Shannon ILS

oscarBravo

Flying from Heathrow to Shannon on the red-eye this morning, we had two missed approaches due to low cloud over the airport. The pilot informed us that procedures prohibited another attempt after two missed approaches, and he had to divert to Dublin. We refueled in Dublin, he filed a flight plan, and we got back to Shannon as quickly as he could manage. There was still low cloud, but we made it - I would say only just.

The jarring part of the episode for me was that he also told us the reason the low cloud was a problem was because the ILS¹ was turned off for testing. Why the hell would an airport turn off an ILS in low visibility conditions when flights were due? Couldn't they test it at like midnight or something?

Anyone got any theories or insights? I don't have a problem with the PIC's handing of the situation - better safe than sorry - but it's annoying that the conditions that existed seem to have been avoidable. Especially after getting up at bloody 4am for the flight, and only getting to Shannon after 10am.



¹ He didn't say "ILS", he said "the equipment that allows low-visibility landings" - I drew my own conclusions.

highlydebased

Probably because 24 is having a new ILS installed. Just coincidental that it had to be turned off in this weather. VOR could have been off too

FlutterinBantam

Ils turned off for testing.

not being flippant ,but I'm sure you would rather that piece of avionic equipment was properly tested before being switched on and declared operationally safe???

You were unlucky that the cloud base was so low.Apparently there were several diversions from Snn this a.m.

On a clear day you would never have known.:)

oscarBravo

FlutterinBantam wrote:

not being flippant ,but I'm sure you would rather that piece of avionic equipment was properly tested before being switched on and declared operationally safe???

Absolutely. So test the goddamn thing when there isn't a redeye flight due in from Heathrow.

There's only one reason people get up at 4am to catch a flight to another country (especially when there are as many flights as there are from Heathrow to Ireland), and that's because they have someplace they need to be. I had to spend the time on the ramp in Dublin ringing around to cancel a meeting that had been organised several weeks in advance, because I couldn't be sure I'd make it in time.

PhoenixRising

It's out of service until early August. They didn't just happen to turn it off for your flight. It's been gone for a few weeks already.

oscarBravo

Useful to know, thanks. I didn't imagine they checked the passenger manifest and knocked it off 'cos I was flying in.

I'll be scheduling my next trip to arrive in Monday evening instead of Tuesday first thing - doesn't exactly suit my plans in London, but at least I'll be able to plan for work on Tuesday.

It also means that what the pilot told us doesn't quite gel with what's actually going on.

PhoenixRising

oscarBravo wrote:

It also means that what the pilot told us doesn't quite gel with what's actually going on.

Sounds like he explained the situation perfectly. The ILS in Shannon is off the air until August. Aircraft have to fly a different type of approach which is not as accurate and thus has higher minima. Most airlines have a policy of two attempts and then divert - no exceptions.

therecklessone

oscarBravo wrote:

Absolutely. So test the goddamn thing when there isn't a redeye flight due in from Heathrow.

The new equipment can't be certified as operational until the testing is complete, IIRC the testing requires the ILS to radiate for 30 full days and also needs calibration before it can be used operationally.

Poor timing is all.

oscarBravo

PhoenixRising wrote:

Sounds like he explained the situation perfectly. The ILS in Shannon is off the air until August.

Right, but he didn't explain that. He said it was "turned off for testing" - to which one's response is, "so turn it on, already!" If he had said "Shannon is operating without ILS for several weeks" - that would have been explaining the situation perfectly.

PhoenixRising wrote:

Aircraft have to fly a different type of approach which is not as accurate and thus has higher minima. Most airlines have a policy of two attempts and then divert - no exceptions.

No issue with that - I've already said I had no problem with his handling of it. I don't expect him to compromise passenger safety to suit my timetable. I'm a little surprised at an international airport (at sea level on the Atlantic coast) operating without ILS for any period of time, is all.

jmayo

oscarBravo wrote:

Right, but he didn't explain that. He said it was "turned off for testing" - to which one's response is, "so turn it on, already!" If he had said "Shannon is operating without ILS for several weeks" - that would have been explaining the situation perfectly. No issue with that - I've already said I had no problem with his handling of it. I don't expect him to compromise passenger safety to suit my timetable. I'm a little surprised at an international airport (at sea level on the Atlantic coast) operating without ILS for any period of time, is all.

Maybe the pilot had other things to think about rather than go through the dates and history of the ILS outage for testing.
Otherwise saomebody would be on here complaining that the pilot spent 5 minutes speaking all technical, rather than get them on the ground somewhere.
It is unfortunate that it happened to be cloudy when you arrived at Shannon.
Maybe God was trying to tell you something?

You would be surprised what airports do or don't have working.
Could be worse it could be Knock airport without ILS.

oscarBravo

jmayo wrote:

Maybe the pilot had other things to think about rather than go through the dates and history of the ILS outage for testing.
Otherwise saomebody would be on here complaining that the pilot spent 5 minutes speaking all technical, rather than get them on the ground somewhere.

ffs. Are you arguing for the sake of it?

jmayo wrote:

It is unfortunate that it happened to be cloudy when you arrived at Shannon.
Maybe God was trying to tell you something?

Maybe God was trying to tell Globespan's passengers that they weren't supposed to leave New York? I don't remember anyone smacking them down when they complained about their delays.

jmayo wrote:

You would be surprised what airports do or don't have working.
Could be worse it could be Knock airport without ILS.

Knock Airport does have ILS.

PhoenixRising

oscarBravo wrote:

Right, but he didn't explain that. He said it was "turned off for testing" - to which one's response is, "so turn it on, already!" If he had said "Shannon is operating without ILS for several weeks" - that would have been explaining the situation perfectly.

The NOTAM for Shannon re the ILS says the following:

Q) EISN/QILAS/I/NBO/A/000/999/5242N00855W005
FROM 07/06/27 08:00 TO 07/08/02 11:00 A1035/07
E) ILS LLZ RWY 24 ID ISW 109.5MHZ U/S
REF AIRAC SUP 23/07
E) RWY 24 LLZ.
RADIATING ON TEST. DO NOT USE.
E) RWY 24 GLIDE PATH RADIATING ON TEST.
DO NOT USE.

Equipment on test is equivalent to being turned off from a pilots point of view. No navigation aid can be used by aircraft while it is on test. Whether he said 'turned off' or 'on test' is just semantics. He wasn't telling porkies and probably had other things on his mind in a dynamic situation with poor weather, 2 go-arounds, low fuel , and preparation for the diversion. Cut the guy some slack on the words he used to explain the situation. He wasn't lying to you!

therecklessone

oscarBravo wrote:

I'm a little surprised at an international airport (at sea level on the Atlantic coast) operating without ILS for any period of time, is all.

If you want them to replace the old ILS at any stage it necessitates a period without a working ILS on rwy 24. You'd accept that there's a need at some point for a replacement ILS? You can't put a new one while having the old one radiating, therefore there's a period of no ILS, then a period of ILS radiating on test.

As I explained above, the new ILS needs to radiate for a period of 30 days before it can be certified.

TBH, if anyone's arguing for the sake of it it appears to be yourself. There's plenty of reasons for the crew not going into technical detail while giving their explanation to the passengers, work load associated with a couple of go-arounds plus a divert to their alternate being the main one.

hobie

had a very similar problem in the old 747 days ..... two early morning passes and then off to Dublin .... Lingus popped us into a cab and away we went to Shannon ....

Just as we finally arrived in shannon, guess what we saw landing ......

a great big 747 from Dublin, enroute back to the States ....

jmayo

oscarBravo wrote:

ffs. Are you arguing for the sake of it? Maybe God was trying to tell Globespan's passengers that they weren't supposed to leave New York? I don't remember anyone smacking them down when they complained about their delays. Knock Airport does have ILS.

No, I am not arguing for sake of it.
But as PhoenixRising said, give the pilot a break. He had a lot going on.
You cannot compare the Globespan cock up with what you experienced.
Yes I know Knock has ILS but it gets a lot of fog and low cloud so if it is out then you have more problems. It would be interesting to check how many diversions have there been form Knock because of weather.

I have been delayed for 3.5 hours on aircraft in Dublin plus 1 hour Shannon on trans Atlantic and ended up missing three connections, so I know it is not nice when your plans fall apart, but cut the pilot some slack. Have a go at the airport authority, it's where the problems lie.

highlydebased

-Dublin had its ILS replaced not so long ago. The iLS for 28 was off the air for quite some time. As far as I know aircraft were offered a VOR DME instead.

If the pilot had said Shannon is without ILS for a few weeks, chances are most the pax would not have known what he was on about. From that viewpoint the explanation he gave was adequate.

FlutterinBantam

Replacing an ILS is not a switch on /off procedure.

The new system has to be calibrated by a specialised aircraft flying numerous approaches to verify the acuracy of any reading from the ground.

Only after exhaustive testing is the system passed as operationally sound.

Used to be a HS125 doing the "measuring procedure".

safety is Paramount.

highlydebased

They have a King Air doing it at the moment I gather

FlutterinBantam

There ya go.. as I said..

beech king...

Sponge Bob

Mick O Leary complained about the old ILS .

It was configured as a gently sloping cone at variance with the steep angle at which ryanair descends so they have bought a new ILS that will almost bring the plane in vertically to keep Ryanair happy .

The power of the market .

FlutterinBantam

Cmon... I know FR com in hard and fast but .. thats a bit over the top

oscarBravo

I suppose I should chime in here now that I've finally managed to get some sleep.

I never suggested that the pilot give a detailed technical explanation, as some people here seem to think I did. If he'd said that the ILS was out of commission for a few weeks while it was being replaced, I would have known exactly what was going on. Now I know - thank you to those who filled me in.

(As an aside, I hate it when people reply to what they thought I meant, instead of to what I actually said.)

jmayo

oscarBravo wrote:

I suppose I should chime in here now that I've finally managed to get some sleep.

I never suggested that the pilot give a detailed technical explanation, as some people here seem to think I did. If he'd said that the ILS was out of commission for a few weeks while it was being replaced, I would have known exactly what was going on. Now I know - thank you to those who filled me in.

(As an aside, I hate it when people reply to what they thought I meant, instead of to what I actually said.)

oscarBravo you are forgetting one important point.
How many people on board know what ILS is and what it means when it is not functioning? How many would want a technical explanation?
I bet most people wanted to know when and where they were going to land and how much fuel was left.

Also most of us posters aren't mind readers BTW.
And the beauty of the english language is that you can say one thing and mean something else.

oscarBravo

jmayo wrote:

oscarBravo you are forgetting one important point.
How many people on board know what ILS is and what it means when it is not functioning? How many would want a technical explanation?

Will you do me one small favour? Read my posts before you reply to them.

kthxbye

jmayo wrote:

I bet most people wanted to know when and where they were going to land and how much fuel was left.

Guess what? He told us when and where we were going to land. He didn't mention fuel, but I guess most people know there's enough fuel on board to handle situations like that.

jmayo wrote:

Also most of us posters aren't mind readers BTW.
And the beauty of the english language is that you can say one thing and mean something else.

Can't you see the contradiction in those two statements? If you can't read my mind, a safe assumption is that I mean what I say.

pclancy

Can someone explain the cone ILS descent? Does that really exist? I thought all ILS descents were a simple slope from the threshold to 15-20 miles out, not stepped or shaped in any way? Also how the hell would Ryanair get preference over the other airlines using shannon? Are things that bad down there business-wise that they boy to MOLs wishes?

therecklessone

pclancy wrote:

Can someone explain the cone ILS descent? Does that really exist? I thought all ILS descents were a simple slope from the threshold to 15-20 miles out, not stepped or shaped in any way? Also how the hell would Ryanair get preference over the other airlines using shannon? Are things that bad down there business-wise that they boy to MOLs wishes?

Switch on your sarcasm detector.

therecklessone

therecklessone wrote:

IIRC the testing requires the ILS to radiate for 30 full days

Just to clarify, this is a requirement for the ILS to be certified for Cat II operations. The ILS must be radiated for a cumulative total of 30 days without system failure before it can be passed for Cat II ops.

Sponge Bob

how does it 'radiate' when its switched off ???

pclancy

therecklessone wrote:

Switch on your sarcasm detector.

Roger that.