference is that most people on here fly single pilot IFR, for which an autopilot is very useful (although I have managed almost 3 hours without one on a number of occasions...). For multi pilot obviously they are not as important.

peterh337

14th Feb 2012, 09:31

In the US to fly GPS approaches all you need is IFR GPS...with an AFMS authorising it.

Same under EASA, actually.

EGNOS is nothing to do with this. EGNOS (WAAS in the USA) applies to LPV approaches only (GPS lateral guidance with a GPS synthetic glideslope). Currently the UK has just one of these, in Alderney, AFAIK.

And for private ops, there is no regulation (UK, EASA or FAA) specifying which navigation source should be used at any particular phase of a flight.

All that stuff about monitoring an ADF (etc) while flying an NDB approach using a GPS is out of AOC ops manuals (which in any case vary according to what the local CAA has approved). It is sensible to check the ADF (like backing up a GPS enroute with VOR/DME) but it is not a legal requirement for private ops. You merely need to carry a working ADF.

Compared to a GPS, the ADF will do little more than to confirm you are pointing at say Gatwick and not Manston :)

Who is this Cath B? Does anybody have a photo?

proudprivate

14th Feb 2012, 10:31

You merely need to carry a working ADF.

I think here is where the confusion coming from. I was writing about whether or not you still needed (legally) a working ADF on board when you have a GPS. The AIM-table in 1-1-19 is about what kind of GPS that needs to be (i.e. panel mounted IFR approved) in order to do away with the ADF altogether or to fly with an inop ADF when executing an NDB or NDB/DME procedure.

I have flown NDB procedures in the UK on an N-reg having such an IFR approved mounted panel GPS without an ADF onboard. Is that in violation of a regulation ?

Compared to a GPS, the ADF will do little more than to confirm you are pointing at say Gatwick and not Manston http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif

I hope we all agree on that.

peterh337

14th Feb 2012, 10:41

I have flown NDB procedures in the UK on an N-reg having such an IFR approved mounted panel GPS without an ADF onboard. Is that in violation of a regulation ?

Until the very recent change by the UK CAA (to which I can't find the link right now), yes.

But I don't think the UK is the only country requiring the carriage of an ADF for IFR in CAS. Last time I looked (a few years ago) Switzerland was the same, and Germany mandated it for something like night VFR.

Equipment carriage regs are an airspace requirement so they catch all aircraft flying there, regardless of the State of Registry.

The American GPS-for-ADF substitution concession is of no value in Europe.

That said, there is no evidence that any of the countless SR20s and SR22s sold in the UK without an ADF or DME have ever been prosecuted, and everybody has known about this for a long time.

soaringhigh650

14th Feb 2012, 10:54

There's a crazy amount of moaning on these forums about how NDB/ADF sucks.

Yeah, we know and we are all in agreement. Point taken.

Now why don't people get off their chairs and keyboards and actually talk to and BUILD RELATIONSHIPS WITH REAL PEOPLE and develop a Euro-wide program to get rid of this thing?

Building rapport with anonymous Internet characters ain't the best way of developing such a program.

madlandrover

14th Feb 2012, 11:03

Until the very recent change by the UK CAA (to which I can't find the link right now), yes.

Sadly, still yes - the change removes the requirement for ADF carriage for enroute airspace, not for flying approaches or missed approach procedures. Even though monitoring a GPS track is a pretty useful addition for any approach.

mm_flynn

14th Feb 2012, 15:08

Above the Clouds,

What Peter was saying is there is no regulation that requires you to be using a specific navigation aid when flying a non-AOC operation. Not that you do not require the specified instruments to be on board and working and the navaids to be working.

So there is no rule against flying an approach marked NDB while looking at your hand held GPS (although you must have a working NDB on board and the navaid must be working). Clearly you still need to follow the flight profile and if you fail to achieve that, you could reasonably by done for Careless and Reckless if you were using something clearly not up to the job. And I suspect a cheap GPS with hand entered coordinates might fit that criteria in the event of a crash that can be directly pinned on say an incorrectly entered waypoint.

The most common sensible application of this would be to fly and NDB procedure using a approach approved GPS/FMS. One would normally also of course load up the raw data as a cross check, but certainly I would be flying primarily with reference to the GPS data.

peterh337

14th Feb 2012, 15:26

Above The Clouds

Your reply/question is awfully mixed up, mixing "company manual" (AOC type) rules with old aviation chinese whispers.

So let me ask you for a reference for

and we can't do the above legally

Who actually said so?

mm_flynn has got it right (as usual).

Moving onto practicalities and safety (rather than legalities) there is a load of things one should or should not be doing e.g.

- using waypoints with hand entered coordinates (unless somehow verified beforehand) is not a good idea, especially in a shared aircraft ;)

- one should still fly the published lateral track because the obstacle clearance is based on that

- be careful with GPS "overlays" for non-RNAV approaches, pulled out of the database, as these are sometimes partial-only, with segments missing (which is why I always fly literally what is on the approach plate, using the OBS mode of the GPS, and sometimes use VOR/DME in SIDs because it is simply easier)

peterh337

14th Feb 2012, 16:05

The leaflet you reference is entitled

Flying RNAV (GNSS) Non-Precision
Approaches in Private and General
Aviation Aircraft

which is a different topic to what has been discussed. It does briefly refer to flying other types of approaches using a GPS but as with all this advisory material it is no more than the personal opinion of a person in the CAA. That is not to say it is bad or wrong, but it is not the law.

fwjc

14th Feb 2012, 19:26

Two things -

1) GPS was initially not allowed to be as accurate as it is now. The US military employed Selective Availability (SA) which is an artificially inserted "wobble" in the satellite signal. This meant that the military chaps could clean the signal and have good Nav, while the civvies and the enemy had reasonable but not super accurate Nav.

SA was turned off in May 2000. There remains the possibility that this could be turned back on again. As a result, GPS procedures remained somewhat risky, since they _could_ turn on SA and mess up all the global approaches just like that. However, differential GPS techniques had already started to overcome this problem.

Several things have happened since 2000. For the first 5 years or so, use of GPS tended to be limited to specialist, niche arenas such as maritime and aviation. In the last 7 years, global use of GPS technology has exploded particularly with in-car navigation, but also with multiple uses ranging from stock management to improved emergency services deployment, and these days most people in the western world have some sort of smart phone with a GPS device.

This embedding in day to day life makes it much harder for the US government to make the SA call, since the knock on effect could be a bit of an own goal, not that the US have a reputation for that.

In addition to this, there are now additional satellite constellations coming online which mean that the reliance on US systems is less of a concern, plus DGPS is well developed and reduces most of the SA error.

Both of these factors mean that considering GPS procedures is _now_ a much more realistic proposition.

Actually, imo, the biggest threat to GPS navigation right now is not the US government, but the sun. The current solar sun spot activity maximum and increase in number and intensity of Coronal Mass Ejections - Solar Flares means a greater likelihood of satellites in one part of the sky being knocked out (electronically) for a period of time. If you're unlucky, you could be caught out with reduced accuracy (read up on GDOP for the theory) due to relying on signal from one other part of the sky.

This is a small risk, but nevertheless it exists.

2) Talking about using handheld GPS for navigation, at least one police force I know was using a PDA with Memory Map as a navigational aid in their heli back in 2004. This was in addition to all the usual kit, but velcro'd to the kneeboard the handheld was definitely in use.

I'd rather have everything available to me - GPS, RNAV, and Mk 1 eyeball. 2 out of 3 would be my minimum, and I wouldn't like to lose any of them as a long term option. Just imo.

peterh337

14th Feb 2012, 19:38

I too think the USA is hugely unlikely to reintroduce SA (or some other form of it) because it would be a huge economic own goal.

However GPS with SA (as SA was when we had it) still delivered a navigation accuracy about 10x better than NDB tracking.

Regarding Galileo, I am certain that there is a secret agreement between the EU and the USA whereby EU would shut their system down if the USA shut theirs down (or shut down the civilian signal) as a result of coming under a missile attack (or similar). So the extra protection provided by Galileo, in the already incredibly unlikely event of a US shutdown, is illusory. As in WW2, GA and much other aviation would be banned immediately anyway.

Those who think that conventional navaids provide some magical protection against subtle failures can read this (http://www.peter2000.co.uk/aviation/hsi-failure/index.html). And this (http://www.peter2000.co.uk/aviation/pontoise/index.html) shows the kind of dangerous conventional IAP which might get flown as a result of such a failure. In comparison, with GPS the equipment failure is normally really obvious (with any remotely modern equipment).

n5296s

14th Feb 2012, 20:10

Those who think that conventional navaids provide some magical protection against subtle failures
Better (or actually a lot worse) yet, the not-quite-crash at Addis Ababa that I read about on here a little while back (can't find the reference now). The VOR had been serviced and an unapproved fluid had found its way into the phase shift electronics, causing the radials to be off by quite a lot.

WAAS and EGNOS require training in the sim.
This is nonsense, at least as far as WAAS goes. Maybe true for individual operators, but as far as the FAA is concerned all you need is an approved WAAS capable GPS installation (and an IR) and you're good to go. And why not, since flying an RNAV approach is no different from an ILS?

n5296s

14th Feb 2012, 20:34

Lets see how far you get completing a WAAS approach that states RNAV (RNP) or SAAAR on the chart then
That's completely irrelevant. There are loads more WAAS-based RNAV approaches than RNP. RNP approaches require special equipment as well as approval, which no small GA aircraft have - probably not very many big ones either.

Final 3 Greens

14th Feb 2012, 20:38

Say what you will about ADF, it is a great way of finding your local CB cloud.

Big Pistons Forever

15th Feb 2012, 03:19

So there is no rule against flying an approach marked NDB while looking at your hand held GPS (although you must have a working NDB on board and the navaid must be working). Clearly you still need to follow the flight profile and if you fail to achieve that, you could reasonably by done for Careless and Reckless if you were using something clearly not up to the job.

This is a real danger. When the authorities see that you have exactly followed the inbound track with no significant deviations they will know that you have been following your $ 500 hand held GPS track guidance instead of the $ 5000 installed ADF :=

Better avoid enforcement action by turning off the GPS and providing a nice wandering approach track that ends in the general area of the runway. :E

mm_flynn

15th Feb 2012, 05:47

This is a real danger. When the authorities see that you have exactly followed the inbound track with no significant deviations they will know that you have been following your $ 500 hand held GPS track guidance instead of the $ 5000 installed ADF :=

Better avoid enforcement action by turning off the GPS and providing a nice wandering approach track that ends in the general area of the runway. :E
That is a very wise suggestion, as GPS is in fact 'The Work of The Devil' and one risks being cast into the hell that is arriving exactly at the destination if one uses such blasphemous tools. ;)

peterh337

15th Feb 2012, 06:27

The simple solution to that would be to create a few user waypoints a couple of miles either side of the inbound track :E

For extra authenticity you would create a big dogleg at about 2D - 3D, for any coastal airport :E

But all this work would be wasted unless the airport has radar, or you crash in which case the AAIB will retrieve the radar tapes from the nearest radar unit :E

FlyingStone

15th Feb 2012, 08:05

Say what you will about ADF, it is a great way of finding your local CB cloud.

... or listening to AM radio stations :)

This is a real danger. When the authorities see that you have exactly followed the inbound track with no significant deviations they will know that you have been following your $ 500 hand held GPS track guidance instead of the $ 5000 installed ADF.

Better avoid enforcement action by turning off the GPS and providing a nice wandering approach track that ends in the general area of the runway.

True :) Actually, the ATC (radar-equipped) expects you to fly exactly on the extended centerline even when flying a non-precision approach. I got vectored back to the actual centerline when for example the both CDIs were centered for VOR/DME approach, since ATC thought I was overshooting the final track - I assumed it's because everybody is always flying non-precision approaches with GPS guidance and using the actual navaid just for backup/monitoring.

Although I seriously await the day when one would be punished/warned by the CAA for flying the non-precision approach too accurately (e.g. with GPS) instead of following the needles. I consider the approach flown with GPS guidance to be almost a precision one, since it gets you directly to the runway threshold, mostly lined up with centerline. On the other hand, traditional non-precision approaches get you somewhere in the vicinity of the airport IF the weather is good, IF it isn't dusk/dawn, IF there isn't some electric activity around, IF the airport isn't too close to sea, IF you keep wings level throughout the approach and IF you're VERY lucky, it gets you within +-10° of runway heading.

I really don't understand people who fly approaches with GPS if you can fly much more accurately using the traditional navaids :E