Non Precision Approaches in NZ
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Non Precision Approaches in NZ
Hurro,
just curious why some of the kiwi approaches, i.e. VOR/DME18 at NZRO have a timed outbound, however a DME monitored inbound? why not use a DME outbound, doesnt appear to be terrain issues off the 356 radial for the DME signals. Also the same thing is noted with the NDB/DME18 at NZHN. The issues that come up are when you have a headwind on the outbound (happens with kiwi wx sometimes) therefore after you reach the time you can turn inbound before the FAF. Bugger, missed approach time
One also cant time adjust when indicating over 110kts . Any thoughts on why they designed approaches like this?
just curious why some of the kiwi approaches, i.e. VOR/DME18 at NZRO have a timed outbound, however a DME monitored inbound? why not use a DME outbound, doesnt appear to be terrain issues off the 356 radial for the DME signals. Also the same thing is noted with the NDB/DME18 at NZHN. The issues that come up are when you have a headwind on the outbound (happens with kiwi wx sometimes) therefore after you reach the time you can turn inbound before the FAF. Bugger, missed approach time
One also cant time adjust when indicating over 110kts . Any thoughts on why they designed approaches like this?
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Well with NZRO. The VOR/DME approach has a lower MDA than the stand alone VOR 18 app of 1700 which is on the backside of the coupled approach.
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The issues that come up are when you have a headwind on the outbound (happens with kiwi wx sometimes) therefore after you reach the time you can turn inbound before the FAF. Bugger, missed approach time One also cant time adjust when indicating over 110kts
The only thing to do is, go like you stole it on the outbound leg for the maximum allowable time and bring the speed back to the minimum safe on the inbound.
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"Crazy approach" about sums it up.
It's said above (correctly) that you can't extend outbound if going above 110kts. Again, crazy. Why doesn't the AIP just quote PANS-Ops on this one?
As to turning inside the FAF - simple answer, don't. Regardless of the time, if you have a DME, don't turn inside the FAF or you'll likely end up unstable. That's much less safe than going to 6DME, regardless of the time.
Good old Airways. They get it right most of the time anyway.
It's said above (correctly) that you can't extend outbound if going above 110kts. Again, crazy. Why doesn't the AIP just quote PANS-Ops on this one?
As to turning inside the FAF - simple answer, don't. Regardless of the time, if you have a DME, don't turn inside the FAF or you'll likely end up unstable. That's much less safe than going to 6DME, regardless of the time.
Good old Airways. They get it right most of the time anyway.
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yeah just kinda sucks having to teach these approaches to students. And the training being done at Cat B speeds therefore ruling out the 110kt adjustment. But i just say airmanship, at 3 mins, not past the FAF continue tracking until DME ticks past the FAF.
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Asked a similar question a while ago...this is the answer I got from "one in the know"....
Clear as mud??
(NB Asked the question back in FEB 07 so the quoted plates may have moved on since then!)
The answer is not simple. Where a DME dependent approach has a DME limiting base turn this figure is shown on the plan graphic. Example Tauranga NDB/DME RWY 07 where 7 DME is shown on the plan graphic. A distance figure is not shown on the plan graphic for the NDB/DME RWY 25 approach so time only applies when flying the base turn.
The 7.3 DME annotation is the distance at which an aircraft at 2000ft will intercept the 2.9° (5%) descent angle and is not the limiting distance for flying the base turn procedure.
I accept it is confusing and this is an issue that the chart standards working group is trying to overcome. Introducing constant angle descent profiles (AIC 5/05 refers) looked easy at first but there are some fish hooks. The Tauranga NDB/DME RWY 25 approach was one of the early charts changed and I believe is to be amended again.
Why a DME dependent approach has outbound timing and not distance is one I can't answer.
The 7.3 DME annotation is the distance at which an aircraft at 2000ft will intercept the 2.9° (5%) descent angle and is not the limiting distance for flying the base turn procedure.
I accept it is confusing and this is an issue that the chart standards working group is trying to overcome. Introducing constant angle descent profiles (AIC 5/05 refers) looked easy at first but there are some fish hooks. The Tauranga NDB/DME RWY 25 approach was one of the early charts changed and I believe is to be amended again.
Why a DME dependent approach has outbound timing and not distance is one I can't answer.
Clear as mud??
(NB Asked the question back in FEB 07 so the quoted plates may have moved on since then!)
Last edited by slackie; 28th Jun 2008 at 21:13. Reason: speling!
Another point.
Why the change to the inbound profile on non precision approaches from the old 300'/nm (5%) to the 5.2% (320'/nm) gradient.
Yes, the new profile might be technically the correct one but it's a f**k sight easier to work out 3 times the distance plus/minus correction in your head than it is to do 3.2 times distance plus/minus correction to check your profile as you fly the approach.
The old 300'/nm certainly made for less worklaod on the approach and there was almost no need to keep referring to the plate to check your profile.
The new system sucks and obviously designed by people who never use the plates they design.
The old system was practical and it worked why change it?
Sorry for the thread drift.
Why the change to the inbound profile on non precision approaches from the old 300'/nm (5%) to the 5.2% (320'/nm) gradient.
Yes, the new profile might be technically the correct one but it's a f**k sight easier to work out 3 times the distance plus/minus correction in your head than it is to do 3.2 times distance plus/minus correction to check your profile as you fly the approach.
The old 300'/nm certainly made for less worklaod on the approach and there was almost no need to keep referring to the plate to check your profile.
The new system sucks and obviously designed by people who never use the plates they design.
The old system was practical and it worked why change it?
Sorry for the thread drift.
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Ill second that 27/09....
The 300' per NM was much easier to deal with on a NPA than what we have now with a 6DME height of 1827ft, 5DME 1493ft etc etc
Its just thrown one more distraction into SPIFR ops at the least.
It wasnt broken in the first place so why not leave it alone.
The 300' per NM was much easier to deal with on a NPA than what we have now with a 6DME height of 1827ft, 5DME 1493ft etc etc
Its just thrown one more distraction into SPIFR ops at the least.It wasnt broken in the first place so why not leave it alone.
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Another thread drift
I was only enlightened recently that the outbound portion of the tear drop is considered by PANS OPS to be a reversal procedure and limited to IAS 140kts by Cat B aircraft.
So all AirNZ Link turboprops which are considered Cat B may soon be recategorised as Cat C, as flying for 7-8Nm at 140kts outbound is gonna be a bunch of arse (except AirNSN at the mo who'll probably love that development)
Check out Figure ENR 1.5-6 diagram c for depiction of the tear drop / base turn.
Turns out my previous understanding of the outbound and base turn were considered the "initial approach" segment until either established on the final approach path or cross the FAF (if depicted) to then be on Final Approach is
now not up to speed (pun)
Get that one around your heads
S2K
So all AirNZ Link turboprops which are considered Cat B may soon be recategorised as Cat C, as flying for 7-8Nm at 140kts outbound is gonna be a bunch of arse (except AirNSN at the mo who'll probably love that development)
Base Turn
4.13.4 A base turn consists of a specified outbound track and timing from a
facility, followed by a turn to intercept the inbound track.
4.13.4 A base turn consists of a specified outbound track and timing from a
facility, followed by a turn to intercept the inbound track.
Turns out my previous understanding of the outbound and base turn were considered the "initial approach" segment until either established on the final approach path or cross the FAF (if depicted) to then be on Final Approach is
now not up to speed (pun)
Get that one around your heads
S2K
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PANS OPS is only a basis/reference to approach design i thought? Therefore hence why Cat B is 120-180kts for the initial app (outbound & baseturn). From what i understand, the Link props fly the Cat C approaches, i know eagle does this, except into WR.
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From what i understand, the Link props fly the Cat C approaches, i know eagle does this, except into WR.
Mt. Cook use Cat B and C as required but generally work on the premise that the ATR is a Cat B aircraft. I've heard they are going to get it re-categorised as C because in a lot of conditions i.e. icing & high landing weights the min approach speed can very close to or even be higher than the max speed for Cat B Final Approach and Circling speeds.
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Because the good folk at Airways haven't produced an instrument approach plate which has been designed for Cat C aircraft into WR.
