Missed approach tracking (Cairns ILS)
 

DAP chart says :

AIP says : So, if you make a missed approach 1/2 down the ILS, do you :
- immediately turn left without delay and track 015 (as per DAP chart)
or
- continue to track to the MAPT (as per AIP) before turning left to track 015 ?

The missed approach procedure begins at the missed approach point.

You would still track to the MAPt and then turn left (or however else a chart describes).


Would you follow a missed approach procedure before the MAPt on any other chart???? Probably not- CNS is thus no different.

Just remember the MAPt is for the LOC approach only (NPA). The ILS is a precision approach which uses the DA as the point by which visual reference must be established, not an MDA. The MAPt for an ILS is the point where the DA intersects the electronic GP. Therefore, if you conduct the the Missed approach prior to the DA on an ILS, you can't physically track to this point, you just fly what the chart says. In the case of Cairns, you turn left without delay to track 015, and intercept the 15 DME arc, climbing to 3700'. Thinking about it logically, there is some high terrain immediately to the south of the airport, so if you are discontinuing the approach you really want to turn left and get the f#ck out of there ASAP!

:ok:

If you turn left from half way down the localiser it causes all sorts of grief. The expectation is that you will fly to the dme point that coincides with the da and turn from there.

You don't just hang a left and bug out, you will put yourself on the 15 dme arc at a point that potentially puts you in conflict with other traffic.

Have a look at the CS RWY 33 LLZ plate. If you commenced the missed approach tracking before reaching the missed approach point, you could fly into some big hills. The reference in the AIP to commencing a missed approach means climb climb climb, you must still fly the MAP track as published on the DAP to ensure terrain clearance.
..unless ATC give you an amendment to the published.

Sydney is also a good example of where the missed approach track needs to be flown correctly, otherwise there may be all sorts of issues with conflicting traffic.

The RWY 33 LOC approach is not an ILS, it is an NPA, and so it's a requirement that you track to the MAPt before conducting the missed approach point. The ILS does not have a MAPt per se, and the procedure for the ILS says turn left without delay. Someone sugested you should track to the DME point which coincides with the glideslope and DA then turn left, but what if you don't have DME:sad:

Although thinking about it, you will have the marker beacons so you would track to the middle marker and then turn?

You need to consider WHY am I conducting a missed approach?

Take the blinkers off and consider navaid failure, (in particular LLZ) weather is not the only reason for a missed approach.

If it was a GS failure then there is no reason why you can't continue as per the LLZ approach. If it is a loc failure then use a bit of common sense, level out or begin climbing towards MSA, maintain heading and ask ATC what they want you to do. When they clear you for the ILS they expect you to fly along the centerline until the middle marker then either land or follow the missed approach. I can assure you that they will NOT be pleased when you suddenly spear off to the left into their departures!

On the other hand if unsure - don't hit the hill!:eek:

Because of what is published in the AIP :eek:

Let me quote the AIP again ENR 1.5 1.10.2 :

If I recall correctly, it used to say track to the OM and then without delay turn left blah blah blah.
I am aware of one occasion when a jet either had an onboard failure or the ground based aid failed, (cant remember) and he turned immediately.

Now not saying he did anything right or wrong, but shortly after, about a month or two, the procedure changed.

Perhaps you should research a little more before you fly off the handle there mr Fork. Term 3.10.2 and 3.10.5 directs the pilot to follow the approach procedure to the MAP and then follow the MA procedure. It also defines the MAP among other things as "the point of intersection of an electronic glide path with the applicable DA" and in almost every case this corresponds to the middle marker. So you MUST continue to track towards the runway and not turn left until arriving at the MAP.

If you turn left before this point then you are operating outside the requirements and regardless of how professional ATC are you will be penetrating their departures and will be reprimanded. I have seen this happen.

Yup! I know **** - no surprise in that!

"In the event that a missed approach is initiated prior to arriving at the MAP, pilots must fly the aircraft to the MAP and then follow the missed approach procedure. The MAP in a procedure may be:
a. the point of intersection of an electronic glide path with the applicable DA;"

Dr :8

PS: The moral of the story? Don't believe the crap that people write on Pprune!

Fortunately I fly 90% of ILS at YBTL and the Bo can outclimb Mt Louisa! :E

Let's suppose you adjust your DA to meet Missed approach climb req's OEI then Some light twins would have a MAPt back out near the OM.

Cs Approach tend to give departing aircraft assigned 030, so the missed approach tK 015 will keep you clear of departing aircraft, and the earlier it's initiated the more separation you will get.

I'm in the "turn as soon as it gets hairy" camp but welcome being proved wrong.

John,

A good question. How one works out the is anybody's guess; the profile table doesn't go down that low. Complicating matters is that you fly over the DME and out the other side before getting to the MM (0.5 DME south of the DME site - how would you set that up on your GPS, Doc?).

The logical answer would be to conduct conduct the MA at the MM ala the LLZ. If you're past the MM, do it immediately. Legally? Who knows. Methinks MAPs such as the one at CNS need more explanation.

The approach and subsequent missed approach are very carefully surveyed and designed to protect the aircraft from terrain provided the aircraft and pilot can meet the performance requirements. In the case of the ILS approach, the performance requirements are to remain within half scale deflection. The missed approach begins at the missed approach point and is based on 2.5% climb gradient as well as tracking and turning splays which are not spelled out in the AIP or on the chart. As I have already pointed out the missed approach point on an ILS is where the applicable DA intersects with the glide path. The applicalble DA in Cairns is 320 feet and that is basically the middle marker. The chart actually specifies the MAP is MM! This is how the approach is designed. If you increase your DA to meet the 2.5% you still need to track to the applicable DA missed approach point to remain within the surveyed approach. This applies to non precision approaches as well. If you turn off the approach early you will no longer be protected from terrain or other traffic.

The Cairns 9 departure heading ranges from 350 to 030 and west bound traffic generally overfly the ILS. If ATC expected that ILS traffic can turn left at any time then they would not clear any departures to the north or west while there was any inbound aircraft.

What would you do if you lost the loc outside 15 miles? The procedure says track 015 and fly along the 15 mile arc. Yiu will be tracking away from it in this case. Extreme I know but I'm simply following some of the 'logic' here.

I would love to hear from a Cairns ATC on this subject.

Oh no. If the departure was given 030, and the inbound was able to execute a left turn like a Pitts, then this may all be well and good.
However, the inertia of the inbound will take them well south of the 15 threshold in the MA, and if the departure has commenced their left turn well before the DER, then things get ugly. Likewise, the departure may have HDG 360 with TWR visually separating, and they would not be expecting the arrival making an early left turn.

Recently had a B717 go round off the ILS due to conflicting LOC indications. They turned left about 7DME, but advised they were doing so early. In this case, I can understand the reluctance to follow DAPs and the immediate advise allowed us to take other appropriate action.

If a MA is commenced early, then climb, advise ATC, and as soon as you're above RLSALT (or visual, if the problem isn't Wx related) we can initiate a turn as other traffic permits.

travelator - sounds like you've got a pretty good grasp of the issues involved.