Ausatco

G'day Scott, Mike,

Over at Dunnunda we're having a discussion on landing clearances being issued on first contact with TWR, or maybe soon after, even though there may be a number of aircraft to use the runway before you get to it.

In Australia we don't do it.

One poster reports that it's done at CDG, France, and I know its done in the US, but I don't know if it's a standard procedure everywhere or at certain locations under certain conditions. Can you help us out, please:

Under what circumstances do you do this?

• VMC only?
• IMC?
• Do you do it when the runway is used for departures AND arrivals, or only when, say with parallel RWYs, you use one for departures and one for arrivals?
• Do you do it during crossing runway ops?
• Do you do it if the airport layout requires regular runway crossings?
• Are there specific conditions that must be met before you can do it?

Thanks in advance, guys

AA

FWA NATCA

AA,

To answer your questions about when we clear an aircraft to land it may help to understand what the runway set up is at the airport that I work at.

I work at FWA (http://fwa.natca.net ) which has 3 runways (5/23, 14/32, and 9/27) all of which intersect each other, the primary runways are 5/23 and 14/32. All aircraft (VFR and IFR) are sequenced by approach. Tower sequences any pattern traffic into the approach sequence without changing or affecting without coordination the sequence established by the approach control.

>Under what circumstances do you do this?

>VMC only?

>IMC?

Both, I can clear an aircraft to land as soon as it is switched by approach. Subsequent aircraft can be cleared to land on initial contact because they are sequenced by approach, but I still must monitor the final to ensure that the subsequent aircraft doesn't overtake the first aircraft.

Basically we are using "Anticipated Seperation". I anticipate that the first aircraft will be clear of the runway (large or heavies) before the next aircraft crosses the landing thresshold.

<Do you do it when the runway is used for departures AND arrivals, or only when, say with parallel RWYs, you use one for departures and one for arrivals

Since FWA does not have parellels we do it all the time.

>Do you do it during crossing runway ops?

Yes, but I must be sure that the first aircraft is through the intersection or if applicable is holding short of the intersection before the aircraft on the crossing runway crosses the landing thresshold.

>Do you do it if the airport layout requires regular runway crossings?

Yes, the majority of the operations at FWA require an aircraft that has landed to cross another runway to get to the ramps.

>Are there specific conditions that must be met before you can do it?

No, again we are using anticipated seperation. As the tower controller I have to monitor the final to ensure that seperation is maintained, even though approach is ultimately responsible for establishing the sequence and seperation on final.

If I have pattern traffic (VFR touch and go) I sequence this traffic in between the traffic that is sequenced to the runway by the approach control. Our SOP mandates that I do nothing that conflicts or affects the seperation on final unless I coordinate with the approach control.


Mike
NATCA FWA

Ausatco

Thanks Mike, much appreciated.

Nice website, too. Here's ours (unofficial).

Edited to add:

In a tower environment, we too are allowed to anticipate separation, but not to the extent you do.

That is, we can anticipate if we need to when we issue the clearance, but we don't issue the clearance until the aircraft is #1 to use the runway.

eg, if an arrival is tight behind a departure, a controller can issue the landing clearance before the standard is met, providing he is satisfied, in his judgement, that the standard WILL be met.

As a matter of interest, how far out (generally) are aircraft when they are transferred by approach to TWR? I'm trying to get an idea of the extent of your anticipation, such as how many movements might occur on the runway in the time between an aircraft getting its landing clearance and actually landing. Could there be, say 3 arrivals and you fire off a departure in each arrival gap, for a total of maybe 6 movements before the aircraft lands? (I don't mean pattern traffic here, you already answered that. I'm thinking IFR departures.)

Cheers

AA

Scott Voigt

What Mike says <G>....

There was a time a LONG time ago when we only cleared them one at a time and we moved past that <G>...

regards

Scott

Giles Wembley-Hogg

Hi Guys. I didn't want to add my thoughts to your Dunnunda thread as I have never flown in that part of the world and I didn't want to muddy the waters. I have flown in the US and to and from CDG and I would encourage you NOT to go down the route of giving landing clearances on first contact.

My reasoning behind this is that it gives the pilot no confidence that the ATCO has actually done anything to check that is, or will be, safe to land. When we get these sort of clearances there is often a chortle on the flightdeck and the feeling that "we are on our own again!"

If your problem is RT loading, can I suggest that instructing arriving aircraft from APP to "..report callsign only to TWR" works well, and having departing aircraft "... monitor TWR" is used successfully at a wide range of European airports.

If your problem is a 2.5nm arrival spacing being eroded quickly inside the marker/4DME (or your equivalent), then "... land after" or "... cleared to land after" work well in the UK with the added benefit of increasing the situational awareness of the preceding pilot.

Just my thoughts.

G W-H

Ausatco

Thanks Scott. Yes, necessity is the mother of invention.

Giles, re Concur. Many aircraft do report on final with callsign only, but equally, many embellish a bit, though it's usually pretty brief, as is our "ready" call for departures.

I think your second paragraph is quite relevant to the Dununda discussion!

Cheers

AA

FWA NATCA

AA,

Our local SOP dictates that all arrivals are switched to the tower prior to 3 miles from the runway.

If I have no other traffic that conflicts with the arrival, and the arrival will not violate another controllers or facilities airspace, and the arrival reports the airport in sight, I may clear the arrival for the approach (Visual Approach) as far as 30 miles or more out from the airport. Note, that this will only occur if it traffic is really slow.

If I feel confident that all the above can be accomplished, I may also switch the arrival over to the tower, normally I won't switch the arrival over to the tower until they are within 10 miles.

When I'm sequencing multiple arrivals, I do not switch the aircraft over to the tower until proper spacing / sequencing is established. Since we don't have authorization to use 2.5 miles on final, I'm restricted to 3 miles between, unless a large or heavy is involved (which adds more spacing for wake turb). VFR's I only need green between plus any required wake turb.

At KFWA we have the enjoyment of sequencing from C152's that struggle to do 60 kts on final to F16's that struggle to do only 210 kts on final. Yep, if you want to have fun, run a sequence of mixed airspeeds, or add in crossing runways for more entertainment.

Mike
NATCA FWA

GW-H,

If I don't feel confident that I can safely issue you a landing clearance or issue one to multiple aircraft, I don't. In our case approach sequences all arrivals (VFR and IFR), so as long as approach hasn't screwed the pooch, or I stuck someone in postion and hold when I shouldn't have, your early landing clearance is safe.

Safety is a two way street, and I'd rather have a pilot verify a clearance when they are in doubt than to assume and cause us both some grief.

Mike
NATCA FWA

FWA NATCA

Ausatco,

Nice web site, I'm envious that you guys have modern equipment (radar scopes & comm panels), it looks similar to the STARS scopes that they are replacing our 1960's antiques with.

Mike

Ausatco

Yeah, it's a pretty nice facility. Those tower pics are quite out of date - there's been an upgrade to both the terminal and surface movement radar displays, and Clearance Delivery is now in the Tower, replacing the data guy whose job was computerised.

(Don't blame the webmaster for the out of date info, it's not his fault!!)

The terminal radar is now part of the national computerised ATC system (TAAATS), and both it and the SMR are large high res LCD screens - much better than what's shown on the website.

All intercom, hotlines, lighting and radios are controlled through a touch screen system we call VSCMS, with each controller's screen being configured to suit his role. There are 6 positions and we have a standard configuration, but any position can be configured to do any role or combination of roles. This provides multiple redundancy to cover both equipment outages at console positions and staffing changes as traffic winds up and down during the day.

Just in case the computer system goes down, we have a copper wire bypass for each freq that goes direct to the transceivers, bypassing the computer trickery - found the need for that through hard experience.

Backup to the hotlines to the radar unit (which is remote) is copper wire telephone (not permanent lines, you have to dial an extension. That's ok, it's a contingency plan and traffic would be reduced until normal facilities return.) Other telephones go through the VSCMS computers.

The computers at each position are duplicated, A & B, with each being part of an A & B duplicated network. The two networks talk to each other, the active one constantly updating the standby one so that if the active should fail, the standby has the current configuration in RAM and will seamlessly take over.

It's pretty neat. Now, if we could just get our airspace designers to match their output to the quality of the hardware we use to administer it .... (See threads on NAS in Dunnunda)

Cheers

AA

vector4fun

AA,

Here is the actual rule from the U.S. ATC Handbook:

I work at KAUS, we have two parallel runways, both of which are used for both departures and arrivals in a normal flow. We are an "up/down" facility, that is all controllers are rated in both the Tower and Approach Control, and rotate through all positions. SOP at my facility is that arrivals be turned over to the Tower between 15 and 5 miles from the airport, and, as Mike said, Approach is responsible for the approach sequence, Tower sets the landing sequence, blending any local pattern traffic into the flow of arriving traffic.

You should notice that the U.S. rule requires that we inform the pilot what and where the preceding aircraft is. We must also inform the arrival closest to the runway of any traffic we have holding in position on a runway for departure. Likewise, we must tell any departure holding in position about the closest arrival for that runway. The professional pilots I work with (and who are used to the U.S. system) seldom express any difficulty maintaining situational awareness of their position in the landing sequence or with departing traffic ahead. Of course, some of the newer pilots are a bit overwhelmed by all the chatter. It would be quite common here to have two or perhaps three aircraft cleared to land on each runway during busy traffic in VMC weather.

During IMC wx, we are required to maintain a stagger between arrivals on the parallel ILS approaches, so it would be uncommon for Tower to be talking to more than three or four (total) aircraft on approach for both runways. When the visibility deteriorates to the point we cannot physically see aircraft on the runways, or exiting the runways, then naturally, most controllers will get a bit more cautious. I certainly do. As yet, we do not have an ASDE system, but are (were) scheduled to receive one in a couple years. (Never believe good news until it's seen walking in the front door.)

The majority of the time, in VMC wx, the arrivals will already have the preceding aircraft in sight when contacting the Tower, OR, the spacing is great enough that separation is not a factor, providing the first aircraft is still mechanicaly capable of taxiing under it's own power after landing... Since in the U.S., Pilots are equally responsible for maintaining safe and proper spacing with another aircraft ahead, IF he has it in sight, , then the procedure is really seldom a problem. Obviously, the controllers bear most all the responsibility in IMC wx, but with proper spacing and appropriate groundspeeds and closure rates, again, we seldom have a problem with the procedure. If all else fails, send somebody around!

Don

ps The entire U.S. ATC handbook is available here:

http://www1.faa.gov/ATpubs/ATC/index.htm

edited in vain attempt to improve my grammar....

Ausatco

Thankyou, Vector, that is exactly the info I was after, especially the application of it with parallel runways in operation.

And thanks for the link, too.

AA

Moorsel

Your question can be splitted in two:
a. what is the landing minima separation
b. when a clearance to land should be communicated

In Europe there are mainly 2 common references (ICAO Doc 4444 and ECAC APATSI Manual), but a wide range of different practices and national ATS manuals throughout Europe.

---Question A---
What is the landing minima separation

Landing separation minima ( Doc 4444 par. 7.9.1) :
[...] A landing a/c will not normally be permitted to cross the runway thresold on its final approach until the preceding departing a/c has crossed the end of the runway-in-use, or has started a turn, or until all preceding landing aircraft are clear of the runway in use.

This minima can be reduced
(Doc 4444 Par. 7.9.2)
Provided that an appropriate safety assessment (safety case) has shown that an acceptable level of safety will be met. [...]

My QUESTIONS would be: which landing minima do you apply? In case your minima is different from par. 7.9.2, have you conducted a safety case which shows that an acceptable safety level can be met?


---Point B---
When you should clear an a/c for landing?

(Doc 4444 Par. 7.9.3)
An a/c may be cleared to land when there is a reasonable assurance that the separation [..] will exist when the a/c crosses the runway thresold, provided that a clearance to land shall not be issued until a preceding landing a/c has crossed the runway thresold. [...].


According to APATSI the prescription in Par. 7.9.3 applies in case of " Landing clearance based on anticipated separation".

What you decribe in CDG ( e.g. providing a landing clearance to the N3 in sequence together with the traffic information about the preceding traffic), it is not in conformance with ICAO provisions. In APATSI Manual, this procedure is called "Land After (Pilot Assessed)". Some States in Europe (e.g. France and U.K.) have been applying it for several years.

Ausatco

Moorsel, thank you. That clarifies the European situation for me.

Cheers

AA

M609

FWA NATCA: Cool to se that someone is still using those old scopes. Ours have not been used in a while, and they recently hauled them away.


Our Approach facility

As for the landing clearence, we cannot give landingclearence to an aircraft unless the preceeding have vacated. (General rule)
For light single engine ac, we can give clearence when preceeding is 1000 meters down the runway (landing or departing) The figure is 1500 meters for other light aircraft.

FWA NATCA

M609,

I'm envious of your Tracon, you even have a water cooler, high backed chairs, I'm embarrased to have pictures of our equipment on our web site http://fwa.natca.net .

Unless something pulls our funding we should move into our new tower and tracon by late 2005 or 2006.

It appears that our landing clearance rules are more relaxed than what you have, the key is SAFETY, if it isn't safe we better not be doing it, and one has to remember that just because it may be legal, doesn't always mean its safe.

Mike
NATCA FWA

Canarsie Climb

Excellent thread...I was wondering about the landing clearance (US method) on another forum and was directed here.

I'm a lowly PPL and recently flew in the US for the first time (in Houston). I was quite surprised to receive a landing clearance whilst downwind with 2 ahead. Admittedly it was very VMC but quite different to the UK method where we quite often receive a landing clearance whilst sailing over the perimeter fence.

I then spent a fair amount of time sitting in my hotel room at the MGM Grand in Las Vegas clutching my handheld scanner marvelling at the 'chaotic' RT with respect to traffic at McCarran. Well it's cheaper than roaming the casinos.

I have to hand it to you Americans. It's not pretty to listen to but seems to get the job done!

radargeekgirl

Sorry for jumping in but after reading the excerpt from the US handbook it seems that there is an awful lot of talking to get the landing clearance out early.

Wouldn't it be easier to say "c/s runway 14 number 3" then when the clearance is available "c/s cleared to land" It sounds like there is an amazing amount of traffic info being passed. I guess you would get used to it after a while. I guess I also am confortable with only issuing the one landing clearance at a time. I guess the other thing that doesn't help is the fact that I usually am running a reasonably busy circuit with arrivals and departures and although approach will sequence arrivals they haven't they foggiest what I have in the circuit!

Is there anyone out there who has controlled in more than one country and can comment on/compare the different RT?

RGG

Jerricho

It's funny you mention this rgg, as having moved from the London terminal area to Canadian airspace, the traffic information passed here is exponentially much higher and is something I have had to get used to.

ManOps (Canadian version of MATS) states thou shall pass traffic information to aircraft that are going to be separated by the minimum standard, even if they are in the cruise. Not required in Blighty.

radargeekgirl

Jerricho,

Just confirm that if you only require a 500ft standard, which you have in place, you still have to pass traffic, even though the aircraft are separated and are going to remain so??

If that is the case where I am I wouldn't stop talking!!!

Jerricho

RGG that's correct on both counts.