NZHN approach observation and question

[Chairman]

I've been doing a few training hops from NZAA to NZHN, and have finally realised why all my approaches go quite as spectacularly wrong as they do. It's not me, it's the charts !

Here's what Mr Jeppesen has to say about the runway 18 VOR approach - slide on down 176 and thar she blows.



And here's a chart I downloaded from this page on aip about 5 minutes ago. Again, slide down 176 and Bob's your crossdressing Nana.



The trouble is, that when you DO slide down 176 expecting to see into the distance a ribbon of black stretching to the point of no turning back, you get this instead,



and while the runway may be marginally longer if you land diagonally instead of longitudinally, you just know it's going to end in tears. I finally found out why so many of my approaches ended in tears ...



It would be really really really nice if at least one chart had mentioned this tiny little offset, and said that once I could see the runway I needed to go left hand down a bit and actually line up with it ...

Is this what's it really like, are there any clues on the AIP chart about it that I'm not experienced enough to have picked up on, and what point should I think about doing the step to the left ?

Thanks
Gary

[Adamski]

I presume this is FS9? My FSX seems to make a *slightly* better job of it:




... and extending the centre-line ...


Adam.

[travnz]

Not every approach takes you straight in to the runway.
At hamilton none off the approach aids are inline with any runway

[Chairman]

Wouldn't a minor detail like "this approach does not leave you lined up with the runway" be mentioned somewhere on the approach chart ? It's a heck of a surprise to spring on some poor sod who's coming in on VFR minimums on his first visit to the airport ...

Gary

[travnz]

Well no, its a non precision approach. So one comes to expect that the approach isnt going to deliver you right to the runway. That is what the pilot is supposed to do after establishing visual reference to the runway.
Cant see the runway??
Execute the missed approach!

[Chairman]

Which takes me back to one of my original questions -

QUOTE

are there any clues on the AIP chart about it that I'm not experienced enough to have picked up on[/quote]

The NZHN chart is "VOR DME Rwy 18". Is it a reasonable precaution to assume that any approach not including a LOC or ILS may not leave you lined up for the runway ?

Gary

[mfraser]

As Travnz has already mentioned above, the approaches into Hamilton do not bring aircraft direct to the threshold. As a controller in the tower I always have to take into account the deviations from the extended runway centerline versus circuit traffic. The VOR and VORDME approaches aren't too bad, but the displacement on the NDB approaches is very pronounced (In fact the NDBDME 36 approach has the aircraft directly overflying the control tower!). It is normal to see IFR aircraft break visual late and 'jink' or 'dogleg' to end up on final approach. So you can be assured that what you're seeing in the sim is what happens in real life - albeit maybe not to the extent as shown in your screenshots!

[HardCorePawn]

You should try Tauranga sometime... you come in at about 15-20 degrees to the runway! Heading 089.. runway 074...

not quite so bad the other way... heading 244, runway 254...

As mentioned, the general idea is to get you (safely) to a point where you can see the runway and make a visual approach. If you're not visual by the decision point, you execute the go-around.

[SA227]

The only non precision approach that is likely to be lined up with the runway are the RNAV (GNSS) approaches. There are the odd exception like the RNAV for RWY 30 at NZKT which is slightly offset but generally the last waypoint will be the threshold or close to it.
The relationship of the runway to the approach is normally covered as part of the approach briefing. The other things to watch are 1) where the missed approach point is, which for runway 36 at NZHN is still the VOR, but at that point you're already past the runway!! And 2) the minimum altitude at the missed approach point is frequently above profile and can make a stabilized approach from the missed approach point to the runway impossible were you to go visual at the last second. Of course this is not an issue in flightsim

[A185F]

Even then some other RNAVs don't line up, Greymouth for one and I think Nelson too from mem. There quite a few VOR approaches in NZ which don't line up with the rwy, off the top of my head Nelson again and of course wellys, try keep flying down the 36 VOR app and see where you end up...

[HardCorePawn]

From memory, you're going to be explaining to your boss why you have a large hill sticking out the front of your aircraft!

aip.net.nz and GoogleEarth confirm it...

[atc_unit]

I suggest popping over to the VATNZ website and checking out Steve Halls non-precision approach tutorial. It may bring some light to the topic.

Link here: http://www.vatnz.net/cms/index.php?option=...6&Itemid=44

Enjoy.

[cowpatz]

As the name implies a No precision approach is exactly that....not precise. The only runway referenced approach aids are those associated with an ILS system, that being a localiser antenna at the upwind end of the runway and a Glidepath antenna adjacent to the touchdown area on the runway.
The words Precision and Non precision have now, in the main, been replaced by ILS or Non ILS approaches. Ideally the Non ILS ground based nav aid should be placed as near as possible to the centre of the runway. This would allow a fairly accurate approach to be flown. However many factors come into play such as:
Elevation, interference with transmission, signal reception on an arc about the aid (remember the aid may also have to cover approaches to other runways and the enroute navigation phase as well. In the case of Hamilton arrival tracks are from all directions, Terrain on the approach path (not withstanding the above, the aid is placed to allow for a minimum of manoeuvring to acquire the runway when visual as well as providing for the lowest possible met minima. A fan is drawn from the missed approach point back up the final approach course at various angles and the obstacles noted. The fan allows for tracking errors. The missed approach track (terrain). The final approach course will then be a compromise of all the above factors). The aid position may also affect holding altitudes. Of course with the advent of GPS approaches approach tracks can now be referenced to the runway and even have dog legs in the final approach course such as the RNAV 30 approach at Kaitaia. Unlike an NDB or VOR approach an RNAV, even if offset, will generally track to the threshold (if you extend it out).

It is good airmanship (and mandatory for multi crew airline pilots) to brief the approach taking particular note of the position of the aid in relation to the threshold and the effect that this will have on DME vs Altitude readings on the final approach course. You should also brief as to where you would expect to see the runway threshold, when becoming visual, giving due regard to the degree of course offset and crosswind (drift angle). No point in looking dead ahead if the aircraft is drifting 10 degrees and the final approach course parallels the runway to some degree (as in Hamilton). In poor conditions you could miss sighting the threshold altogether or spend too long looking at the expense of attending to controlling the aircraft

[Chairman]

Interesting thread, thanks to everyone who's contributing.

From a basic simmers point of view, would it be fair to summarise this as "if an approach doesn't have ILS or LOC in the title don't expect it to leave you lined up with the runway, and this probably won't be noted on the approach chart (although if the final approach course doesn't equal the runway heading that's a giant economy family sized clue)" ?

Thanks
Gary

[travnz]

Also if the approach doesnt stipulate a runway to be used, also assume that you are going to circle to land.

[mfraser]

And just in time to add weight to the discussion, the CAA have released some information and advice regarding IFR circling approaches in the latest issue of Vector Magazine - Issue Sept/Oct 08. Back issues in PDF format are able to be viewed here although this issue is not online as yet.

CAA Vector Magazine Back Issues Online

The article states in the first paragraph - "A straight in approach is where the centreline of the runway you will be landing on is straight ahead of you at the end of the instrument approach. This will be within +/- 30 degree's for Category A and B aircraft, or within +/- 15 degree's for Category C and D aircraft."

So there you have it, words written in blood from New Zealands aviation regulatory body!! As Travnz has just said - and advice from me as an Air Traffic Controller - pilots should never make an assumption that a landing will be made off the approach. For whatever reason, ATC may require the aircraft go around and make a visual circuit, or make a circling approach (As stated above), or intercept the standard missed approach!

[HardCorePawn]

Beaten!

I was reading this article last night and thinking... "I should post that bit about the approach being +/- 30 Degrees for Cat A/B and +/- 15 for Cat C/D"...

So technically the Tauranga approach is "straight in"...