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longobard
14th Dec 2010, 09:25
Anybody knows why YMML ILS 16 CAT II, and other asian airports, minima doesn't report RA but only DA(DH)?

Which operational consequences?

aterpster
14th Dec 2010, 19:12
longobard:
Anybody knows why YMML ILS 16 CAT II, and other asian airports, minima doesn't report RA but only DA(DH)?

It happens in the U.S., too. Usually, the terrain is sufficiently irregular prior to the runway that the RA reading is either inaccurate or unreadable.

Which operational consequences?

None, unless imposed in an operator's state authorization.


http://tinyurl.com/3y42zcj

172_driver
15th Dec 2010, 02:48
How do you establish your DH on that approach? Using the IM?
I know in EU-OPS, DH must be established using radio altimeter for CAT 2 and 3 ops.

bigduke6
15th Dec 2010, 14:45
If RA is not approved, then DA(H) is determined by inner marker, and backed up with baro altitude.

So for the Europeans if DH must be established with RA, then can they not do Cat II approaches to places like KSEA, or others, where IM is used instead, due to the underlying terrain???

Mansfield
15th Dec 2010, 15:10
The use of the inner marker in this case is the standard procedure for US operators; however, it must be approved in that carrier's Op Specs. Not all carrier's programs incorporate this. If they do not, the approach is not authorized.

AC 120-29A also references the use of the baro DA or the IM, whichever comes first. This is another option that must be included in the carrier's Op Specs.

In no case (that I am aware of) can a US operator use only the DA.

longobard
18th Dec 2010, 03:18
Will you insert the charted MDH value in the DH MCDU box in order to have the "AUTOCALLOUT FUNCTION" required on airbus to perform the CAT II approach??????

justanotheraviator
18th Dec 2010, 04:49
YMML ILS X Rwy 16 Cat II & III on my charts list an RA 93' for CAT II.

The chart is a tailored chart and dated 26 Nov 10.

PT6A
18th Dec 2010, 05:38
YMML is not a company airport for us, so our none tailored Lido chart shows RA93 for the CATII approach.

PT6A

longobard
18th Dec 2010, 10:55
so does anybody know if cat 2 approach minima can be baro-referenced?

Denti
18th Dec 2010, 11:29
Not if you fly under the regulations of EU-OPS, other regulations might see it differently.

9.G
18th Dec 2010, 12:56
longobard, the answer is YES it can be but only in conjunction with MM whichever comes first provided th OPS specs contain such provision etc... :ok:

aterpster
18th Dec 2010, 14:11
Manfield:

The use of the inner marker in this case is the standard procedure for US operators; however, it must be approved in that carrier's Op Specs. Not all carrier's programs incorporate this. If they do not, the approach is not authorized.

There was a time when a few operators that had done some modifications to their baro altimeters could fly to a 100-foot DA based on altimetry alone. But, those were "Jurassic" birds (727, DC-9, etc). I know my airline had that authorization but within a few years they installed radar altimeters. :)

Sir George Cayley
20th Dec 2010, 14:54
You won't find MMs and IMs in the UK. EGCC RWY 05L has a 25m deep valley in front of the threshold with the consequent Rad Alt problem.

Wonder how EU-OPS 1 operators deal with that?

Sir George Cayley

aerobat77
20th Dec 2010, 16:27
AFAIK in EU-OPS you must have a RA for CATII . inner markers are practical nonexistend here. more, the glideslope must be 3 deg.

so when the terrain may give irratic RA readings in the vicinity of DH or a steep approach is needed the airport will simply not have cat II or more.

the aircraft must be quipped with an radar altimeter and two indepentend autopilots which must be approved and functional.

on the bae146 we did catII approaches and there is a light "CATII green" which signals that both autopilots are tuned properly and crosschecking each other. otherwise you are CATI limited for the app.

PT6A
20th Dec 2010, 16:43
Sir George,

EU-OPS at EGCC for 05L, CAT B aircraft CAT I II & III authorised.

EU-OPS at EGCC for 05L, CAT C/D aircraft CAT I CAT III authorised CATII not authorised.



PT6A

Port Strobe
21st Dec 2010, 21:32
PT6A - never seen that before. Does that imply the faster aircraft in categories C and D have a higher OCH and this puts them slightly further back at a point where the terrain profile isn't acceptable for this purpose? That doesn't seem consistent though because all Cat II/III approaches have to transit over this terrain as well, any ideas??

Cough
22nd Dec 2010, 00:08
Manch 05L has a valley just prior to the threshold. I'm guessing, but the slower approach speed of the CAT B aircraft means the rad alt ramping is judged to be acceptable, but in the faster aircraft it is not.

9.G
22nd Dec 2010, 07:42
oddly enough MAN ILS 23R gives 2 mins both RA and DA for CAT II, explain that?

Port Strobe
22nd Dec 2010, 08:42
Cough

Thanks for the reply but what I was eluding to earlier was how can any approach be allowed to continue past a point where the rate of rad alt change is unacceptably high without adequate visual reference? The EK 380 flight has most probably been conducting a CatIIIB approach onto this runway over the last few days whilst still barely able to see their own nose, can't see why the rules would have to change just because that point in space coincides with the location of the DH for CatII? The AIP cites the "terrain profile" as the reason but gives nothing else away, I'm not saying you're wrong only that it seems inconsistent to me.