Returning an a/c to Cat 3 capability

[SR71]

I'm curious to know what the rules (JAA) require in order to re-certify an a/c (for arguments sake lets say a 737) for Cat 2/3 operations, having been previously Cat 1 compliant?

Is it sufficient to demonstrate an autoland to a Cat 2/3 facility, regardless of whether or not conditions are actually Cat2/3?

Would it be acceptable to demonstrate an autoland to a Cat 1 facility in VMC?

I contend absolutely not.

I've looked at ACJ AWO 231 in JAR - AWO.....

[Wodrick]

Are you asking about re-certifying an aircraft after it has been downgraded for a defect or upgrading after prolonged operation in a downgrade state due to operator/crew restrictions ?

[SR71]

I'm thinking about the recertification after a defect has temporarily restricted the a/c to a lower capability...

[SR71]

In some circumstances where you can't be certain you've positively fixed the problem or haven't had time to do the full autoland checks we leave the autoland status at cat 1 (or 2) and ask the crews to do a 'standard landing' which is basically a practice autoland but in cat 1 or better conditions, if the crew report that they carried out a sucessful one we can again upgrade the autoland status back to cat 3.

So it is acceptable if the "standard landing" is done using a Cat 1 facility?

I find that incongruous.

JAR AWO 181(f) mentions that some Cat 1 installations are not suitable to use for autolands.....

Are you suggesting that it is common that Cat 3 certified aircraft have been returned to service based on an autoland to a Cat 1 facility?

It would seem that the very least you should do if you want to use a Cat 1 facility is make sure it doesn't fall into the category the above JAR clause refers to...

But how do you know which Cat 1 installations meet the criteria of justifiably being used to re-certify a Cat 3 a/c?

[Feather #3]

SR71,

Absolutely. Don't forget you're checking the autoland status and self-check, etc. You're not doing an approach in less than <Cat2/3 on a Cat1 ILS.

Companies [as delegates of their certifying agency] directly approve specific runways for autoland. As you say, some of the ILS runways to which we operate aren't autoland approved.

G'day ;)

[Litebulbs]

You are not checking out airfield capability, you are checking out aircraft capability. The airfield is supplying up/down/left/right. If the up/down/left/right signal fails, the standard landing fails, therefore no upgrade.

Most upgrades on the majority of jets flying where I work (UK), are upgraded by self test after a component change and never get a chance to test full functionality out on a CAT I/II/III airfield.

[Plastic Bug]

Litebulbs pretty much got it spot on, but to clarify, one should review the CAT II/III requirements at the front of the JEPP. An interesting read...

The restriction regarding CAT II/III doesn't completely lie with the aircraft, it lies with the airfield as well. When an airfield is conducting CAT II/III ops, there are certain requirements that have to be met, protecting the ILS beam etc and it's all in the JEPP.

The Airbus is allowed to do a CAT III to a CAT I runway provided the flight crew closely monitors the approach and is prepared to take over. Now, that's just a BIT of an understatement, but it's what's in the Airbus manuals.

You may have a perfectly excellent ILS, but it may not be protected to the level required to do an ACTUAL CAT III. That doesn't mean you can't shoot the CAT III approach in VMC, it just means that someone may pass in front of the localizer antennae in a ground vehicle and break the beam, disrupting your approach. That's why you are supposed to be ready, etc, etc.

Long story short, doing an autoland to a NON-CAT III runway is fine in VMC for certification purposes. Provided it works, that is.

Hope that doesn't muddy the waters....

PB

[Wodrick]

ASFKAP has given an overview of the Engineering procedures correctly, as I would expect, The other points are well made, the highlights being IN CAT ONE CONDITIONS, and that it is the Aircraft being checked NOT the facility.

It is also important to recall that in Cat One or Cat Two conditions it is abnormal to have a Protected Cat Three facility so the 'unusual' can occur.

It is only under Cat Three conditions or by special request that you would get a protected Cat Three facility, and therefore be in a position to expect the system to operate TOTALLY as advertised.

As a Certifying B2 Engineer my personal answer would have been different had you been talking about returning an aircraft to Cat Three after a prolonged period of being operated certified to Cat One or Two ONLY.

[Gary Lager]

...also remember your company may have more restrictive (although badly written) SOPs about who can carry out autolands on CAT I-only airfields! ;)

Anyway, if we needed actual CATII/III conditions to do an autoland check, how could we do one if the aircraft had only CAT I capability until we'd done an autoland? Or are the 'conditions' you refer to in post #1 more to do with airfield protections and ILS capability, rather than Wx? If so, forgive me.

But how do you know which Cat 1 installations meet the criteria of justifiably being used to re-certify a Cat 3 a/c?

With the limited information available regarding 'suitable' a/fs, perhaps give it a go in good vis and if it plays silly b**gers prior to touchdown, disconnect the automatics, sort it out and try again somewhere else

[SR71]

The restriction regarding CAT II/III doesn't completely lie with the aircraft, it lies with the airfield as well. When an airfield is conducting CAT II/III ops, there are certain requirements that have to be met, protecting the ILS beam etc and it's all in the JEPP.
PB

The JAR seems to suggest that some Cat 1 ILS installations are NOT suitable for autolands. I take this to mean that there is something inherent to the particular installation from whence this restriction derives its origin, rather than because it hasn't been "protected" during such an approach.

Which begs the question, "Why?"

Maybe in some way the ILS beam characteristics don't comply with EUROCAE ED-46/47 or other appropriate certification documents?

I was aware that we're talking about an a/c system functionality check but not knowing exactly how the autoland system works, I was not sure whether the a/c can distinguish between a Cat 1 ILS signal and a Cat 3 ILS signal.

For certification ACJ AWO 131 talks about flight demonstration for autoland and acceptable means of compliance. It involves (as I understand) up to 100 approaches during which time various flight parameters are monitored.

It seems emminently reasonable to assume that these would be to Cat 2/3 installations.

I just find it strange that a temporarily de-graded a/c can be returned to full Cat 2/3 autoland status on the basis of a "standard landing" to a Cat 1 facility...

You'd never have got it certified in the first place if you did that (because I hazard a guess many of your deviations would be out of limits), but there seems to be the presumption that if an a/c can do an autoland using a Cat 1 facility, it could easily do one to a Cat 2/3 facility.

Maybe this assumption is justified knowing how the a/c uses the respective ILS signals, but not having access to that information, I was curious to know whether the above inference is a non sequiter....

Curiously.

[SR71]

Anyway, if we needed actual CATII/III conditions to do an autoland check, how could we do one if the aircraft had only CAT I capability until we'd done an autoland? Or are the 'conditions' you refer to in post #1 more to do with airfield protections and ILS capability, rather than Wx? If so, forgive me.

I was talking about inferring that an a/c is now Cat 2/3 capable based on its performance shooting an autoland to a Cat 1 facility.

You wouldn't get an aircraft certified doing that but it appears you can get it re-certified doing it!

For the purposes of disucssion the wx is VMC, because shooting a Cat 2/3 using a Cat 1 facility when the RVR is <550 is a little daft...amongst other things...

Our SOP prohibits anybody bar a training captain doing practise autolands for training purposes.

It doesn't say anything about "autolands for the purposes of re-certification" but if the CP wants his a/c flying rather than sitting on the ground, a pragmatic approach to the problem is the way forward.

That tends to be forthcoming.

[Gary Lager]

AFAIK, an ILS system is an ILS system, whether the airfield is 'CAT I' or 'CAT III'.

The extras which make it usable with a DH<200' include, but aren't limited to, such things as lighting, local ATC LVPs, Standby power supplies, runway profiles and, of course, whether individual operators achieve CATII/III approval from the relevant authority for each airfield.

The ILS bit is usually(!) the same wherever you go. (Or at least most places I've been i.e. Western Europe)