Somewhat off-topic question from SLF: Do I read this right that in a CAT3 auto-land, another airplane lining up distorts the signal enough that it can become exciting? I am not 100% clear how the system works once on the ground - is the sender at the touch down end of the runway and therefore, a hunk of metal lining up is essentially the equivalent of a truck right in front of my favorite radio station?

Thanks

@FC,

Yes, you see the loc-signal swing from left to right and back. Most of the time you see it when somebody crosses the signal before you (when you are on final) but it can happen when you are on the ground as well.

To operate under Cat3 you still use the same ILS as with Cat1, but with many more requirements:
-redundancies in aircraft systems (a.o. multiple autopilots; multiple and separate electrics and hydraulics)
-redundancies in ground based systems (o.a. backup power; failure monitoring)
-last but not least: LVP (low visibility procedures) for ground movements. Somebody crossing the LOCantenae can easily disturb the signal; runway incursions by vehicles occur more easily. Therefore there are a.o. restrictions on the amount of movements and extra protection areas around antennae
LVP have several phases and as vis goes down, the requirements go up.
I'm just a pilot, perhaps a controller can give you accurate info

Now the tricky point: while modern aircraft can land in almost any vis, the airports effectively lock up during low vis; capacity is decimated. Hence airports very quickly phase back their lvp when weather improves and there you are: doing auto lands under marginal weather without the protections, but with the risk for a swinging loc-signal.
For me these are the most risky autolands, especially the auto-rollout.

From a previous post:
"For modern autoflight systems, as on the B777, with filtered path definition, even if some type of transient LOC multipath interference should occur (e.g., with no LVP in place, or failed LVPs), and even if at low speed, that magnitude of apparent lateral displacement would not typically be expected. We'll likely just need to wait for the incident review findings to learn more about this one. ...as we continue to hope for early and widespread implemmentation of GLS, where multipath and related LVPs are largely irrelevant."

That means the airplane is essentially buffered against wild swings back and forth.

But let's not let that bother anybody - let the games begin.

Of course, if no one is doing what they are trained to do, like watching, then the game is anyone's call.

In CAT3 conditions the Captain does the landing. FOs have to be encouraged to do a practice autoland, they prefer manual as it counts towards their overall experience, measured in sectors,hours and landings.

If there was another crew on board, AND they were sat on the flight deck, then they will be asked to report what they saw.

"Practice" autolands are illegal for FOs. Who is minding the store? Think about this! Where does training permit this?

"practice auto lands" are from the times the simulators were not capable enough and a pilot had to keep himself current - and CAT3 approved - with couple (three?) of "practice auto lands" en route every year.
Nowadays the FFS sims are good enough to keep the pilots current with the minimum required number of auto lands per year in the sim. The training dept will assure the minimum nr is met.

Tech log entry #01.

Autoland unsatisfactory.

so when they do, who is monitoring what? Think any program considering FO autolands needs to be at least conversant with the certification basis of the autoflight system, and how that impacts monitoring requirements of the crews. If you need the references, feel free to PM, or contact your friendly ACO :}.

re filtering, absolutely correct for the B777. The flightpath will not be affected by transients of the LLZ at the latter stages of the approach, at higher altitudes, it will be... Somewhat different to the B757/767 and even the B744.

Fact: SQ FOs do not do auto lands as PF, either in actual or practice. ALL auto lands are done with Captain as PF.

Tech log response #01.

Autoland not fitted to this aircraft. :E

Really ETOPS 777???? Are you starting to fabricate incidents to prove your point??? Yes agreed every airline has its shares of incidents, but I must admit, SIA is well known for brushing incidents under the carpet.

it is true.

Dear Mr CargoJock,

It is clearly stated that the FO flying sector is at the sole discretion of the commander. Whatever stated are only guidelines.

If the captain is confident that the FO is able to handle the weather condition, he can actually allows the FO the fly in conditions above the recommended guidelines.

If you look at it more carefully, the initial SO training stated very clearly that it is a LIMIT and not guidelines. Once they attain sufficient experience, it will solely be at the training captain's discretion, that is back to the FO flying guidelines.

We are given ample opportunities to hone our manual flying skills and in my opinion, whatever was stated above is not a true representation of the SQ culture.

Do correct me if I am wrong.

Flap 10.

not to mentioned about a tailstrike on CX..

Cathay Pacific Airways - Hong Kong's de facto flag carrier and largest air transportation company - has grounded a Captain and First Officer pending an investigation into an Airbus Industrie A340-300 tailstrike incident at Auckland Airport.

The plane, carrying 145 passengers (59.6% load factor), left the ground too steeply as it took off. Passengers alerted the cabin crew about a shudder that they all felt after takeoff. Cabin crew alerted the junior Captain - one of the airline's first Chinese captains to be promoted to such a rank.

The Captain decided to radio to the air transportation company's headquarters to enquire about what to do and it was decided that the aircraft should continue as normal to its destination - Hong Kong.

A pilot interviewed by The Dominion Post of New Zealand said, "With something as serious as a tail strike, you would normally go straight back to the airport. It is standard procedure."

It was only until CX108 landed at its destination that the damage was discovered.

The above was found on airliners.net

Don't get me wrong. What I want to say was it does happens to anyone and any company.

The LOC Antenna and the transmitted signal would have been in front of the landing 777. Not behind.

Actually ETOPS 777 you're just re-posting an old news article that is full of misinformation of an incident that happened many, many years ago :ugh: What exactly was your point??? I thought I clearly stated in my previous post that no airline is immune to incidents. But if you're here to compare incidents between SIA and other airlines, I am afraid it would be no competition.

And it's not only other aircraft that can distort the LOC signal. Even a vehicle on a perimeter road can have an effect. That is why it is so important to understand that a 'practice' autoland, when LVP is not in force, carries with it a far greater risk than when the approach is protected. The risk during rollout can be somewhat mitigated by briefing and disconnecting the autopilot very soon after touchdown.

Where to begin
 

Not sure the LOC GS signal stabilization works on the ground roll as it reverts to ATT and TRK/HDG .

Etops777 you are coming across as disingenuous. You are obviously upset at your airline being slandered but you then slander another. Not too cool.

When has the media ever understood pilots and flying airplanes ?

All I can hope is that we as an industry figure out what went wrong so we can all learn from this unfortunate incident.

Why is it that people who don't work for SIA claim to know so much about what goes on in SIA? Every carrier will try to keep incidents 'in house', including CX. I very much doubt if the incident rate in SIA is any worse than most major carriers. Jealousy is a dreadful thing.

Regarding FOs doing practice autolands, don't confuse this with doing a practice CatII/III approach, it is only an autoland carried out in Cat I or better. In the event of captain incapacitation an autoland may well be the best way for the now over worked, single crew FO to go. If SIA have stopped even practice autolands for FOs then they have changed their policy.