Distance Between Aircraft on Taxiway

[Maverick]

What is the distance as per Law / Operations / Safety required to be maintained between 2 or more aircraft taxying ( Jet & Jet / Jet & Turbo-Prop / Turbo-Prop & Turbo-Prop ) on a taxiway..
Many Thanks. :)

[Spitoon]

If you mean following one another.........pilot's responsibility, but if they don't touch then it's generally OK.

More serious answer - there is nothing specified and it's a question that is being asked as we in ATC move toward more sophisticated surface surveillance systems (Adavanced Surface Movement Guidance and Control Systems or A-SMGCS to give it the generic name). Some want to use such systems to replace visual observation from the tower and to use it like it was daylight during LVOs. But trying to apply the separation and control concepts that we are used to in the air is not working very well! Lots of work going on at present but no clear answers yet as far as I know.

[TheOddOne]

I know that this isn't exactly what was asked, but it is an answer of sorts. ICAO Annex 14, as interpreted by CAP 168 in the UK lays down minimum taxiway widths for use by various classes of aircraft. For instance, a Code 'E' taxiway must be 47.5 metres either side of the centreline and is for use by 747-400, for example. Code 'F' is the latest specification for NGLAs such as the A380. Thus, if you want to have 2 parallel taxiways for unrestricted use by 747-400, the centrelines must be 95 metres apart. There are also minimum specifications for radii of turns and width of paved surface as opposed to grass or fresh air.

The waters become a little muddied when referring to taxiLANES. A Code 'E' taxilane can be as little as 42.5 metres but there are restrictions on where you can have these, such as cul-de-sacs. You can't just take any old narrow bit of Code 'D' taxiway and upgrade it to 747 by calling it a taxilane (well, you CAN, but try toughing it out with SRG!!!) Things get even murkier at holding points. Look at the various AAIB reports into wingtip dings at Heathrow for the problems of designing these huge expanses of concrete.

Don't confuse taxiway codes with runway categories. There's a handy table in CAP 168 that explains the lot. Chapter 3 is the place to go for - too much to cut & paste here.

Cheers,
The Odd One

[Piltdown Man]

Fortunately, that one is still common sense. I also don't particularly fancy any legislation here either - we've got enough as it is!

[Musket90]

Not sure if there is anything specific for taxiing aircraft following another, but at runway holding points where similar types are queuing pilots tend to use a gap similar in length size to the types they are flying. In the case of B737 size behind a heavy then gap seems to be increased to the size of the heavy. Presumably this to minimise risk of jet blast by preceding aircraft when breakway power is used causing FOD issues to the following aircraft.

The taxiway/taxilane separation is complex and depends which maximum size aircraft the taxiways/lanes are used for and what is considered to be a taxilane. Also CAA separations sometimes differ from ICAO. The reason for the reduced distances in taxilanes is that aircraft are taxiing at slower speeds therefore reducing the risk of collision with other obstructions.

[Capt Claret]

The Australian CAOs at CAO 20.9, section 5.1.4 stipulates the following:

For a Turboprop @ or < slow taxi power, the min distance behind is 15m,
For a Turboprop @ breakaway thrust, the min distance behind is 23m,
For a Turbojet @ or < slow taxi power, the min distance behind is 30m,
For a Turboprop @ breakaway thrust, the min distance behind is 46m.


There is no mandated distance once both are on the move, that I am aware of. The trouble with being at the slow taxi distance, is that if the aircraft in front stops, so too will the one behind, and presumably the one in front will need to use breakaway thrust, which requires 50% mors separation as that when slow taxiing. :eek:

[discountinvestigator]

I deal with collisions on taxiways a lot. They usually cost 4-5 million USD.

Unfortunately, air law can be a pig at times, and usually regarded as pilot fault. There is no requirement on airport operators to tell ATC what aircraft can pass and where! I even remember pointing out one rather narrow passing place to the airport operator/ATC service provider (same entity). Notes were written.

Three months later, they sent the photographs to prove I was right. You could not pass 2x767s there.

[Maverick]

Thank you mates for your answers.
I came up with this Info in the Jepp Part C but it applies only to certain airports like China where u keep 50m distance between 2 aircrafts on a taxiway.

Cheers once again for your posts / links .

Happy Taxying.

Mav..;)

[Smudger]

How 'bout common sense? If the aeroplane in front could possibly blow you over, would it be a good idea to stay a sensible distance away? For heaven's sake...

[Maverick]

Sure Smudger Common sense is to be applied in All cases,

But as always Aviation has always been more than just applying common sense. Its just if there was any legislation mentioning the same is what I was interested in finding out.
Just as one wudnt take off if the Visibility was poor anyways, but everyone's definition of poor visibility is just not the same. And that is why we have figures for LVP's.