Low Visibility Procedures

On top of all this, it's good to note that I don't believe CATIIIc mins are used for any commercial flights...anywhere. It's autoland only, and since It's still a fledgling system the only times it's used are for experimental autolands. Someone correct me if I'm wrong.

Nothing experimental about it. The reason for *not* using Cat.IIIC is very simple - how do you propose to get off the runway if you can't see anything in front of you?? ^_^ You'd land and block the runway. :ph34r: The only time that might not apply is if you have a FLIR system that enables you to see something.

 

Several airlines used to operate Cat.IIIC certified aircraft, but after the practical problem of getting off the runway afterwards, they don't bother as it is additional expense, but the equipment is capable of it. They usually certify to Cat.IIIB and leave it at that.

 

Best regards,

Robin.

Just as Robin said, landing is the easy part as far as CAT IIIc is concerned. And in some situations, lets tell that you could do it (provided the runway can stay blocked for a while, say if you were so low on fuel diverting to nearest suitable alternate is out of question, and no other plane is expected to land).

 

However, there is this problem of getting out of the runway, but that can be done as well, for example it is relatively simple to program a robot to follow a line or something. There is very little reason a tug could not be programmed to attach itself to an airliner (that is sitting on a centerline of the runway) and tow it on a predetermined route.

 

The real problem, however is, that rescue vehicles must be able to get to the airplane should something happen. Your landing gear may collapse (as has happened recently to an A310 in Bratislava), or you may skid off the runway for a different reason.

Emergency vehicles, however, are simply not capable of finding you if they cant see 5 meters in front of themselves.

There is very little reason a tug could not be programmed to attach itself to an airliner (that is sitting on a centerline of the runway) and tow it on a predetermined route.

 

Good points.

 

It doesn't even need to be that complex, either. A tug is relatively low to the ground and the rampie towing it could quite easily see the taxi lines and pavement. The bigger issue at that point is liability. Human tow or robot, the airline would want people walking under the wings to ensure you don't smack them with anything. If the tow operator couldn't see the people under the wings, it's unlikely they'd agree to do it. So, even though it's a cool concept, it's almost more cost and time effective to just divert.

They were thinking about similar stuff 20 years ago. Back then the topic was undercarriage/gear. It weighs tons of useless (besides TO/APP) mass and takes a lot of space. The idea was to mount the aircraft on a skid for takeoff and even "catch" it during landing. But the well known old story kicked in... "What if something unpredictable happens?"

I would not label that idea as complete nonsense. The "What if..." can be used for every automatization but look at modern airliners... full of computers which do a great job. Military aircraft are allready a step beyond. They are aerodynamically unstable to maximize manoeuver (i bet it's misspelled ) performance. Without an assisting computer a pilot would have a very hard job to simply keep it in the air.

 

Regards

Hirschi

They were thinking about similar stuff 20 years ago. Back then the topic was undercarriage/gear. It weighs tons of useless (besides TO/APP) mass and takes a lot of space. The idea was to mount the aircraft on a skid for takeoff and even "catch" it during landing. But the well known old story kicked in... "What if something unpredictable happens?"

I would not label that idea as complete nonsense. The "What if..." can be used for every automatization but look at modern airliners... full of computers which do a great job. Military aircraft are allready a step beyond. They are aerodynamically unstable to maximize manoeuver (i bet it's misspelled ) performance. Without an assisting computer a pilot would have a very hard job to simply keep it in the air.

 

Regards

Hirschi

 

A couple of lucky or well aimed cannon shells and you're done! No chance any more of arriving back at base full of holes!

A couple of lucky or well aimed cannon shells and you're done! No chance any more of arriving back at base full of holes!

 

Thats so true. Two nozzles, two seats and two backups of every vital system was a very good idea as long as it lasted. Reminds me of my service at military radar. F-16 out of Spangdahlem (ETAD) did some TRA work and suddenly wanted a handover to ATC for RTB although the playtime left was still about 30 minutes. He didn't say the reason and we found out via ATC he was in severe trouble due to engine problems.

About 10 NM on final he crashed into a field and the saddest thing, he didn't shot out (we will never know why). That fatality was caused, probably among other things, due to the lack of a 2nd engine.

A well placed EMP will cause more trouble to modern fighter a/c than a bullet, i'm afraid.

 

Regards

Hirschi

That fatality was caused, probably among other things, due to the lack of a 2nd engine.

Tell that to all the F-18 drivers who lost their jets after a single engine failure. The F-16 has above average reliability. The two vs. one engine argument is long dead. All two engines do is double the chance of failure.

 

I'd suggest the reason he didn't eject was the reason he crashed short of the field.

 

Best regards,

Robin.

You are surely right. Loss of aircraft due to engine malfunction is not that factor for the F-16. But thats design. High engine reliability and a pretty good (for a fighter a/c) glider. But if a birdstrike occurs or a compressor stall at low altitude its always a bail out. I don't know much about the F-18 story but i'm pretty sure it's a design thing, too, but this time as a disadvantage. Maybe the loss of one engine or a certain engine hurt the avionics hard (generator, hydraulics) so it becomes unflyable. Per simple mathematics and probabilities, 2 engines are always better than one.

If the chance for birdstrike on one engine is 1%, than it is for the 2nd engine at the same time 0,01%. But I never would tell that Mr. "Sully" Sullenberger and his incredible FO Jeffrey Skiles (every commentary seems to forget him). Thats the problem with statistics.

We puzzled a lot over the reason for not ejecting. I don't understand what you mean with

I'd suggest the reason he didn't eject was the reason he crashed short of the field.

. The Martin Baker is absolutely independent of every aircraft system afaik. A forgotten pin maybe (oh I don't want to think about that). The replays of the radar showed a normal approach, not even a short one. But thats all guesswork. I don't know what happened in the aircraft. I was only shocked, that he didn't bail out because after "Pull green apple!" is "Eject!" that phrase where pilots react to in the middle of a deep sleep.

 

Regards

Hirschi

Yep an aircraft could have complete electrical failure but the Martin Baker or ACESII seats can still function, (F-16 does not use the Baker seats BTW, its the ACES seat). Amazing thing though, if a fighter flies fast enough, it does not need two wings.

 

If you have enough thrust, nothing needs two wings. See: Saturn V Rocket.

How come official VENICE LIPZ charts (JeppView 3.7.4.0) do not provide more clearly information on ILS CAT III? There is RVR = 300 m for ILS CAT II clearly provided by the chart.

 

Geir

How come official VENICE LIPZ charts (JeppView 3.7.4.0) do not provide more clearly information on ILS CAT III? There is RVR = 300 m for ILS CAT II clearly provided by the chart.

 

Geir

Because it's a CAT II airport.

Because it's a CAT II airport.

 

This is quite tricky to get. Their company allows them to go RVR = 200 m, but official charts restrict RVR to 300 m . I thought it was the other way....never "lower" than official charts.

 

Geir

This is quite tricky to get. Their company allows them to go RVR = 200 m, but official charts restrict RVR to 300 m . I thought it was the other way....never "lower" than official charts.

 

Geir

Technically speaking Tessera is a Cat II/III. But the airport is frequently fog bound in the cooler months and the approach lighting is Cat II. So in practice it's always Cat II.