What's My Aircraft Type?

[Gonzo]

DFC,

As a pilot I am very aware of the UK differences - and would not hesitate to file an MOR if I had a wake encounter that was possibly as a result of these local adjustments to the ICAO categories which operate not just on a national basis but in some cases are only applied at specific airports.

Are there differences between airports now?

Thankfully there is a European Directive landing on the desk of ATS standards that requires the UK ATS Authority to align it's procedures with ICAO as an interm measure prior to the introduction of European ATS Requirements. Let's hope a few of these "local differences" can be weeded out.

Ironically, the RECAT project to reclassify wake vortex categories has proposed a six category system that looks very, very similar to that which we in the UK already use!

[ATCast]

I think it would not be not too difficult to implement a check in the flight data processing system that verifies the actual aircraft type based on the ICAO 24 bit address in the Mode S replies / ADS-B squiters. The data is there already, all that is needed is a database that links the 24 bit address to the aircraft type and there you go. Maintaining that database up to date is of course critical for such a system to work.

ATCast

[HEATHROW DIRECTOR]

ATCast.. Have you seen how inaccurate some of the info from ADS-B is? Hex codes are not 100% accurate by any means.

Is it really a major problem for a pilot just to say "737"? I think not!

[055166k]

V1

Experience in the UK has shown that it is beneficial to vary from the ICAO wake turbulence separation standards.....the UK uses 4 rather than 3 categories generally. Consider the need to maximise runway utilisation at a busy airport such as Heathrow which is bursting at the seams capacity-wise...and which is almost unique in the UK for dual runway operation. Whereas Approach at a single runway operation might use "gaps" to get departures away, Heathrow has a dedicated arrival runway. In order to maximise landing efficiency there is a unique sub-categorisation for wake separations.....for example "upper medium".....this allows a phenominal increase in landing rate whilst still providing adequate safety. I don't do Heathrow Approach except in abnormal circumstances.....hopefully one of our Heathrow colleagues can correct any errors that I've made....and elaborate further on the categories. You can appreciate how vital it is to know exactly which type and/or model of aircraft you are flying. VISIT US AND SEE!!!!

[ATCast]

@ HEATROW DIRECTOR

Is it really a major problem for a pilot just to say "737"? I think not!

I wouldn't think so at first, but after reading your previous post:

you would not believe it but pilots are not beyond giving the wrong type on the R/T. Incredible, but true.

I started thinking about possible solutions to this waste of comms bandwidth and potential safety hazard.

Have you seen how inaccurate some of the info from ADS-B is? Hex codes are not 100% accurate by any means.

I am aware that hex codes are not 100% accurate, nor is anything else in surveillance. In civil aircraft the accuracy is I guess above 99%, military is lower. If you start using the hex codes for this purpose, the percentage will rise when you give feedback to the operators.

Sightly off topic:

Not sure to which inaccuracies in ADS-B you are referring to. There are quite a few aircraft that send inaccurate position, but they indicate that they do so and therefore can be identified as non-suitable ADS-B targets.
Few installations send misleading data. But there is improvement and I am sure that the wrinkles will be ironed out after the EC decides on the mandate for ADS-B in Europe.

Best,

ATCast

[tc_atco]

This is an example of playing off the risk of assuming the filed type is correct versus the potential for frequency congestion and some mild controller/pilot RT irritation.

The much greater risk is that the filed type is incorrect, and the safety implications this would result in. There's lots of ways we could cut down on RT time but the efficiency gain on the RT would be negligible compared to the safety benefit we'd surrender.

In an ideal world all filed plans would be correct, but some aren't and therefore currently the most robust and also the cheapest way is to get you to report it on the RT. If the RT congestion is so bad the controller should split the sector to relieve the pressure.

Type changes are passed onto the tower so they can ensure their conditional clearances are accurate, and I think some stands can't take certain types? Maybe someone who can see planes at their place of work can answer that one.

[HEATHROW DIRECTOR]

ATCast. With the availability of various magic boxes permitting Joe Public to watch "radar" on his PC, several enthusiasts web sites have sprung up dealing with matching hex codes against aircraft registrations, etc. Considering the extremely high integrity of SSR I think you might be surprised at the poor integrity of Mode S information as far as hex codes go and positional inaccuracies with ADS-B are a daily occurrence. Take a look at this picture of an SBS display yesterday.

MSR777.jpg :: Other subjects :: Fotopic.Net

At the time the picture was recorded, MSR777 was actually established on the ILS about 7nm behind the one ahead. This is not a one-off, but one of anything up to a dozen in one day I have seen. Airline and type are irrelevant but whether particular aircraft always display this problem I do not know.. Safe to say that from the ATC aspect, I imagine that this would be unacceptable.

I'm very interested in this subject and would be glad to hear more..

[eglnyt]

I'm very interested in this subject and would be glad to hear more..

The thread is drifting a bit but search the Eurocontrol site for Cascade and look up Validation and you'll find loads on the subject. Positional inaccuracies with ADS-B are a daily occurrence but the Eurocontrol data shows that these aircraft are also indicating that the position report is of poor quality. Does the SBS box display the quality indicator ? Unless the aircraft is flying in mandatory ADS-B airspace it is not obliged to transmit accurate reports or be equipped to do so.

[Bagheera]

Type changes are passed onto the tower so they can ensure their conditional clearances are accurate, and I think some stands can't take certain types? Maybe someone who can see planes at their place of work can answer that one.

A good point there tc atco. The stand allocation system at my airport works off flight plan data. There are a number of stands that will fit a B735 but not a B738 or a B762 has turned out to be a B763 and a hasty call to airfield ops has had to be made before the back of stand road gets blocked by a stuck out rear!

[HEATHROW DIRECTOR]

Unless things have changed, at most major UK airports ATC has nothing to do with stand allocation which is a matter for the airport authority and the airlines. I believe that the prime purpose of requiring pilots to state aircraft type is wake turbulence separation..

[Mad As A Mad Thing]

It's not just wake turbulence and stand allocation problems. Both of which are very real safety matters, but also if the type hasn't been changed on the flight plan then the whole flight profile has possibly been filed with the wrong levels & speeds too. This could mean that the flight details don't even arrive at the sector you are expecting to fly through as you are flight planned into a different (lower or higher) sector.