ICAO Questions

[MarineKC130]

I've got a few questions that have been disputed by some people I'm on det with. We don't have access to any ICAO pubs, so links to any pubs or gouge sites would be great. Please don't reply with FAR answers, since I'm asking for the ICAO answer and already know the FAR answer.

1. There is an ICAO approach that has a bold, holding pattern entry with the inbound and outbound courses specified in bold. There is a radial/DME fix that is depicted on the holding pattern on the outbound leg. This fix is specified to be flown to on the missed to re-enter the holding pattern. Dispute is whether on the initial turn on the approach you have to turn so as to fly across the fix before turning inbound (which would require either a half-standard rate turn or a divergent outbound course since the fix is outside the aircraft's normal flight path using standard rate turns) or if you can fly a normal holding pattern and disregard flying over the fix except for re-entry after a missed approach.

2. What are ICAO approach categories based on? I thought that they were on the same system as FAA uses, but have been told that they're based on the aircraft's max speed at max weight, which makes no sense to me.

Actual references to pubs would be helpful, but any answer from someone familiar with ICAO ops would be helpful. Thanks in advance.

 

[MooseTrax]

I need a picture

The description is quite complicated, but I'll take a shot. My experience has been that with ICAO approaches/holding, you need to follow it exactly as it is printed. The only time I have seen deviations is to align yourself for a base turn procedure or a 45/180, or an 80/260 procedure to meet the 30 degree entry tolerence specified in our AF Manual. As far as holding goes, the teardrop is specified for you and you must intercept the inbound course, unlike FAA where you have the option to proceed direct to the fix on the first turn inbound. As far as there categories go, they are a bit different, and you can be one category for your approach and another for your departure as they have some turning departures with speed restrictions. I will look in AF Man 11-217 Vol I to see if I can find something. Good luck and fly safe out there.
Regards,

 

[MarineKC130]

Picture

Below is a link to the approach. You may have to be on a .mil server but I'm not sure. The approach I'm looking at is the "Apton ILS Rwy 36". This may help clarify what I'm talking about.
https://164.214.2.62/products/digit...MIDDLE_EAST/LEOPOLD_SEDAR_SENGHOR_INTL__GOOY/

 

[MooseTrax]

Re-attack

I have asked some smart folks about this and this seems to be the concensus. You must fly to the R-199/15 fix and enter the holding pattern. The holding pattern and therefore the offset are based on the max speed allowed in the holding pattern, in this case it is published as 230 KIAS. Our procedures say to fly ICAO holding at a bank angle of 25 degrees or 3 degrees per second, whatever is less. At 230 KIAS at 2600' MSL, 3 degrees per second is about 30-32 degrees, so you would need to use at 25 degrees. At 230 KIAS at 2600' MSL and 25 degrees of bank you would approximate a 4-mile turn diameter, which is what you have in this case (at 15 dme = 4 radials per mile and you have 17 radials difference(199-182 = 17)). If your holding speed is significantly slower, then you need to do your best to maintain the bold course, this may require you to fly less bank, but because the outbound fix is radial/dme defined, you need to do your best to fly it as depicted.

Our books also say that if a procedure is limited to specific aircraft categories, these are the applicable max speeds:

A = 110 kias
B = 140 kias
C = 240 kias
D = 250 kias
E = 250 kias

I know for the C-17 specifically we are a CAT D FAA airplane, which is based on 1.3Vso at max landing weight. We still use the CAT D minimums on ICAO procedures, and in this case wouldn't come close to the limit as our prefered holding and maneuvering speed is 230 kias. I have no idea what Herc speeds are, so you will have to be the expert on that. As an additional note, ICAO sometimes has turning departures that are designed with max speeds to remain within protected airspace. If the departure is limited to specific aircraft categories, these are the applicable max speeds:

A = 120 kias
B = 165 kias
C = 265 kias
D = 290 kias
E = 300 kias

Notice they are not the same as the approach category speeds which is rather confusing. Good luck. If your are going to Dakar, have fun, it is a neat place.
Regards,

 

[Sammy]

I could be wrong, but I think when you first hit the the IAF and fly the holding pattern in-lieu of the PT you only have to go outbound to the 15 DME fix. Notice that there is no "Remain w/in" a certain distance or a "time limit" like most of the IAP's in the US have. These limits keep you in protected airspace. The requirement, in my opinion, to intercept the R-199 is on the MAP only. There is no safety advantage in going out to the R-199 on the outbound leg of the hold if your turn radius is well inside the R-199. All that airspace is well protected. 6 to 1 half a dozen the other maybe. Trust me, nobody in Senegal is goin to give a rats behind.

 

[MarineKC130]

No kidding on the controllers. I hear people in the states whine about the occasional controller who isn't 100% perfect. If they only had one flight dealing with a third world controller...

I completely agree with what you're saying on the protected airspace. I see no advantage in shallowing my turn to make it to the 199 radial, but some people say that you have to fly the procedure exactly as printed. If that is true, I wish I could find a reference to back it up. The only thing I can see to support it not being true, is that it says in the legend of the plates where the holding patterns are depicted that non-standard limits will be depicted. You could infer that the 199 radial is a limit, and not a fly over point. This obsession may seem pathetic, but sometimes on det you kind of run out of positive things to think about.