G/S inop on ILS approach.... can you continue?

[palgia]

Quick question...

I have always thought that if you're on an ILS, and the Glideslope fails while you are still above the LOC MDA, you can revert back to a LOC approach and fly that approach accordingly (after notifying ATC of the failure...)

This can be done provided you have taken the appropriate steps to be able to identify the LOC MAP. (ie. starting time over LOM)

Does anyone disagree with this?

I just met a very experienced instructor yesterday who told me that if the GS fails on the approach, you are obligated to go missed and then eventually get re-vectored to the LOC only approach.

I looked it up in the books but I could not find anything that specifically said you HAD to go missed if a GS failed. I only found something that said you HAD to notify ATC of the failure (although I personally feel that this is not a priority unless there something ATC can do to help you, or if the failure can preclude your ability to comply with their instructions).

I am interested in the "by-the-book" answer as it would apply to a flight being operated under FAA part 91. What any one of us would "actually" do in this situation would depend on a myriad of factors (familiarity with approach, wx at the field, fuel situation, workload at the time of failure, how well the LOC IAP had been briefed, company SOPs...well, maybe those should come first:E )

Thanks for your input.

palgia:ok:

[777300ER]

So many accidents have been caused by poorly flown non-precision approaches. The idea that you could lose the GS and instantly revert to an unbriefed LOC only approach is in my opinion a bad one. The safest thing is to conduct a G/A, brief the LOC procedure accordingly, then conduct the approach.

[BlueEagle]

I believe a properly briefed ILS approach should include the possibility of a lost GS together with the new minima to be applied and in most companies a minimum height is stipulated before which a transition to a LOC Only approach can be made and below that height a GA is mandatory. Each company will have its own procedure and this may exclude any change at all and require an immediate GA regardless of height.

[OzExpat]

I don't know what FAR Part 91 has to say about this situation but I'd be very surprised if it was much different to CAR Part 91 here. Reversion to Localizer approach is permitted here. Indeed, I've experienced GP failure a few times and, having already briefed the GP failure procedure and knowing that the ceiling and vis would be acceptable, continued the approach.

On each occasion, I was already configured and established on the 3-degree approach at the time of the failure. Thus, by using a cross reference to the DME/Altitude table on the chart, I was able to maintain the approach path to the MDA and land normally (or about as normal as things are for me! ;) )

[Bumz_Rush]

A good approach brief should include the expected unexpected...and loss of GP should be one of these.....so the alternate descent profile, and the new limits knows, and accessable.
I have had several change of approach in recent years.
Not including the last minute "atis" with the news that the approach is LOC only.
When I did my UK CAA IRE ride, it was pointed out that this was a normal approach, and subject to the briefed approach, and aircraft set up correct, then NO problem.
Bumz

[Backtrack]

The 'by-the-book' answer is yes, you can continue the approach in the circumstances you described. (Well, it is in JAR-OPS).

Airmanship, however, may require something different.

[BEagle]

Not so long ago, in perfect visual conditions, an airliner was flying an ILS approach when the GS failed. The FO carried out a missed approach "Because that's what the company SOP said", then faffed about re-briefing for a non-precision approach.

That he was incapable of converting to visual at a perfectly safe height in ideal conditions speaks volumes about the confict between slavish adherance to SOPs and sensible airmanship which appears to be the norm these days.

[keithl]

Agree with all previous, the book answer is, "Yes". But I've just gone through a tedious exercise correcting our publications to remove "LOC" and replace with "LLZ" as it was causing confusion.
I know there aren't many LOCator beacons around, but as I've said in other threads: "Pedantry reduces ambiguity"!

[GlueBall]

BEagle: When you're visual, IFR minimums no longer apply and IFR call-outs revert to visual call-outs.

If you're in VMC and you make a go-around when the G/S fails "because the SOPs say so" then you are using neither common sense nor practical reality.

SOPs do not constrain you from exercising good judgement and good common sense.

If your plane's on fire, are you going to delay the landing if necessary in order to complete all the applicable checklists...?

:confused:

[BEagle]

GlueBall - agree entirely. The turkey really believed that he had to go-around because he hadn't briefed for a visual approach. Perhaps his Captain should have told him not to be an idiot and directed him to fly a visual approach. But huggy-fluffy CRM people wouldn't like that, no doubt - conflict on the flight deck - WAAAAH, mummy, help.

[palgia]

Thanks to everyone for your input.

I agree with all the views you expressed. I have been taught this way and have been teaching this way for several years. I just wanted to make sure I wasn't missing something.

Thanks again for your help,

palgia:ok:

[FE Hoppy]

Kiethl
I fear you may have acted in haste as I believe the decision to use LOC or LLZ is still up for grabs and as the EFIS manufacturers are using LOC then that’s what we will standardise to eventually.

[alf5071h]

The safeguard of briefing alternatives can defend against any risks originating from late changes of plan or the additional hazard of the operation.
Whilst NPAs are 5 times more hazardous than precision approaches, it is unlikely that a G/S out approach is that extreme at an airport that has an ILS, but don’t forget the Zurich accident.
Basic procedures can add further safeguards; recall that in the original ILS LOC concept there were up to three markers enabling three independent checks of altitude / GS accuracy / distance. Most have been replaced by DME, but how many people use more than one DME cross check on an ILS (if at all). Remember the Air NZ ILS GS failure and the near CFIT event with a wide body jet in Rio (2 actually the second 777 had EGPWS).
Using Rad Alt for terrain awareness during an NPA is a safeguard (you should never see less than 250ft before MDA), but how many of us use Rad Alt for awareness on a Cat1 ILS although the terrain clearance is less?
Applying common sense requires judgment, but if one or other of these are flawed then the risks increase. Perhaps some operators recognise these weaknesses in modern operations and therefore mandate a GA and rebrief.
We are all safe enough until the first incident.

[keithl]

Hoppy, - take your point, and I think it comes down to the Approach Plates being written with "LLZ" and the Flight Systems (EFIS or earlier - I think even our old Nimrod had a LOC button, didn't it?) with "LOC". The manuals I write are just to do with Plates and Procedures, but I do agree that it needs to be resolved.

[OzExpat]

In this part of the world, any runway-aligned approach that uses DME includes a DME/Altitude tabulation. Makes it very easy to cross-check your profile every mile from the FAF (or FAP). Very helpful in avoiding CFIT risks.

Is this not standard in other parts of the world?

[chofuan]

How good are you with the briefing and how fast can you organize your cockpit for such an event are the keys to continue with your app legally and safely.
One mistake and your will be fired or making the headline in your local newspaper.

Common sense and CRM.