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samfree91

ILS Autoland AP Disengage?

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Hi,

 

I am wondering if anyone out there knows the SOP's in Australia (or anywhere else if its an ICAO regulation) for when Auto Pilot is Disengaged in australia on Landing with ILS? 

Given that most australian Airports are CAT I a few are CAT II and one is CAT III i would like to know when the AP is Disengaged at all, is it;

 

  1. Upon Flare?
  2. At DH?
  3. Is the Full landing conducted manually?

How does this change with the visibility of the airfield?

 

I did discover yesterday that in good visibility the preference is to conduct a CAT I and categories only increase with visiblity, where as ive allways been flying CAT IIIb or IIIc thus far

ive looked at regualtions and some VA SOP's and none really answer this question

 

Thanks Heaps!

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Hi there,

As far as I understand, the requirement to disconnect the autopilot is based on a limitation in the system rather than a regulatory requirement. To my knowledge, Australia does not specifically certify aircraft instead electing to adopt the type certificates issued by the FAA/JAA. The type certificates would be issued based on a set of SOP's (in this case Boeing produced) which could be adjusted by an operator however that is usually done through consultation with both the regulator and the manufacturer. 

 

If you have a look in the NGX FCOM volume 1 limitations section (page L.10.5), it lays out the requirements to disconnect the autopilot both under FAA and JAA regulations. As to which one Australian operators utilise, I am uncertain and could vary between the few operator of 737. If you then pair that with the FCTM which states that a CAT II approach may be flown with either Single or Dual Autopilots engaged and that a CAT III is based on the approach and landing being flown with the automatic landing system it provides some good guidance to your questions.

  1. Unlikely. Flare is a pretty critical part of the landing process and adjusting from autopilot to manual control at that point would be unlikely. 
  2. Possible. I was taught in my training to wait for a few seconds for your eyes to adjust from the instrument scan to the visual scan. Remember that in a real aircraft your eyes have to adjust from instruments roughly 50cm away to the runway landing environment perhaps 1-2km away (which is where HUD comes in handy!). It's also worth noting that on a CAT I or II approach, as per the regulations, if you are not visual (cloud or visibility) you must conduct a missed approach. That varies with a CAT III approach that has significantly reduced visibility requirements and is planned with an autoland anyway.
  3. Based on the information in the FCOM-1, yes. If the crew were using the ILS for guidance on a visual approach they may elect to still fly the instruments either with the autopilot on/off or even flight directors on/off for proficiency and currency. Flight crew must remain current on the instrument approaches to be able to fly them in bad weather. 

Visibility would not normally effect the decision to disconnect the autopilot from a regulatory stand point but may with the individual. The visibility would however determine which approach was to be flown (i.e. if it was below the requirements for a CAT I approach then you would fly the CAT II ILS instead). That being said, there are aircrew training and checking requirements (in addition to the aircraft being certified) to fly II and III ILS approaches. CASA approval and training in a full motion simulator is required to fly a CAT II or III approach in Australia by Australian crew.

 

I would say that the information you have with the CAT I in good weather is somewhat correct but not completely. Given an ILS to fly is certainly safer in terms of runway aligned approach with a standard 3 degree profile. As you quite correctly stated, it is a preference rather than a requirement. Sydney airport prefer a visual approach via the ILS due to the parallel runway operations. It may also serve as a requirement in the conduct of a visual approach at night (not below the glidepath with less than full scale localiser deflection) amongst other items. There is however nothing stopping a crew during day operations from simply looking outside and flying the aircraft without reference to an instrument approach.

 

Hope that answers your questions. Just as a side note, PMDG require all posts within their forums to be signed with your first and last name either via a signature block or separately - even if your username is your real name. 

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Thanks very much, that helps a lot! im going to have a good read of the FCOM. That said, the australian regulations seem to rest with the airline, it would be useful to know what a pilot does with respect to each categories procedures.

 

All said, i do know that the AP Does get disconnected at some stage, the question is what stage, ill check the FCOM but if anyone else has some good info as to what procedures even a VA follows that would be great

 

As far as point 2, that makes a lot of sense, and seems like a logical time to disengage AP on CAT 1 or CAT 2, on those approaches im usually using the HGS in IMC mode as it is. CAT 3 i would definitley be leaving it on as tnats what its designed for.... i guess thag my conclusion would be that a CAT 1 or 2 Approach is designed to get the aircraft safely to runway visual distance, then disengage AP... if, the runway is seen, if not its time to hit the TOGA switch and try again, where as cat 3 is a full autoland system

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The FCOM and FCTM are both fantastic references for a lot of questions! 

 

the australian regulations seem to rest with the airline, it would be useful to know what a pilot does with respect to each categories procedures

 

I would respectfully disagree with that statement. The regulations are separate to the operations of the aircraft. In Australia we have the Civil Aviation Act (CAA), Civil Aviation Regulations (CAR), Civil Aviation Safety Regulations (CASR and meant to eventually replace the CARs), Civil Aviation Orders (CAO), Civil Aviation Advisory Publications (CAAP), Aeronautical Information Publication (AIP), Departure and Approach Procedures (DAP) and En-route Supplement Australia (ERSA). These documents all describe the safe operation of flight independent of the aircraft in operation, whereas the aircraft flight manual or standard operating procedures are completely dependent on the individual aircraft to which they apply. SOPs would also be required to not contradict anything written in the suite of regulations provided by CASA. If an airline wanted to amend a procedure it would need to speak to the manufacturer to ensure they were not making a change that could adversely affect the safe operation of the aircraft and then provide CASA with significant information to prove why the change is needed and what actions they are taking to mitigate any associated risks introduced by the change. SOPs cannot contradict the regulations unless a dispensation is sort. Essentially regulations apply to every pilot operating in Australian airspace, whereas SOPs belong to the aircraft and more or less tell the crew how to operate the aircraft in a state that is compliant with the regulations.

 

As far as what a pilot does with respect to each categories procedures, I think you will struggle to find a specific answer to that question. SOPs are not designed to be all-encompassing and assume a certain level of knowledge and experience - a product of many years of training. The FCOM states the minimum altitude that the autopilot must be disconnected by however no maximums. An autopilot is simply a device to reduce the workload of the flight crew. You can fly a 737 without an autopilot. In that circumstance the autopilot would never be engaged and the whole approach would be flown by hand. That would obviously restrict the type of approach you could fly (i.e. CAT III would not be available). You could ask the same question of 20 pilots and get 20 different responses. Remembering that it's an aid to reduce workload, the answer of when to disconnect is really "am I ready to assume full responsibility for aircraft manipulation?" I use manipulation as a pilot is never not "flying the aircraft," even with the autopilot engaged they are always monitoring and ensuring the aircraft is doing what you require it to do. Increased automation can also result in a huge increase in workload and pilot attention so in some cases it is better to just disconnect and fly the aircraft. 

 

 

i guess thag my conclusion would be that a CAT 1 or 2 Approach is designed to get the aircraft safely to runway visual distance, then disengage AP... if, the runway is seen, if not its time to hit the TOGA switch and try again, where as cat 3 is a full autoland system

 

 

Absolutely correct. Any instrument approach (other than CAT III autoland) is designed to get you to a point where you can achieve the required visibility to safely land the plane. An excerpt directly from the Aeronautical information publication which applies to all aircraft operating in Australia (with my bolding):

 

AIP ENR 1.5-9 1.10.1 A missed approach must be executed if: © visual reference is not established at or before reaching the MAPT or DA/RA Height from which the missed approach procedure commences
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I would respectfully disagree with that statement.

 

All good, i beleive it was a misinterpretation of CAAP 257-EX-01 – Approval to conduct low visibility operations and CAAP 257-EX-02 – Conduct of practice autoland operations in that they refered to airlines making specific SOPs for the conduct of autolanding if approved by CASA. External to flight sim so far i have conducted my BAK which has given me an overview of the documentation, however being that this us my first time looking at such documents ive misinterpreted them...

 

All said i have found the CIVIL AVIATION ACT 1988 CIVIL AVIATION REGULATIONS DIRECTION UNDER CAR 215(3) which Operating procedures are to be based off... so i have learnt a fair bit regulatory wise from this

 

All said, i didnt know that a lot came down to manufactures specifications and procedures and that the documentation is dependent on the aircraft used, but that could be as my formal training was quite a while ago now, so thank you for the heads up

 

As for the experience, thats what im trying to develop with touch and goes, even then ive found everyone has a different time and way of flaring, and manual flight, following the same basic principles as outlined by regulations and manufacturers specs.

 

Thank you very much for the help, its much appreciated. .. now for some more touch and goes then step up through each cat ;-)

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Fantastic explanations by Haydn! Thanks a lot for that :)

It seems to be true that every pilot has his own take on this issue, as you say.

 

Sam: If you fly in FSX, my personal recommendation is the following:

 

- If you intend to do an Autoland, you already know of course, AP on throughout the approach and landing.

- If you intend to land manually, disengage the AP before descending below 1000 feet. This will give you time to "get a feel" for the plane. I don't think it's a good idea to take over 200 feet above the runway, even if it's legally permitted.

- If you feel more confident, disconnect the AP much earlier and fly the whole approach by hand, you'll notice this to be much more challenging (and satisfying).

 

Also note that, regarding ILSs and FSX, within the simulator EVERY ILS is treated in exactly the same way, meaning you can basically fly a CAT III approach if you wish to.

 

I found an old thread that might be of interest to you:

http://www.avsim.com/topic/440291-cat-iii-instructional-video/

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All good, i beleive it was a misinterpretation of CAAP 257-EX-01 – Approval to conduct low visibility operations and CAAP 257-EX-02 – Conduct of practice autoland operations in that they refered to airlines making specific SOPs for the conduct of autolanding if approved by CASA. External to flight sim so far i have conducted my BAK which has given me an overview of the documentation, however being that this us my first time looking at such documents ive misinterpreted them...

Sam - I see where the confusion has come from. Directly from CASA's website:

Our Civil Aviation Advisory Publications (CAAPs) provide guidance and explanatory information about the meaning of certain requirements in the Civil Aviation Regulations 1988 (CAR). They may also describe methods to help you comply with a CAR requirement in a manner that would be acceptable to an authorised person or CASA.

CAAPs are advisory; they should always be read in conjunction with the referenced CAR.

 

CAAPs are basically not regulations but if you choose not to follow it and have an incident, you'll have a lot to answer for. You'll see that to conduct Low Visibility Operations (anything less than CAT I minima) as per CAAP EX-01, it requires a specific exemption issued by CASA and an operator would need to submit the application for a LVO exemption based on the criteria spelled out in that document (intent to train and qualify crew, etc). The document lays out the criteria that would need to be addressed (as I stated previously: risk mitigation) to be considered for an exemption. Part of that would include spelling out how the operator intends to ensure flight crew proficiency which is where CAAP EX-02 comes into play. This document provides guidance to operators on what procedures they would need to develop to ensure flight crew proficiency. It's important to note that proficiency is relevant in more than just autoland procedures - under Australian regulations if you haven't completed an ILS (practice or real) within each 90 days and you're faced with the prospect of needing to do one to safely land - you legally can't!

 

You are quite correct that CAR 215 provides the regulatory guidance for what CASA requires operators to place in an operations manual. This allows operators a guide to build the manual for approval so they're not left guessing. Why is so much of it based on manufacturer specifications? Will that's simply because they are the ones who have the data necessary to determine what the aircraft is actually capable of. An airline that flies 737's, 767's and 747's would have a different operations manual for each aircraft. So if you were writing a manual for a new aircraft the best place to start to collect the information CASA requires for an operations manual would be the person who has all that information - the manufacturer. 

 

I certainly was not attacking your experience levels, everyone here has different levels of knowledge and the only way to get answers is by asking questions. I was more reinforcing that these a hugely complex aircraft, that despite flying the same way as smaller aircraft, require a lot of training and experience to fly safely outside of a simulator environment. And you're most welcome!

 

Jaime - No problems! It's not so much a "take" as it is technique or knowing from experience. You could fly into the same airport on the same day 5 times and it could be different in 5 different ways. Flying is an extremely dynamic and fluid environment - no two flights are the same!  As you stated in your third point a smooth landing in trying conditions is far more satisfying than a smooth landing in good conditions where it is more or less expected. A particular technique as long as it doesn't contravene regulations or operations manual is not wrong.... just different. The same as two people driving a car won't drive it in exactly the same way even though they're still complying with the road rules and limitations of the car. 

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Thanks heaps mate! Hopefully flying this complicated beast more, will help me when i do eventually go for a PPL ;-)

 

I took the ngx for a spin last night, did two manual circuits, one mqnual cat I a semi auto CAT II and a CAT III was a lot of fun, i do agree that it may be an idea to go manual at 1000ft AGL until uve had more practice, as i was going manual during the CAT II at DH (167 FT at the aerodrome) however the challenge was a lot of fun

 

"The only bad question, is the one not asked" ;-)

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"The only bad question, is the one not asked" ;-)

Absolutely! And you're most welcome. Best of luck with the PPL - if you elect to continue past that you will develop a love/hate relationship with the law docs for your exams (definitely speaking from experience there!!! haha)

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I took the ngx for a spin last night, did two manual circuits, one mqnual cat I a semi auto CAT II and a CAT III was a lot of fun, i do agree that it may be an idea to go manual at 1000ft AGL until uve had more practice

 

Absolutely! Touch & Go practice is the best way to acquire a feel for the aircraft! Real pilots do it, why would Sim pilots not do the same?.

 

Here's a video I did on Touch & Goes. It's for the 777, but you can apply it to the 737 minding some differences.

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