Parallel entries to the racetrack

[bookworm]

According to my reading of PANS-OPS (3.3.2.2), I can join a racetrack procedure as a sector 1 parallel entry.

But...
3.3.3.4 ... If a further descent is
specified after the inbound turn, this descent shall not be
started until established on the inbound track ("established"
is considered as being within half full scale deflection for
the ILS and VOR or within 5 deg of the required bearing for
the NDB)

The timing specified on some French procedures seems to make it mighty difficult to do that from a parallel entry when there's a FAF or FAP outside the facility.

For example:
Agen L/DME 29 (http://www.sia.aviation-civile.gouv.fr/aip/enligne/METROPOLE/AIP/IAC/IAC%20AD%202.LFBA.pdf)
At 120 kt I cross the AG NDB (3.5d from the AG DME) at 2500 ft and proceed outbound on 114 for 1 min 30 s. I then, at about 6.5d, make a right turn to intercept the I'll end up 294 inbound to AG. I'm expecting to be turning through 294 (180 degrees into the turn), still the diameter of a rate 1 turn off the inbound track, at about 6.5d. But the FAF, at which I should leave 2500 ft is at 6.5d!

Another:
Albi L 09 (http://www.sia.aviation-civile.gouv.fr/aip/enligne/METROPOLE/AIP/IAC/IAC%20AD%202.LFCI.pdf)
At 120 kt I cross the AB at 2200 and proceed outbound on 271 for 1 min 30 s. I then make a left turn back to intercept the 091 to the AB. With a 30 degree intercept, I'll get established about a mile outside the AB, which I'm then expected to cross at 1250 ft. (I do have 1.6 miles after the AB if necessary before the MAPT to get down to the MDA which is 1250 anyway.)

Amiens L 30 (http://www.sia.aviation-civile.gouv.fr/aip/enligne/METROPOLE/AIP/IAC/IAC%20AD%202.LFAY.pdf) looks similarly difficult.

Calais ILS 24 (http://www.sia.aviation-civile.gouv.fr/aip/enligne/METROPOLE/AIP/IAC/IAC%20AD%202.LFAC.pdf) was the one that first got my attention. It would seem that it would be very difficult to establish inbound before the glideslope intercept point at 6.1d.

Am I misinterpreting PANS-OPS's permissiveness with regard to parallel racetrack entries, misinterpeting its strictness in forbidding descent before established inbound, or are some IAPs almost impossible to fly? :confused:

[BEagle]

The Sector 1 (parallel) join is designed - as far as I'm aware - for entry into the holding pattern.

I always thought that, having overflown the VOR (beacon joining) and tracked outbound for the specified time, the inbound turn off the entry is flown to roll out direct to the beacon, not to 'couch the needle' in an attempt to achieve the holding radial. Then, overhead the beacon, the hold is entered (beacon holding) and the approach flown from the subsequent inbound turn.

Which is why I would always try to fly a Sector 2 or 3 join!

[Empty Cruise]

Agen Lctr+DME 29 : the racetrack is protected out til D 9,5 for the outbound leg. Since you are permitted to have same speed (110/140 KIAS) until the IF (in this case established inbound), you are also protected similarily to D 9,5 on brg 114 deg. from the AG. Solution - go to 9,5 D, then turn inbound ;)

Albi - states clearly that the timing outbound is 2:30 for Cat A or 2:00 for Cat B or C. So go to the appropriate timing - should again solve the problem.

Amiens - agree, no DME present, so might need one turn to get established. The procedure is at the MSA, so you could extend outbound, but then the question arises - when to descend?

Calais - again, stated time for IAS lower than 130 KIAS = 2:00. Should solve the problem.

Remember - if you are protected on the outbound leg of the racetrack, you are also protected on the outbound leg of the parallel entry. It doesn't matter how you get there - it's just a block of airspace free from obstacles.

Hope this helps & saves some fuel. Brgds from
Empty.

Edited for spelling - danmed lydsexia...

[Leo45]

Empty Cruise is absolutely right. There's a total misconception, in many UK FTOs, about sector 1 entry in a race track procedure. What they teach is nothing but a sector 1 entry in the hold followed by the outbound leg of the race track procedure from the beacon overhead (as described by Beagle).

As far as PAN-OPS is concerned, you can perform a sector 1 entry in the racetrack, then, having intercepted the FAT, you can descend with the procedure as you are already on the final approach track.

It took me a while to convince a CAAFU examiner but I never convinced the then Head of Standards at the FTO I was working for... :hmm:


Edited cause my brain was on strike earlier...

[bookworm]

I agree entirely Leo45. Just to be absolutely clear, my question concerns a sector 1 (parallel) entry, not a sector 2 (offset).

[Leo45]

God, my brain has turned into a mushroom. I was indeed talking about Sector 1 entries, in other words parallel. My apologies...I shall edit my previous post at once.

[JeePilot]

I always thought that, having overflown the VOR (beacon joining) and tracked outbound for the specified time, the inbound turn off the entry is flown to roll out direct to the beacon, not to 'couch the needle' in an attempt to achieve the holding radial. Then, overhead the beacon, the hold is entered (beacon holding) and the approach flown from the subsequent inbound turn.

I was taught both ways are suitable for parallel entries into holds, especially over an NDB. Of course one must get a feeling for the winds on the outbound leg to ensure this method will be feasable.

As a side note are "sectors" 1,2, and 3 in refrence to the different entry procedures for holds? Parallel, offset, and direct respectively? Are there also "sectors" for approach joining pro's?

[Empty Cruise]

Jeepilot,

Tracking outbound on a parallel entry should give you a pretty good idea about the wind.

The idea about tracking direct to the beacon might be a good idea to prevent the student from trying to get established & then drop like a stone to try to establish on the approach profile.

Answer - fly the CANPA profile. Easier, even single pilot in a Cessna or Beech. Safer - and less complex, especially talking ME pistons executing OEI approach, since there will be no level segment on the approach (unless circling).

Any UK FTOs teach CANPA techniques? :)

Brgds,
Empty

[OzExpat]

For some reason unknown to me, I was unable to open the link for the Agen procedure, but I've looked at both Albi and Calais. I have to assume that, as holding does not appear to be separately defined, the racetrack is protected for Sector 1, 2 and 3 entries.

I can't read French so don't know how Empty Cruise came up with 2 minutes outbound timing but am prepared to accept that he's correct. That being the case, a descent from 2200 FT to 1250 FT requires a ROD of 450 FPM in nil wind, so the approach is quite flyable.

Much the same for the Calais approach, as a 2 minutes outbound timing should allow descent from 2000 FT to 1310 FT at a ROD of 345 FPM in nil wind. Should be plenty of flexibility to go steeper than that, if you end up closer to the navaid at the end of the reversal from the Sector 1 entry. All in all, this procedure seems to be readily flyable at the outbound timing of 2 minutes.

If you're going to use just 1 minute on the Sector 1 entry, you'd undoubtedly need to fly around the pattern before starting the final descent, or your ROD would likely be excessive.

[bookworm]

I can't read French so don't know how Empty Cruise came up with 2 minutes outbound timing but am prepared to accept that he's correct. That being the case, a descent from 2200 FT to 1250 FT requires a ROD of 450 FPM in nil wind, so the approach is quite flyable.

On the Albi L09 it's "Hippodrome : T = 1 min 30", which means a 1 min 30 racetrack outbound. But I don't think the difference between that and 2 min is significant to the issue.

I didn't explain the reason for my confusion very well, OzExpat. The charts appear to depict the turn at 2200, with descent to 1250 after establishing inbound. On a sector 2 or 3 entry I should roll out from the turn close to the inbound track. Fine, in nil wind, I've got about 1 min 30" to descend 950 ft. Not a problem.

However for a sector 1 entry, I will roll out of the turn the diameter of a rate 1 turn south of the inbound track. If my interpretation of PANS-OPS is correct, I now have 1 min 30 to first establish on the inbound track of 091, then descend the 950 ft.

Can I descend to 1250 before/during the turn, or after the turn but before establishing on the 091 inbound track?

It says that entries into the racetrack are protected, but does that guarantee protection on the southern straight leg at 1250 ft?

[Hudson]

My understanding is that when you turn at the end of the timing period following a parallel entry, the idea is to intercept the inbound track to the fix - not track directly to the fix.

This gives you time to establish yourself on the inbound track of the holding pattern before reaching the fix and thus avoids the awkward manoeuvering needed to regain track after the fix - where depending on the final angle that you attacked the fix as you approached it after the parallel entry, you could find yourself badly placed on leaving the fix on final.

For example if you tracked direct to the fix rather than intercept track to the fix, you could finish up 25-35 degrees off track after passing the fix and having to S turn back to get on track again.

[BEagle]

Yes, you might indeed finish up 30 deg off track - that's part of the design. So you then go round the hold again...to refine the holding track the next time inbound.

Trying to make good the inbound track after turning back to the beacon during the Sector 1 (Parallel) entry is going to be quite difficult in anything except low speed a/c which can achieve higher rates of turn than those which cannot achieve Rate 1 at 25 deg AoB. Hence wherever possible, it's best to ensure that you can navigate to achieve a Sector 2 join if approaching from non-holding direction! Usually achievable as the holding radial is normally aligned with the arrival route...and there's a 5 deg flexibility to benefit from!

[DFC]

Making a parallel entry the aircraft parallels the inbound track it does not backtrack along it. This gives the aircraft some advantage with regard to radius of turn when turing inbound.

In a racetrack when making a parallel entry it is mandatory to regain the inbound track prior to reaching the beacon.

For Calais, if the speed is below 130Kt, the aircraft can only enter the racetrack after first entering the hold.

Since you are at 120Kt, you have no choice but to make an entry to the hold and then fly the racetrack.

Regards,

DFC

[Empty Cruise]

Sorry, OzExpat & others, :oh:

Looked at the wrong procedure for Albi 09, Lctr 09 indeed states a timing of 1:30 for the racetrack. However, since the navaid, tracks & altitudes are the same as for the VOR or Lctr LLZ approach to 09, the airspace protection from obstacles will be the same. Therefore, one could inform the controller that one would like to extend to 2:00 or 2:30 depending on category, and - provided that is approved - enjoy the same obstacle clearance while leaving more room to establish. But yes, 1:30 should be enough, especially if you keep 120 kt. outbound (Cat. B limit of 2:00 applies).

Bookworm, yes, indeed without DME or any other supplemental naviagtion, you face the same problem as in Amiens. 1 round in the racetrack probably required. And absolutely right, you cannot dsc before being established on the inbound track, so no dsc below procedure altitude during the turn. ;)

DFC, sorry, but cannot see why an aircraft flying less than 130 KIAS cannot make a paralllel entry to the racetrack, time outbound to 2:00 as described on the plate, and then make the inbound turn from there? Or even go al the way to DIPKA at MK DME 9,6, then turn inbound? Especially since the initial & intermediate approach altitudes are at the MSA, AFAIK we could proceed on MK brg 063 deg. until 23,5 NM and then turn inbound (allowing 1,5 NM turn radius). You are spot on on the requirement to track the inbound course in a racetrack after a parallel entry - I must admit I do it with both holdings & racetracks, so I only have to use one procedure :suspect: - lazy as I am :)

Regarding the suitability of higher-speed aircraft to fit into the procedure - agree, a real PITA. Assuming that anything being CAT B or above will nowadays have B-RNAV, arriving from the WNW I would personally - in lieu of vectors - ask to self-establish via DIPKA. Avoids the speed/config hazzle - again being a lazy pilot beliving in making it the easiest way - when that also turns out to be the safest way.

Best reagrds to all from
Empty.

Once again - lydsexia slrikes beck :doh:

[DFC]

Empty Cruise,

sorry, but cannot see why an aircraft flying less than 130 KIAS cannot make a paralllel entry to the racetrack

Because it says "IAS below 130Kt: Entry into racetrack only via holding" on the chart!

As for tracking out to DIPKA, that is not a parallel entry. Parallel entries do not track back along the inbound course.

At Agen, all the arrival routes are from directions that do not require a paralllel entry. The aircraft would have to be arriving from within the large Military area SW of the aerodrome to require a parallel entry.

At Albi, the AFRIC arrival does require a parallel entry. However, for the Locator approach, I would initially join the hold so that the inbound timing could be accurately determined on the racetrack entered via the hold. Note also the minimum altitude when arriving from AFRIC - one needs to loose a bit more height.

No point in rushing an approach especially when weather is on the limits!!

More important is that while you can correctly say that the racetrack altitude is the same as the MSA and you will be terrain safe ot to 25nm, the procedure must still be followed because ATC may be using certain separations from other arriving or departing flights that require you to be on the procedure........At Calais you don't have to go too far to enter the adjacent FIR!!

Regards,

DFC

[Pilot-H]

As a picture is worth 1000 words, here's 2000's worth:


Racetrack procedures illustrated 1 (http://www.cirrus.flyer.co.uk/hitchhiker/racetrack2.jpg)

Racetrack procedures illustrated 2 (http://www.cirrus.flyer.co.uk/hitchhiker/racetrack1.jpg)

[Empty Cruise]

Hi DFC,

Sorry, have looked at the LFAC ILS 24 again, and not able to find the note on "IAS below 130Kt: Entry into racetrack only via holding", but then again, my french is not the best :(

And had absolutely no intention of advocating procedures not approved by ATC. Indeed, the first paragraph in my last post should indicate that I only advocate the exact opposite.

I agree with you on rushing approaches - it has no place in commercial air traffic. All the more reason to design procedures that do not tempt pilots to rush the approach. A simple STAR over 3 or 4 waypoints should be able to get the aircraft to DIPKA on a more or less square downwind/base arrangement.

As for tracking the 063 QDR - well, without an FMC or other duplicate NAV, I would strongly recommend that pilots use track guidance where available. Looking at the design of racetrack primary obstacle clarance areas, it is clear where the margin is, and it is not on the side of the racetrack facing away from the turn. So even though Doc 8168 clearly shows that you should indeed parallel, not track, I would suggest that prudence dictates using the track guidance available, especially since WCA might be an unknown factor. A 1:30 timing will not get you into serious trouble, but a 3:00 timing when doing speeds at the upper end of the allowable range? Again, asset managemant & risk reduction strategies would indicate that using the available track guidance (i.e. tracking QDR 063) is the safer option. It does not give you the same turn advantage, but then again - never rush the approach, so if 1 more turn is required, so be it!

Regarding weather you - with ATC permission - could extend to DIPKA - well, it's not a parallel entry the way Doc 8168 describes it - but from a practical point of wiev, it will offer you the exact same benefits as a parallel entry, only with room to shoot the approach the first time, saving you some hundred kg. of fuel :ok:

Best regards from
Empty

[DFC]

Empty,

I am using the Jeppesen Chart (11-1) dated 7 Nov 03. It has the statement in the plan view.

As for tracking the 063 QDR - well, without an FMC or other duplicate NAV, I would strongly recommend that pilots use track guidance where available........A 1:30 timing will not get you into serious trouble, but a 3:00 timing when doing speeds at the upper end of the allowable range? Again, asset managemant & risk reduction strategies would indicate that using the available track guidance (i.e. tracking QDR 063) is the safer option.......

It is possible to judge that the aircraft is not diverging from the requirement to parallel the inbound without an FMS...simply use the NDB and DME to orientate oneself. Remember also that drift increases as speed reduces. Thus the faster the airspeed used in the procedure, the less the aircraft will drift due to uncorrected or a not fully corrected crosswind component. (At 120 Kt one has 1 degree of drift for every 2Kt of crosswind......at 180Kt is is 1 degree for every 3Kt!.......quite a change if there is a 20 or 30Kt crosswind!)

DIPKA is a fix used in the arrival from KOK. That is all. It has no relevance in the racetrack procedure. In fact at the maximum speed of 160Kt, an aircraft would be abeam DIPKA in the inbound turn.

Overall I can't see a problem with the procedure. Perhaps with a strong easterly wind one could make hard work but a 60deg intercept should be no problem and since such an approach would end in a ciccle to land, the reduced height loss required makes it easier.

Regards,

DFC

[bookworm]

"IAS below 130Kt: Entry into racetrack only via holding"

I am using the Jeppesen Chart (11-1) dated 7 Nov 03. It has the statement in the plan view.

It's an interesting interpretation: the French says:

"* Les entrées dans l'hippodrome de 1 min 30 sont protégées"

i.e. Racetrack entries of 1 min 30 s are protected.

I'm not sure how you're supposed to come to grief after 2 minutes at 120 KIAS but not after 1 min 30 s at 160 KIAS.

But anyway, let's assume you're flying a sector 1 entry at 150 kt for 1 min 30. That's 3.75 nm. Thus turning through 243 on the left turn inbound you might be 1.6 miles north of track and if you take a 45 degree intercept you'll intercept the localiser about 0.3 miles after the glideslope intercept point, allowing no time to make the 45 degree right turn back on to the inbound track. So it's almost impossible to fly. Less than 150 kt makes it worse, of course.

Albi L 09, also using a sector 1 join with a 45 degree intercept, allows you to intercept the inbound just 40 seconds before crossing the beacon inbound, where the charted altitude is 950 ft below the turn altitude. Put another way, from intercept you have 1 min 20 s to the threshold 1636 ft below. It's about 500 ft/nm gradient.

It just surprises me that the procedures are designed that way, if I'm correctly interpreting the prohibition on descent until established.

[Hudson]

Pilot-H. Thanks for the illustration "Racetrack Illustrated 1" This confirms that one should intercept the inbound track on completion of the first part of the parallel entry and not merely head toward the aid on any heading. This is what my company teaches in the 737 simulator and is looked for in an instrument rating test. No problem at all at 220 knots.

[OzExpat]

On the Albi L09 it's "Hippodrome : T = 1 min 30", which means a 1 min 30 racetrack outbound.
Thanks for the clarification bookworm. I can now tell you what the procedure requires, from a design perspective.

The holding pattern is a standard 1 minute pattern and this is where you have the protection for the sector entries. All that achieves is to allow you to get onto the inbound holding track at least by the time you reach the NDB or Locator or whatever it is. You are then obliged to fly the racetrack before achieving final approach alignment as this is the only way that you'll have enough time for descent.

This will be the basis on which the procedure was designed. Do not make the mistake of thinking that your sector 1, 2 or 3 entry is protected by the longer time provided by the racetrack. It needs to be remembered that a racetrack is not a holding pattern, it is merely a method by which to achieve reversal. It is often quite a useful too for a procedure designer whenever there is a need to limit the amount of airspace that the procedure will occupy.

One reason for such a limitation might be a closely adjacent FIR boundary, but it could be for any number of other reasons too, of course. A great deal of airspace must be protected to cater for all the available sector entries, but this will only be protected within the confines the standard one-minute pattern, unless you are above MSA and have approval from ATC.

I hope this explains the situation but I'll keep checking back to this thread in case further clarification is required.

[bookworm]

OzExpat

Thanks for that. Can I just ask for clarification of what you're saying? And I'm asking about PANS-OPS procedures here, I won't ask you to speak for the French! ;)

I'm having trouble squaring what you say with PANS-OPS Vol 1 3.3.2.2

Normally a racetrack procedure is used when aircraft arrive overhead the fix from various directions. In these cases, aircraft are expected to enter the procedure in a manner comparable to that prescribed for holding procedure entry with the following considerations:

a) Offset entry from sector 2 shall limit the time on the 30" offset track to 1 min 30 s, after which the pilot is expected to turn to a heading parallel to the outbound track for the remainder of the outbound time. If the outbound time is only 1 min, the time on the 30" offset track shall be 1 min also.

b) Parallel entry shall not return to the facility without first intercepting the inbound track when proceeding to the final segment of the approach.

c) All manoeuvring shall be done as far as possible on the manoeuvring side of the inbound track.

Are you saying that racetrack entries (as opposed to holding pattern entries), are not, by default, protected?

[DFC]

Bookworm,

Get your hands on a copy of RANT or even flight sim and try the Calais procedures. They can be done!

As far as I am aware, you are correct to say that one can make a parallel entry to the racetrack. Here is your para. b);

b) Parallel entry shall not return to the facility without first intercepting the inbound track when proceeding to the final segment of the approach

For that I read that if you are making a parallel entry and going straight into the final approach i.e. next time at the beacon you will track outbound to the mapt then you must not return to the facility without intercepting the inbound track.

The reason for that is the size of the final approach area at and beyond the beacon and the effect approaching the beacon at an offset angle could have on positioning in the final approach.

If however, you intend to go round the racetrack, you can return directly back to the beacon because that would place you no worse off than a direct entry.

Regards,

DFC

[bookworm]

DFC

I agree with you (and para b, obviously) that you have to intercept the inbound track before reaching the facility. The issue is that, in order to descend according to the charted profile, you have to intercept the inbound track not just before reaching the facility but before the point at which you need to leave the altitude of the inbound turn.

In the case of Calais, you need to leave the altitude of the inbound turn (2000 ft) at 6.1d, some 2.1d before the MK, so you have to be established by then. I don't believe that can be done reliably with a sensible intercept angle, given that the outbound is just 1'30", i.e. potentially less than 3.5 miles.

Trying the scenario on a sim proves only that it's possible to manhandle an aeroplane in such a way that it sometimes works, presumably with some extreme intercept angle. I thought IAPs were designed so that they always work.

[DFC]

Bookworm,

There is no need to manhandle the aircraft or to hae exceptional intercept angles.

With regard to intercept angles think back to your IR training days - if there was a very strong wind from say 160deg at Calais, you may use a 90deg intercept in a relatively slow aircraft and not fel uncomfortable because of the relatively slow groundspeed towards the inbound track. That would apply to turning inbound in the hold, turning inbound in the racetrack or turning inbound following a parallel join into the racetrack (to be followed by final approach).

However, with experience you will have a few tricks up your sleve that help ensure a perfect result every time. Again remember the IR training days in all those holds- better to be a bit wide and a bit long (within limits) and give yourself time to make a good intercept of the inbound track for a decent period of time.

Calais only poses a problem for you because you are flying a slow aircraft and with a low ground speed, the procedure timing does not position the aircraft far enough out to make a simple intercept.

Hint 1 - once within 5deg of the inbound course on the ADF you can descend to 1310. So if you are tight to the FAP just before intercept, you can effectively descend at something up to 1000ft/min to 1310 as soon as the ADF puts you in the right place. That will enable you to level and intercept the GS from below at the LOM. The justification for this is the Lctr approach not the ILS approach!

Now looking at the race-track. Think of the worst case scenario in no wind. Aircraft TAS 60Kt. No matter which way one does it (parallel entry or full racetrack) the aircraft will only be at 6 miles when the inbound turn is commenced. This is an exagerated example of your problem.

Hint 2 - the racetrack procedure is designed for aircraft to fly at up to 160Kt. If you are flying it at 120Kt and there is no actual wind then you can say that in theory you are causing your own 40Kt (160-120) headwind. Of course, once turned inbound you will still have that theoretical headwind so if you correct for it to the full it will take you a long time to get back to the beacon! However, there is scope for sensible corrections to the timing that will put you further out but not outside the limits of the procedure.

Remember that the racetrack is based purely on timimg.

However again having said all that, I have not had any problem with the procedure using 130Kt for the parallel entry straight into final approach or using the restriction on the jepp chart of requiring a 120kt speed to do the full racetrack before final approach.

Regards,

DFC

[OzExpat]

Good question bookworm, thanks. It's been a real long time since I've looked at racetrack criteria and have never had to use one, so I got into the habit of thinking about them purely as reversal procedures. You're right, of course, in that Pans Ops requires protection for the sector entries - I looked it up today to confirm that, so it would appear that all sector entries are protected up to 1 minute and 30 seconds.

Thus, you would not be obliged to fly the full racetrack after completing the sector entry. Of course, if you elect to fly the standard 1 minute sector entry, all you've achieved is an entry to the holding pattern. In that event, you'd definitely need to go around the racetrack to provide the full time (ie distance) for descent on the inbound leg.

Of course, even if you fly the sector entry for the full time allowed by the racetrack, you're likely to lose some valuable time on the inbound leg by virtue of having to intercept the track, so it's probably a good idea to fly the full racetrack anyway. I have to look back at the Albi procedure to check (and don't have the time right now) but I have an idea that the maximum ROD has been fiddled a bit in that procedure.

I say that because the maximum ROD that can be designed in a final segment for Category A and B aircraft is only 655 feet per minute. Cat C, D and E can have up to 1,000 feet per minute. I suspect that the procedure doesn't quite cater for Category A and B aircraft on that basis.

I will try to have another look at the procedure within the next day or so and do some maths to confirm one way or the other.

[bookworm]

Now looking at the race-track. Think of the worst case scenario in no wind. Aircraft TAS 60Kt. No matter which way one does it (parallel entry or full racetrack) the aircraft will only be at 6 miles when the inbound turn is commenced. This is an exagerated example of your problem.

I think you mean 2 miles, not 6, right? (edited: Oh no I'm sorry, you mean 6 DME, not 6 from the MK -- yes, quite so.)

But I like the train of thought, because I think it brings out the issue nicely. You're suggesting that, if the descent point is outside the facility used to define the racetrack, it's always possible to choose a speed for which you cannot reach the inbound track before the descent point.

However, there's a minimum speed for initial approaches of 90 knots. Thus I would have thought that, if sector 1 entries to the racetrack are authorised, it should always be possible to fly them at 90 knots, but possibly not at less. And I would have expected a design criterion for the minimum length of the racetrack leg time, dependent on the top of descent for the final approach, to allow that.

For example, if the racetrack leg had to be at least 1 min beyond the top of descent point (which allows something like a 30 degree intercept to work), and that top of descent point were 2 miles from the facility, that would oblige a minimum leg length of (2 miles / 90 kt) + 1 min = 2 min 20 secs. For 120 kt that could be reduced to 2 min, and for 150 kt it comes down to 1 min 48 sec. If you can't protect those lengths, then sector 1 joins should be explicitly forbidden.

But perhaps no such criterion exists.

In the particular case of Calais, it's complicated by some doubt about whether sector 1/2 entries are authorised below 130 kt.

[OzExpat]

Well now that I have the time, I tried to look at that Albi L09 procedure again. Unfortunately, I had trouble downloading it and suspect that the local gateway server is the culprit. :sad: But, I've had another look at the Calais ILS24 procedure.

I have no understanding of French at all but I suspect that the speed limits relate to racetrack timing. If this is correct, then for aircraft IAS between 130 and 160 knots, outbound time is 1 min and 30 secs. And, for aircraft below 130 KIAS, outbound timing is 2 mins. I further suspect that sector entries to the racetrack are limited to a maximum timing of 1 min 30 secs, but I might be wrong about that.

I don't see anything that looks like a speed restriction on the standard 1 min holding pattern. If this is the case, you can use a higher speed than 160 KIAS to enter the hold and slow down for the racetrack.

I see that the minima box only caters for categories A to C and, while cat. C aeroplanes can handle 160 KIAS, it's a bit slow for some of the bigger cat. C types.

All in all, not the sort of procedure to start reading about just before you start to do it! :eek: This one needs quite a bit of advance planning, to get the aircraft configured early.

[DFC]

The SIA Chart has the following statement - Les entrées dans l'hippodrome de 1 min 30 sont protégées

Using an online translator this translates into - Entries in the racecourse from 1 min 30 are protected

It seems to me that Jeppesen has interpreted this to mean that entries into the racetrack when the still air timing is more than 1 min 30 are not protected...................thus is places the warning on it's chart requiring aircraft below IAS 130 to enter the racetrack only via the holding.

If you think you are going to have problems with the racetrack where you are using 2 minutes, have a look at the Locator/DME approach where there is no racetrack and aircraft enter the final approach from the hold!................However again like I suggested previously remember that the hold is protected for airspeeds up to 170Kt IAS!!

Regards,

DFC

[OzExpat]

Yes DFC, I was just looking at the Calais L/DME approach and came up with some interesting numbers. In the best possible case, without DME, you have 1 minute to descend from 2000 FT to 1310 FT, which equates to a ROD of 690 FPM. You better hope that there's no tailwind component to deal with, or you'll be blown toward the Locator in the inbound turn in the hold and then have less time to descend.

The designer can get away with requiring a high ROD in the initial approach segment but the problem is that, if you don't reach 1310 FT by MK Locator, you're above profile for the final segment and have to use a higher ROD than is particularly comfortable.

However, as you can initiate descent during the inbound turn in the hold, when within 5 degrees of the track, it probably works out pretty well. Most of the time. Much nicer if you can use the DME of course because you've got an on-going monitor on your descent profile.

I've finally been able to look at that Albi L09 approach again too. It looks like I must've had the wrong idea about the outbound timing in the racetrack. My calculations tell me that the nil-wind ROD is less than 655 FPM and, on the whole, this approach seems pretty reasonable to me.