ILS Outer Marker Check heights

[FishHead]

A technical question if I may....

AIP states (in ENR 1.5 para 7.3.1) that
On final approach the aircraft altimeter indication must be noted at the fix or facility. If the aircraft altimeter indicates a higher altitude than the check altitude, the difference between the two altitudes must be added to the approach minima. If the aircraft altimeter indicates a lower altitude than the check altitude, corrective action is not required.

The RAAF FIHA says the same thing on page 157....

However, this assumes that you are dead on glide-path at that point.
What do you do if you are off glide-path, whilst remaining within limits for the approach?

A suggested answer.... continue with the approach, but revert to Localizer minima?
Another answer (although less helpful)..... don't be off glide-path at that point!

I'm curious as to whether or not people have SOPs laid down for the 'off glide-path' case.... perhaps not if your coupled auto-pilot never lets you get off glide-path! In particular, I'm looking for authoritative guidance on what to do...

Many thanks in advance.... you'd never guess I have an IRT due in a week!
:D

[Chimbu chuckles]

I wouldn't worry so much about trying to work out 'offset' corrections as they will be very small if you are within tolerance...possibly too small to pick up with any certainty on the moving altimeter needle.

What you should be doing to prepare for your upcoming IRT is understanding why the corrections at all and why none required if you are indicating low.

Reasons;

1/. Simple gross error check in the case of forgetting to reset your altimeter from transition level or area QNH to local/station QNH.

2/. Temperature correction (ISA Deviation) for the altimeter.

Chuck.

[alphaball]

Grab your flight manual and work out what 1/2 full scale glideslope is (probably around 0.35 degrees)

Then use basic trig. to work out what altitude difference that represents at a generic OM distance.

Is it worth the effort...no. Outer marker distances vary at different airfields so your Rule of Thumb will never be exact (unless you crunch it each time!!)

The answers mentioned in your post are probably what your IRE wants to hear.

If you want to delve further into this issue work out what temperatures equate to particular altitude adjustments atthe OM check. I don't think it is very significant until down around 5 degrees celcius. I did know a rule of thumb but have forgotten it due to lack of use.

If you know what the altitude correction is likely to be, due to cold wx., then you will be ahead of the game at the OM.

I would ask your IRE what limits he is willing to accept off glideslope and still call it a valid OM check. It may be written in an SI or training manual somewhere. I know it is in some FEG's.

[Chimbu chuckles]

+/- 4' per degree of ISA Devn x (alt/1000)

The above works to within a few feet until you start getting to bizarre cold and many thousands of feet above the (temperature) datum.

example;

1/.
ISA - 15/ MSA 4000'

(+ 4 x 15) x 4

altimeter overreads by 240' in this case.

2/. ISA - 20/ minima on ILS 200' @ sea level destination.

(+ 4 x 20) x .2

altimeter overreads by 16' in this case.

3/. ISA + 20/ OM check altitude 1500'

(- 4 x 20) x 1.5

Altimeter undereads by 120' in this case.

Clearly the last example is the most common one we experience around Australia (well the top half anyway:D ) although Taswegians could easily see the first two occasionally...Victorians too but only for a few minutes before seeing example 3 again:D

Remember that your Barometric Altimeter measures the height of a column of air that would go all the way to sea level if the ground 'wasn't there'. If it's really cold (dense air) that column of air will be shorter than if it's really hot ( all the little air molecules bouncing off each other and taking up more space:D)

Given the above it is obvious that you will be lower in cold air while sitting atop your 1500' column of air at the OM than when it is ISA (which it virtually never is so your altimeter is always going to be 'wrong')

Clearly if on GS over the OM and your altimeter says you are at 1500' and you are actually at 1380' that is dangerous. If on GS over the OM and your altimeter says 1380' when you're at 1500' then no drama.

Remember that if your are on GS over the OM you ARE at the published height, if your altimeter says something hugely different there are limited reasons why.

While really cold weather can cause a dangerously over reading altimeter it would be unlikely to kill you except while doing something like a NPA into a high elevation airport...hardly common. Or descending to a really high LSA/ MSA.

By far a more (potentially) common mistake and far more likely to be fatal in warmer climates is forgetting to station QNH on descent.

Imagine you're tooling along in the FLs in your Kingair/C340/C421 whatever, single pilot at 0430LT ! You forget to reset your altimeter to the station QNH of say 1006 for the ILS and the weather is right on the minima of, say, 450' (200' atdz).

See what I mean about a gross error check?

It is not a whole lot less scary if you've been cruising below transition in your Baron on an area QNH that could be +/- 5 mb of the station QNH.

If you do nothing but add the difference at the OM to your minima at least you wont die...but of course now you have the nifty little formula you'll be able to predict, within a few feet, what the altimeter should say at the OM:D


Chuck.

PS. Anyone notice the flaw in the just add the difference at the OM rule?

[Blue Heeler]

Chimbu,

That formula works for height above altimeter source, not ht above AMSL.

[Chimbu chuckles]

Yep...you're only interested in the temperature deviation from ISA at the destination...sorry if something in my previous post indicated otherwise.

Chuck.

[donpizmeov]

Fishy,
I remember one of your favourite past captains use to beat you over the head about this a few years ago!!!
I think he mentioned you had to use your common sense old boy. Remember that in the warmer air that you fly in (yes even EDN on most winter mornings) it would be very rare to see see an altitude higher than published for the check, so it would be rare to have to make a correction. Sooooo, if the young lad you have flying is a little high/low on the glide (as I know you would have it pegged!!) make sure the hieght you see looks sensible (ie in the correct sense!). The error will be so small it will make little difference. Our seal bashing cousins from the frozen north, even use the rad alt to check the check height (using the agl alt, or QFE alt for the poms! you know the one).
There is no need to revert to an LLZ MDA unless everything is going pair shaped, in which case a miss and a cup of coffee might be more to order.
If you are really unsure, perhaps a quick look at the DME Vs Alt will put all back to order for you.
Anyway EGWPS will look after you (and it has more personality than a Nav!)
Good luck fishy, you will once again prove yourself a star, I am sure.
Don

[Time Bomb Ted]

Aren't we the only ones on the planet that do them or am I mistaken?

[FishHead]

Don,

To answer/refute one by one.....

1. I was abused in many ways by that captain you refer to... something I'm still trying to deal with, so thank you for bringing it up.

2. You know what they say about common sense - 'it ain't that common'. More importantly, since most of my IRE's are QFIs, common sense isnt a valid justification for them.

3. I take the point on temperatures, and the fact that the sub-tropical environment I work in will results in very few 'over-readings'...

4. When young Bloggs (as you surmise, I personally would never be off glideslope) is pushing the limits, and finds himself 1 dot high or low whilst shooting an ILS at a hypothetical military airfield in South Oz, doing the maths (involving a bunch of sin formula, which I won't fill your little head with), he will actually be 115ft off the check height. This is probably outside the 'insignificant, so don't worry about it' bucket.... Having said all that, the last thing I want to do at that particular point of an approach is work out the sine of 3.25deg - so as far as I can see, I am left with the option of going with my gut, and saying, 'that looks about right'... but no facts to back it up, other than my years of maritime experience....

I guess the short answer is that whilst I am happy to go with my gut feel, it seems a somewhat wishy washy response to what should be a fairly cut and dried matter.

Chimbu,
I am quite happy with the reasons why regarding temperature corrections, but my agenda lies more in the fact that I am looking at getting to the lofty heights of IRE myself in the near future, and I want to be able to give a snappy sounding answer when the young pups of today come-a-askin'

Alphaball,
I guess my problem lies in the fact that there is no published guidance in the pubs that belong'em my FEG.... happy to hear if you have some that you can offer though!

[Trash 'n' Navs]

Fish, a little bird told me that the the requirement for an OM Check is going to be removed from the Civvy pubs in the not too distant future. I don't think a decision has been made about what to do with FIHA.

If I hear a confirmation I'll let you know.

[The Messiah]

Sorry but I think you are all overcomplicating the issue as usual.

The reg says nothing about being on slope, only that any height above the check height must be added to the minima.

So as long as you are in tolerance, but above slope, you must add the entire difference to the minima........moral to the story, stay on slope.

[Chimbu chuckles]

I are a company IRE and the only time I get asked hard questions is when Griffo does me renewals:D....shamefull state of the industry I suppose.:D

As for adding the extra height over the OM if you're a dot high?

I don't farking think so!

But no-one has answered my question!

Chuckles.

[Kaptin M]

The check at the outer marker has to be done in conjunction with a DME, otherwise how will you know when you are precisely over the O.M.

This question is really purely semantic as the reason for the height check is to accordingly adjust the D.H., which at ISA minus 20 is still only going to be a correction of 16 feet.

Time to go and play with another knob, boys!

[Chimbu chuckles]

Ya right:D

Like I said...tis just a gross error check.

But I get a kick out of rules of thumb an handy little formulae.:( :D

Fishhead...if ya get some smart arse just askim what the difference is between OCA and MDA? thatllfarkim...for a while:D

Or a ripper that I was asked once....what is the different timing of the idents on VOR/NDB and DME?

MY answer? DUNNO and dont care!

Sprucegoose then proceeded to baffle me with BS...so I timed a few and they are all over the place...turns out the Goose still had his old blue DCA Navaid booklets that the rest of us threw out a couple o' decades ago....things have changd since the 70s:D

Twas bloody funny watching him time idents on the next several sectors.

If you want to be a good IRE then stick to good practical stuff...make damn sure your candidates can pass a solid, searching test of their ability to apply the AIP to everyday IFR operations....minimum BS minutae...lest you be labelled another one of those point scoring ex mil dickwits that are so common in various areas of Australian Aviation.

I fired a young F/O a year or so back because despite the fact that he had an Instructors Rating, command IR, ATPL, Degree in aeroplane husbandry and 1600 odd hours he COULD NOT fly an instrument approach to save himself. He could not answer even basic AIP questions and generally had NO IDEA!!

He wouldn't even make an effort and is now back instructing and presumably flying single pilot IFR Charter again :eek:

I had to draw pictures to explain to him how an RMI worked...like no mental maths with relative bearings required fool:eek:

Ever seen a young Instrument rated pilot (different guy) who had probably 4 renewals who didn't know how to orientate the CDI so it would give him command indications when tracking outbound on a LOC...I have.

Sorry if the above is off thread, but really there's lots more important stuff.

Chuck.

[olderairhead]

A few points to remember when checking your height at the OM to obtain a correct altimeter reading:

1. You have to apply PEC!

2. Know your DME. As an example do not read the altitude at 5 DME. When your digital DME changes from 5.1 to 5.0, your actual disatnce is 5.09, .1 of a nm makes a difference!

3. Also needed is an accurate QNH!

When combined your error can be up to 150 feet! (Depending on a/c)

The requirement to check at the OM is very valid indeed.

[Rabbit]

A lot of good and very technical responses above but now lets be practical. We have a lot more to be concerned with during approach that trying to calculate altimeter corrections. I have had some very simple and practical advice given me when I was checked out at different times for both Aus' and UK IRE qualification in the past. Yes I aggree that there are corrections however lets look at the approach. The ILS is a precision approach where the minima mostly is preset depending on the approach category. CAT 1 normally 200ft above the threshold, CAT 11 normally 100ft above threshold and so on. In most cases no reference to obstacles, therefore, providing you are within the limits the corrections mean very little in practical terms. The only value the check realy provides is for a gross error that is most likely caused by failing to have QNH selected(and it does happen). There is also the difficulty in determining the precise point of the check (dme or Locator), which means small deviations are impossible to accurately determine. So in practical terms unless you are flying in sub zero conditions, only react to gross errors, small deviations can be ignored.


Have a nice day

[donpizmeov]

Fishy,

All points well taken. Sorry to hear of the abuse, but I am sure that moral improved because of it ( for the rest of the crew of course! Thats when they were not throwing up because someone forgot how to use the rudders!).

Lets see, young collegeboy under training is 1 dot high on the approach, and hits a 4nm OM check at 1315'. Sh@t he thinks to himself, I am really high, best I add 115' to the minima. Well I am pretty sure it will take all of the next 4 miles and then some for him to work out what DA plus 115' (thats your number OK!), as he still thinks you are going to fail him for his shocking flying (bet he has already done the over water stuff, and is still scared!). Best he says I am high, that agrees with the indications, and concentrates on trying to get back to the glide, and getting the approach stable (thats the common sense thing I was talking about).
I would be concerned if he crossed the fix one dot high as above at 800', and did not question what was happening.
I know that the glide does not cross the threshold at 0', and I don't remember water washing over the runway all the time, so I guess it is something above sea level as well, so all heights have been simplified due to another good weekend in Perth.
You were quite correct with your thoughts re QFIs, but there is the odd nice one around, who knows something (Dunnie for example.)
Don

[Cougar]

Fishy,
This one came up on an IRT quiz a while back and got everyones knickers in a knot. FIHA, as you have stated, does not have a definitive answer to it - a large grey area exists and no-one seems to have an answer that the rest of us agree with.

I have even asked numerous IRE's across the country and get different answers each time. The way i go about it is: on glideslope at check height, all good. Within a small error still all good, (use a bit of nouse), once you get one dot low, and convert to loc appch. One dot high and also convert as cannot check the accuracy. I have heard mentioned that if you miss the Check you can go off the DME heights on the bottom of all RAAF Terminal plates but i have heard this one shot down by numerous people since and therefore do not use it myself.

Best bet, ask IRE's, QFI's or STANDARDS FLT.
Cheers mate.

[ruprecht]

Cougar. FishHead did ask a QFI/IRE in Standards, that's why he's here!

To my mind (danger, danger!), being significantly off glidepath is the same as missing the outer marker check altogether, ie. you cannot accurately check your altimeter, so therefore should not continue to the ILS minima unless you can check your altimeter via the DME or radar or whatever. Exception would be high on glidepath but indicating low at the check. Common sense should apply, but remember that in the end we are trying to alter our DA by a precise amount and if we use rules of thumb then the alteration will be less than precise or even in the wrong sense.

Note the words 'significantly off glidepath'. I've yet to define what that actually is, but within the width of the glideslope needle on the P-3 is a good guide. Another problem, as mentioned by someone else, is actually picking the exact point you pass over the OM.

So if Collegeboy misses the check at the OM next Tuesday, he should convert to localiser minima if he can't verify his altimeter by other means.:p

ruprecht.

[Chimbu chuckles]

So we are to understand that in the RAAF if you are not on slope, within a needle width, at the OM check you throw away the GS and turn it into a LOC only?

I've never heard of that being done in any of the airlines I've worked at......I've never heard of that ever.

Chuck:confused:

[ruprecht]

Creeeeeaak. (sound of can of worms opening!)

Chimbu. Not commenting on RAAF policy at all, just attempting to define the un-definable -- 'significantly off glidepath'.

Besides, it's a well known fact that we have larger than average needles at P-3s.:D

ruprecht.

[Chimbu chuckles]

I think too much is being read into the OM altimeter check...sure if you forget to do it all then your in a bind....but on a typical day ISA is just a theory and therefore the altimeter will never say the exact check altitude.

In 9000 hours of IFR RPT & Charter I've never seen it.....usually in Northern climes you're most likely to see it underread by 70 to 100' at the OM...so you're a little high on GS at that instant...perhaps even 1 dot (not me you understand :D)...just get back on slope and get on with it.

I suppose down around East Sale it's probably ISA a lot more often...but still common sense must prevail.

For my money if the candidate makes mention of the approximate temperature deviation he expects to see, PCE if required on that aircraft, flies a nice controlled ILS within tolerance and completes the OM check (with any sensible correction if altimeter is indicating higher (very rare in Oz) then he just earned 9.8 out of 10. Few of these mental gymnastics happen while flying the approach...they were taken into account prior to TOPD.

As for syn angles...give me a break.

Lets face it 99.9999% of the time the only way you'll see a significantly 'overreading' altimeter at the OM is if you forgot to reset it... and the temperature correction required reduces to a value so small as to be almost unreadable on the altimeter unless it's arctic outside.

The aim of the game is to get to the published DH safely and land...not dick around in IMC.

IMO.:D

Chuckles.

[toma60641]

There is an important reason for doing the altimeter check - The altimeter may be in error!

Of course, you checked the altimeter(s) when you taxied out and they were within the 60-75 ft limits set by AIP ENR 1.7 p1.2

But, what has happened to one of the altimeters during the flight? Does it have the same error as you saw on the ground? Which altimeter may have the "increased error" anyway - the pilot's or the copilot's?

You cannot tell what is going on and which altimeter seems to have the "increased error" until you do the altimeter check during the ILS approach.

The AIP states that you MUST conduct the check.

Therefore, a common sense interpretation of the requirements is that, if NOT on glideslope at the check point, you must proceed with the LLZ approach, or, conduct the missed approach and have another go.

[donpizmeov]

OK, so let me get this right. Although a limit of 1 dot is quoted as being within limits for an ILS approach ( I guess someone really smart thought of this because they thought pilots were human and not triple autopilots handeling the fly-by-wire computers), the new kids on the block are now saying that if you are outside one needel width!!!! you have to fly to the LLZ MDA????? Is the one dot limit going to be amended?
I sure hope the you never fly to anywhere near CAT 1 min, as you will be shooting aproaches all day. Best you allow NO.1 to be loittered for ILS approaches to save gas as you will need it.

It is true that an altimeter may work on the ground but may fail in flight. But I guess it can also be argued that although the gear retracts OK, it might not come down again, but do we fly with them down all the time?

As said before, there can be lotsa things to influence the ALT reading at the OM check: QNH, Temp are the main ones I guess (not withstanding mech failure, rat infestation etc). If you fly somewhere really cold, you have to make the PEC corrections (Is that the same for the OM and DA?), if the temps are above ISA temp error is not a problem. A QNH error should be seen when comparing ALT Vs DME (hitting the glide at 3000' and ten miles). The OM check will check both. If you are slightly above or below the glide (ie within limits and correcting!!), and the crossing ALT is sensible with relation to the check height (IE: in the correct sense, and not too excessive), I would suggest you could continue to the ILS min.

Seems it might be a safe bet to become a TACAN specalist Fishy.

[L84Wrk]

If this correction is so important, why isn't the rest of the world doing it?
Cant remember F.A.A. but JAR does a final fix check to determine, as far as I can tell, that you have the correct ILS tuned and have not captured a false G/S, ie; a gross error check. No adjustments to minima ever prescribed. If it doesnt look right you get out.

[Chimbu chuckles]

Perhaps all those AN pilots who've just gone back into the RAAF should be made IREs....seems the system may have become a little inbred!

L84wrk,

In the northern hemisphere where it can get really cold (i.e. JAR, FAR country) if it's significantly colder than ISA you use a table to correct all ' IF app' type altitudes, MSA/LSA/minimas etc. If it's not cold then you do nothing (just like in Australia).

It is just a gross error check as you say,however failing to make the correction for ISA devn (if required) is a fail on your IRT in places like Canada, for instance.

PEC is of course a different thing again and is an allowance for position error in the probes...the flat +50' only being required if the aircraft has not been tested and an actual number found...wasn't required at all on the Falcon I've been flying the last few years.

Donpizmeoff,

Your, presumably rhetorical, question about the ISA correction being the same at OM as DH is the point I was trying to make with my question about the 'just blindly add the difference at the OM'. If a chap doesn't understand what it is about he might see a difference of +50' at OM caused by bloody cold weather and just add it to the DH when the correct correction might only be 10'...and therefore hardly worth worrying about except on an IRT:D

You'd be amazed how many pilots, including Long haul wide body Captains, who have no idea about it, or insist that Boeing's ADCs allow for it automatically:(


Chuck.

[ruprecht]

Jeez, Don! With all that sand over there, some of it must have got into your britches!

If you cast your mind way back, you'll remember that the glideslope needle in the old bomber is just under half a dot wide, so I think that this would count as being on glideslope at the OM. I'm guessing that your glideslope needle on the 777 may be a little smaller than that!

I'm not advocating being within this tolerance down to CAT 1 minima, just at the OM for the altimeter check.

It is a grey area. Do operators overseas use the OM check height at all?

r

[Mud Skipper]

My two cents,

No not even in any way is it a gross error check.

You must cross the outer marker (preferably DME height check) on slope.

If say the check height was 1500' to a minima of 200' then you would then be descending a further 1300' from the OM/DME check to the 200' minima. If you crossed the check height at say 1600' and descended to 200' indicated, then you would have infact descended a further 1400', in reality leaving you only 100' AGL at minima. This is not the intent of the CAT 1 ILS. The 100' high should have been added to the minima making it 300' indicated. You would still descend 1300' from the check position and would be at the designed 200' minima above runway.

Temperature corrections etc should have been made to the minima prior to the start of the approach. To think you could reliably do this math during the approach is unrealistic particularly after a very long day. Hopefully though we can all still add the few feet that may be required.

If you are off slope at the marker/DME check, use the LLZ minima.

Not suggesting you shouldn't use the thick black pencil though, but that I believe is the rules.


Now who is up for a discussion on the application of catagory speeds?

:)

[rescue 1]

Mud Skipper thats how I remember it as well.

Also lets not forget the NZ 767 that had a false gligeslope capture somewhere in the Pacific - glideslope checks are very important.

[Kaptin M]

Umm, I don't think so, Muddie. Using that same reasoning, the altimeter would be 100' out on landing, in which case it/they are WELL outside tolerance - unless you had inadvertantly set the wrong QNH.

The discrepancy at the OM is adjusted relative to actual airport elevation, meaning that a difference of (eg) 200' @ 1500' does NOT translate to 200' @ S.L. In fact it would be less than 20'.

So anyone who's interested in making these corrections should first check'
(a)the known altimeter error PRIOR to take off:;
(b)the PRECISE location of the OM vs DME;
(c)the DME caibrated error;
(dISA deviation at the OM;
(e)the EXACT QNH at time of passing the OM - and not the QNH at the landing airport;
(f)the parralex error due to seat position.

And just PRAY that the QNH is not even ONE mb/hp out!

Time to give it away. If there's a gross errror (spot that one?) then it's good to know WHY. But if you've done a thorough pre-flight, and followed up enroute as a PAID PROFESSIONAL will, you'll have earned your bread if you can pre-empt the OM crossing height and respond with a confident "Checked"!

[john_tullamarine]

rescue 1's comments lead to some not so well known information ..

Say what you will about ANZ but their safety culture is pretty much above board from what little I have observed. The Apia incident was thoroughly investigated .. not to cane the crew ... but to get at some of the underlying tech problems which helped the crew to set themselves up for a fright. One observation was that perhaps a number of accidents in the past might have involved similar sorts of tech problems which, while well understood by the elec/radio techs ... are generally not appreciated or known by the flight crews.

One of the main things to come out, as I understand, was a very definite tale that the ILS is a dinosaur bit of gear which works well most of the time but has a number of potential traps for young players .... it is not a bad idea to make sure that the aircraft is fed into the tube where it should be ... and that any available checks are kept an eye on down the ILS to check for any significant deviation from where you thought the aircraft might be ... markers, DME, whatever ....

I have seen a number of confused crews in sim exercises when the finger in bum, brain in neutral thought process couldn't resolve the lack of correlation between what was indicated and what was expected .....

[Swingwing]

Cougar:

I have heard mentioned that if you miss the Check you can go off the DME heights on the bottom of all RAAF Terminal plates but i have heard this one shot down by numerous people since and therefore do not use it myself.

Not sure on what basis people are shooting this down. For example, there are clearly airports where finals is flown over water, and it is quite impossible to install a marker beacon. In this case, there is no alternative but to use a DME distance vs height. Also, as some have already pointed out, this is a lot more accurate than using the beacon exclusively. Depending on the sensitivity of your marker receiver, your "overhead" of the beacon can be pretty nebulous.
All that is required (straight out of FIHA) is a "fix or facility that permits verification of the glidepath-altimeter relationship". Clearly, DME vs height is such a fix. How late you leave it is a point where there could be some debate. If you miss the OM at say, 6nm from the threshold, and don't get a check until 1nm, then you've perhaps left it a little late.
I think Chuck hit the nail on the head a few posts back - just carry out some sort of check, and make a commonsense correction if required. We are kind of "measuring with a micrometer and cutting with an axe" here, after all.

Have fun on your IRT Fishhead. Do they go for 12 hours too, just like real missions??

2 rules for IRT's:

1) 3 minutes of injudicious afterburner usage during an IRT means fuel for 1 less approach!

2)Always get the 30 day extension from your CO. That way, in a 12 year flying career, you'll do one less test than everyone else, and that's gotta be a good thing!

Cheers,

SW

[gunshy67]

Good stuff!

So if you are on slope and you check at the outer marker (albeit with the DME for accuracy) then you have checked the altimeter setting and made the correction, if any.

Why then do you need an addtional 50' PEC (assuming no AFM correction is available). I would think that you have checked the altimeter and the setting and have cross checked it with DME Marker etc.,

Doesn't that do away with the 50' add-on?

Remember the glide slope is monitored to .1 of a degree and if out of tolerance the stanby one activates automatically....?

Just thought I would ask?

[donpizmeov]

Ruprecht,

Took your advice and removed the sand. Mate, the itch went as well!!! You are good. Did you fail young fishy?
Don

[FishHead]

Wow.... I almost generated as much heated debate as the time I asked if anyone had seen the NAS proposal last year!

Many thanks for everyone's input... I guess the one thing it really showed is that there does not seem to be a recognised 'standard' when it comes to this question - perhaps that's because it really is in the 'niff naff and trivia' section. But I believe that it's not, if for no other reason than for the reason of checking that the correct QNH is set. Let's face it, the Missed Approach point for an ILS is an altitude after all, not station passage, so it's pretty important to get it right.

Swingwing:
Have fun on your IRT Fishhead. Do they go for 12 hours too, just like real missions??
Nah, more like 6 hrs.... just enough time to qualify for a chocolate bar in the inflights!
1) 3 minutes of injudicious afterburner usage during an IRT means fuel for 1 less approach!
The idea never occured to me! Will give it a go........ it might scare the Flight Engineer though!
2)Always get the 30 day extension from your CO. That way, in a 12 year flying career, you'll do one less test than everyone else, and that's gotta be a good thing!
Don't forget, go see the OC and you can push that out to 60 days!

Don:
Ruprecht hasn't failed me yet.... it's next Tuesday for the test. He wouldn't have the guts to fail me anyhow....

All in all though, since it's Ruprecht that's my IRE, then I guess my answer to his quiz question will be "convert to a localizer approach, oh god-like IRE person"

:D

[ruprecht]

Fishy. Since it'll be my IRE renewal with CFS, I think I'll steer clear of such questions as CFS are bound to have their own interpretation.

How about: " so.... when can we descend below MDA on this circling approach?"

Just remember, if it comes down to my IRE or your IRT, your odds don't look good!;)

r

[Truckmasters]

AH
The old 1 in 4 chance of the candidate passing
I luv it

[Ray Dar]

Trying to figure out who Fishy and Rupy are. If Don has something to do with it you must be "Brand X".

If you are "brand X" then doesn't the new bomber have the more officer like equipment installed like glass, FD and a new AP that does it all for you.

Take my advice opt for another emergency rather than raw data, ask the IRE for a double assy app, that way you won't have to worry about being asked about OM check heights while you are helmet-firing with the double assy app !!

Hand flown raw data approaches are not authorised after any more than 6 hrs of flight time !

[4dogs]

Folks,

While noting that this is predominantly a RAAF debate, it is a trifle concerning that the micrometer brigade have launched a take-over for the wood yard.

As an SIRE in a previous life, I used to worry about the brain power that went behind the "one foot below MDA and you fail" brigade, especially when applied to wonderful technologies like the digital readout in the F18 HUD where the actual level -off became a lottery simply as a consequence of display accuracy and system errors. Now I see it again in definitive "you must cross the OM on slope or modify/abandon the ILS" type statements.

Perhaps some of you should look upon IRTs being a check of the candidate's ability to recognise and compensate for his/her human failings while using a fairly average mechanical/electronic representation of the real world in a safe and consistent manner, rather than the alternative theory that an IRT is a legalised torture session designed to prove how clever an IRE you are and where the candidate is only there is confirm your self-assessment.

The rule is there to provide additional safety guidance, along with RADALT settings, SOPs, recency, etc. Half FSD is an IRT tolerance that reflects reality - as do correcting limits versus hard limits - and the obvious vagueness of marker beacon signals means that compensating your check altitude for temperature and actual GS indication is not inconsistent with the overall concept of a gross error check on the GS/altimeter relationship. In any event, PECs and QNH errors will ensure that the crossing altitude check will never be as precise as the charts indicate.

Standards are actually raised by encouragement and confidence building - not the opposite. TLAR (that looks about right!) is a sensible approach to OM check heights - if it doesn't look right, then protect yourself accordingly.

[Woomera]

4dogs

The Wise Owl Award is bestowed.
http://www.owlpages.com/_media_io2/tyto/masked2_80.jpg
As ever wise and directly to the point. :)

Well done guys, some excellent posts and some serious revision of the 'niff naff and trivia' that I suspect a lot of us have either forgotten or ever really got quite right. :eek: :D

Good luck on your IREs.;)

[Bullethead]

Anyone know how far off the stated OM check height you have to be to indicate a "false" glide slope ? I've reasonably often seen OM passage 150' or so higher, when on slope, than the chart check height. :confused: