Foggy weather

[Maddie]

Hi, I flew into East Midlands this morning just before 9.00am, to me it seemed quite foggy with virtually no visibility.

I kept thinking we would break through the clouds at least a couple of minutes before touch-down but we didn't. We touched down then started to see a little bit around us but not much.

I have to take my hat off to the crew, despite all the training and instruments and computer back up etc., etc., it still must take nerves of steel to land in this type of weather. Thank you so much for getting me back safely.

My question, in aviation terms is, how bad was the fog this morning, did it just appear worse to us as SLF than it really was.

Many thanks for your replies.

[Dash8driver1312]

Cat 3 ILS conditions, autoland. First time you do it, it's interesting, but autoland first came in with the Trident decades ago. To be honest it is a non-event because you train to it on a regular basis and if there's any doubt in the equipment, you go somewhere with better visibility.

[west lakes]

This is just having crossed the threshold of 27 at EMA a few years ago.
I had driven past on the A423 about 30 minutes before this was taken it was dire
http://i225.photobucket.com/albums/dd161/west_lakes/emacat3_zps50825faf.jpg

100ft call
http://i225.photobucket.com/albums/dd161/west_lakes/1hundred_zpsf27f68d7.jpg

[strake]

This may be of interest:
http://www.youtube.com/watch?v=NZoRlFloO3w

[lomapaseo]

Great movie visuals :ok:

It's fun to visualize the lights coming at you as windows on buildings as you pass between them :bored:

[clunckdriver]

A good demo for the question asking SLF, but oh Lord, why the bloody music?

[Hotel Tango]

:) Yep agree, but the option to turn it off is there too ;)

[strake]

Wot? You mean there isn't orchestral backing on the flight deck for Cat 3 Autoland...!?

[Maddie]

Thank you for your replies, the more I see the more in awe I am. I am just glad I didn't know beforehand it was going to be so foggy.:*

[strake]

LookingForAJob: If that is the name of the piece, it is indeed an inspired choice...

[HEATHROW DIRECTOR]

Maddie.... It's not rocket science. As a pilot once explained to a nervous old lady who asked how he found his way around... there's a red light on the left wing and a green light on the right. I just fly between them.....

[Doors to Automatic]

As others have said it is a non-event - the only thing different is that the plane has two extra passengers on such a landing!

For real nerves of steel watch landings at places like Funchal and Leeds in gusting crosswinds!

[almost professional]

We went into low visibility procedures at about 8.30 Sunday morning, by 9.00 met visibility was 400M, and the visibility along the runway between 400/600M - arrivals all shooting CAT3 approaches - guess you were one of the Ryanairs?

[Maddie]

Yep, I came in from Dublin, we landed at 8.58 I think, 10 or 15 minutes early.

The crazy thing was that the cruise was really good - blue skies, isolated white clouds then we started to descend into the cloud and it went on and on.

I have been flying at least twice a week, most weeks, for many years now, but this was my first really foggy landing ever. My definition of 'really foggy' being you know you have touched down by sound not by sight.

As SLF with heightened awareness due to fear, I have to say, perversely, this experience has actually helped me.

[Hotel Tango]

I remember once coming into Brussels not knowing it was foggy. It was a foreign carrier and the FD had remained silent throughout the flight. I was therefore somewhat surprised when seconds after entering what I thought was the top of a stratus layer (at what I expected to be at about 2000-3000 feet or so) we touched down! It was shallow but dense.

[TightSlot]

I remember once being fascinated when sitting up on the jumpiest for landing. We overflow STN and looking vertically down. the area was foggy/misty but lights could be seen clearly. The same lights were invisible under thick fog on the approach. Looking vertically down was no problem - looking at the same thing on the glideslope was (of course) quite different!

[Basil]

An autoland, in limiting conditions, is, in some respects more difficult than a hand flown landing.
"How so?" you may ask.
Well, a lot of kit and computers must, demonstrably, be functioning before and during the approach; most importantly that the aircraft is accurately tracking the approach path in the vertical and horizontal planes - Glidepath (although we aren't gliding) and Localiser - and that it intends to flare at 20ft to 30ft above the runway.

When I flew my first automatic civil jet, the instructors' task was, amongst others, to ensure that we could fly the aircraft through the auto systems when our natural inclination was to disconnect and hand fly. Building confidence in the ability of the automatics takes training time - "What's it doing now?" being a common comment.

For a manual ILS (Instrument Landing System) approach the Decision Height is usually 200ft above touchdown. As systems, both ground and air, improved, the automatic landing DH went from 100ft to 50ft to 20ft to zero.

Using a Cat2 DH, of, say 100ft we'd call "50 above" at 150ft and "Decide!" at 100ft. If the aircraft could not be seen to be tracking correctly the next call would be "Go around." and, if tracking correctly, "Land."

Last time I flew with a Cat3C 0ft DH, we had a 75m visibility limit which was to permit us to taxi and the "Land." call was made at 1000ft above touchdown - but fear not - we still monitored the systems as before, ready to downgrade, increase the DH, land manually (vis permitting) or go around.

So you can see that there is a LOT more decision making in a very short time when monitoring an autoland in min vis conditions than hand flying to, say, 200ft.

Going on a bit, aren't I but, finally, when I began flying the RAF Argosy in 1968, we had a little leader cable aerial fitted on the nose which was to be used for automatic taxiing in zero vis. The ground cables have yet to be installed.

[togsdragracing]

Dumb question from SLF: does GPS play any part in auto-land nowadays?

[WHBM]

Cat 3 ILS conditions, autoland. First time you do it, it's interesting, but autoland first came in with the Trident decades ago.
I know being "first" can have many interpretations, but commonly accepted that Sud Caravelles operated by Air Inter in France, who were plagued by fog conditions at multiple points on their network, more so than in Britain, were the pioneers. First auto landing in development by a Caravelle was 29 September 1962, first commercial Cat 2 was 25 September 1964, first commercial Cat 3 was 2 March 1967, first commercial landing in real Cat 3 visibility 9 January 1969. All by Caravelles on the Paris-Lyon route, their number one domestic trunk at the time (business later mostly lost to the TGV train). All before the Trident I understand.

[DaveReidUK]

http://www.pprune.org/aviation-history-nostalgia/468456-first-autoland-commercial-service.html

[kenparry]

Dumb question from SLF: does GPS play any part in auto-land nowadays?
Not a dumb question, but no it does not. The guidance to the required accuracy comes from the ILS both in azimuth and vertically, with some input from the radio altimeter for the flare, and autothrottle for speed control.

[victor tango]

This discussion about Trident landing system reminds me of a delightful pipe smoking regular in my local back in the 90s.
He was on the team that designed and made it but always kept a low profile and shrugged it off as a sort of just another job ! Never bragged.

I asked him one night after work where I was having an AOG prob during that day. I said to him I couldn't understand why the MEL said AOG for a galley fan !
I thought is was a misprint.
He took a puff on his pipe, then said "I think you'll find that the same fan cools the radio rack" and this was a 747-SP ! I doubt if he'd ever seen one !
I bought him a pint.

[ExXB]

Not a dumb question, but no it does not. The guidance to the required accuracy comes from the ILS both in azimuth and vertically, with some input from the radio altimeter for the flare, and autothrottle for speed control.

Augmented GPS is being used at some airports ... Juneau, Alaska for example. Aircraft and airport both need to be equipped but it has reduced the number of diversions significantly.

From http://www.aiaa.org/uploadedFiles/About_AIAA/Press_Room/Videos/IAF-60th-Anniv-GPS-Nomination.pdf The trend today in the Next Generation Air Traffic Management System is toward an Area Navigation concept known as RNAV, with an even greater role for GPS. Area Navigation allows aircraft to fly user- preferred routes from waypoint to waypoint, where waypoints do not depend on ground infrastructure. The accuracy provided by space-based navigation systems increase safety in flight and on the ground. Terrain Awareness and Warning System performance is enhanced; GNSS-enabled ADS-B (Automatic Dependent Surveillance-Broadcast) significantly improves in-flight aircraft avoidance and ground operations (especially runway incursions). RNAV implementation at Juneau, Alaska has enabled 75% lower arrival minimums compared to Standard. In many cases, aircraft flying over data-sparse areas such as oceans have been able to safely reduce their separation between one another, allowing more aircraft to fly more favorable and efficient routes, saving time, fuel, and increasing cargo revenue. GPS also serves as an essential component for many other aviation systems, such as the Enhanced Ground Proximity Warning System that has proven successful in reducing the risk of Controlled Flight into Terrain, a major cause of many aircraft accidents in the past.

We could see this technology expand to other airports, but the airlines would need to agree to spend the money equipping their aircraft.