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NO Instrument App/NO TAF - Alternate ?

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NO Instrument App/NO TAF - Alternate ?

Old 25th Oct 2020, 01:34
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NO Instrument App/NO TAF - Alternate ?

G'day aviators, I have recently found myself unemployed from Emirates after 14 years, (A380 skipper), and I am am studying the "world's best practice" (tongue in cheek) Aussie AIP. I did a search this topic here, but the results were confusing and nearly 10 years old. So I thought I would ask the experts here for confirmation.

Scenario -

I am flying IFR charter to Woop Woop and it does not have a navaid, nor does it have a published approach procedure. It does not have a TAF. It is a gin clear day.

Question DO I need an alternate?

My understanding (interpretation) is that I DO need one. Am I correct?

Cheers n beers even in Algiers



Capn Rex Havoc is offline  
Old 25th Oct 2020, 01:43
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By day, an alternate IS NOT required to a non IAP destination if the the weather is greater than LSALT +500ft and 8km visibility for the final route segement. ENR 1.1 -11.7.2.12 and ENR 1.10

By night, an alternate is always required for a non IAP destination ENR 1.10 pg. 3

Does this make sense?
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Old 25th Oct 2020, 02:15
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Thanks mmm345,

Under the AIP - Alternates section (11.7)
it says as its first point under ~General (11.7.1.3) "When an aerodrome forecast is not available .... PIC must make a provision for a suitable alternate"

Then the the other sections go in to Weather conditions and Nav Aids.

So I reckon the starting point is you need a TAF, lest you need an alternate.
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Old 25th Oct 2020, 03:05
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The interpretation of that reference i believe is based around an aerodrome in which a TAF is normally available however is unavailable or is desingated as PROV ( provisional), which both require an alternate. However, my understanding is that this regulation is NOT applicable to an aerodrome in which a aerodrome forecast ( TAF) is not normally available IE.many small regional ports.

See ENR 1.10 -1.2.1, when planning to a non IAP destination, the minimum forecast is a GAF.

Anyone else have a different interpretation of these regs?
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Old 25th Oct 2020, 03:21
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First a disclaimer, my airline has its own, more conservative procedures therefore I’m not as fluent with the AIP as I once was, however I understand the bolded section from ENR1.10 below covers the above scenario re no TAF at destination:

1.2 Forecasts
1.2.1 Forecast information must include:
a. an aerodrome forecast for the:
(i) destination; and
(ii) when required, alternate aerodrome; and
b. one of the following:
(i) a flight forecast; or
(ii) a GAF (at and below A100); or
(iii) a SIGWX forecast (above A100); and
c. a wind and temperature forecast
For a flight to a destination for which a prescribed instrument approach procedure does not exist, the minimum requirement is a GAF.

(mmm345, sorry it looks like you responded as I was typing my response. I agree with your interpretation that a GAF is sufficient, therefore allowing flight to destination without an alternate provided VMC can be maintained over last route segment)
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Old 25th Oct 2020, 06:21
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Also, I have a recollection that you require QNH from a source within 100Nm but I can't find it - am I correct?
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Old 25th Oct 2020, 06:25
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Originally Posted by mmm345 View Post
The interpretation of that reference i believe is based around an aerodrome in which a TAF is normally available however is unavailable or is desingated as PROV ( provisional), which both require an alternate. However, my understanding is that this regulation is NOT applicable to an aerodrome in which a aerodrome forecast ( TAF) is not normally available IE.many small regional ports.

See ENR 1.10 -1.2.1, when planning to a non IAP destination, the minimum forecast is a GAF.

Anyone else have a different interpretation of these regs?

I would say an alternate is required anywhere there is no TAF (both VFR & IFR).

Unless it has changed, the requirement was that if an aerodrome as a TAF that is PROV (provisional) then an alternate is ALWAYS required (even on a perfect CAVOK day). If you extrapolate that requirement, then one would expect that if there is no TAF at all then an alternate is required as well.

Last edited by mikewil; 25th Oct 2020 at 06:46.
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Old 25th Oct 2020, 06:48
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Originally Posted by mmm345 View Post
By day, an alternate IS NOT required to a non IAP destination if the the weather is greater than LSALT +500ft and 8km visibility for the final route segement. ENR 1.1 -11.7.2.12 and ENR 1.10

By night, an alternate is always required for a non IAP destination ENR 1.10 pg. 3

Does this make sense?
Correct.....
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Old 25th Oct 2020, 09:30
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Hi mmm345 -
when planning to a non IAP destination, the minimum forecast is a GAF.

Anyone else have a different interpretation of these regs?
The GAF minimum is in the Forecast section - not the Alternate section, so, to my reasoning, when talking about Alternate requirements - you need to look at the contents of 11.7..

and mikewill
I would say an alternate is required anywhere there is no TAF (both VFR & IFR).
I agree with you mikewill. No TAF = Alternate.

From an airmanship perspective, I reckon that makes sense. I reckon if you don't know what is going on at an airfield you are launching to - eg possibility of fog etc, best you have an ace up your sleeve like an alternate that has a TAF.

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Old 25th Oct 2020, 10:03
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Also from an airmanship point of view, airfields can be unusable for other reasons than weather. What would you do if as you were approaching your destination in VMC, an aircraft ahead of you burst a tyre on landing, blocking the only runway? You would be glad if you had researched an alternate then.
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Old 25th Oct 2020, 10:35
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Also from an airmanship point of view, airfields can be unusable for other reasons than weather. What would you do if as you were approaching your destination in VMC, an aircraft ahead of you burst a tyre on landing, blocking the only runway? You would be glad if you had researched an alternate then.
That is true, but that sort of thing is not in the AIP - where as NO TAF = Alternate is.

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Old 25th Oct 2020, 10:36
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I think we are talking small IFR charter aircraft. You can land anywhere. Lots of strips in Australia if your mate blows a tire!
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Old 25th Oct 2020, 10:56
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Originally Posted by PaulH1 View Post
Also from an airmanship point of view, airfields can be unusable for other reasons than weather. What would you do if as you were approaching your destination in VMC, an aircraft ahead of you burst a tyre on landing, blocking the only runway? You would be glad if you had researched an alternate then.


Do you plan for everything,,, what if your going to your alternate(single runway) and the plane in front of you bursts a tyre and blocks the runway?
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Old 25th Oct 2020, 11:08
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There comes a point where you wouldn't even get out of bed to do a flight if you tried to cover every scenario!. Apart from the legal requirements as mentioned here one has to way up the risks & apply them on an individual flight basis. I used to drive out to Island dromes in the middle of the night in the middle of the Pacific with all the 'legal' requirements complied with BUT there was plenty of other associated risks that I managed that weren't in the book, a plan B is mandatory even for a basic flight.
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Old 25th Oct 2020, 11:09
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By night, an alternate is always required for a non IAP destination ENR 1.10 pg. 3
If you're over 5700kg, this is incorrect. You're not allowed plan it. ENR 1.10 1.5.1.
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Old 25th Oct 2020, 11:13
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I agree with you that from an airmanship perspective, in a potentially marginal weather situation or whether you believe the GAF might not be a true reflection of the weather, it would be a very wise to carry an alternate.

However, this make no sense when considered from what a VFR aircraft can do.

"When an aerodrome forecast is not available or provisional, the PIC must make provision for a suitable alternate that has a firm forecast."

This from the AIP doesn't distinguish between IFR and VFR. If that was the case that if planning to an AD that doesnt have a TAF you must require an alternate, VFR aircraft wouldn't be able to fly to any old airport that doesn't have a regular forecast without an alternate, which as we known isn't what happens legally. If a VFR aircraft in a CAVOK day, as seen visually and from the the area forecast can fly to a non- TAF aerodrome without an alternate, why cant a IFR aircraft, both aircraft are in the exact same weather conditions ( CAVOK).

Secondly, the AIP quote about requiring an alternate for TAF unavailable airport begins with " For aerodromes with an Instrument Approach Procedure". Evidently, this rule doesnt apply to an aerodrome without an IAP as this rule is in relation to being able to determine alternate requirements based upon the alternate minima published on the IAL chart.

Thirdly, Why would the AIP publish the Alternate Minima for a non IAP destination to be " LSALT+ 5 and 8km for the last route segment". Nearly always, the last route segment wont be contained within the capture region of an Aerodrome forecast ( 5nm of ARP), thus the GAF comes into play.

The note about a forecaast being unaviable or provisional is under my understanding to be in regards to being outside a TAFs validity period ( thus making it unavailable for planning) or other factors that cause a normally issued TAF to not be valid/available .

In summary

ENR 1.1: For aerodromes without an IAP, the alternate minima is LSALT + 500ft for final route segement and 8km vis

ENR 1.10 For a flight for which a IAP does not exist, the minimum requirement is a GAF

Why would you require a TAF to avoid alternate if it states that for a non IAP destination, the minimum is a GAF ( for the sole reason that you don't need to compare Aerodrome weather with the alternate minima on the chart).

Since there is no IAP chart, you establish the final routes LSALT, add 500ft and consult the GAF, if there is more than SCT cloud below the minima you just established, you provide an alternate.

Why should a VFR aircraft be able to fly to a non - TAF destination without a alternate, as they have looked at the GAF ( which is the minimum ENR 1.10) and out the window and its blue skies everywhere, whilst a IFR aircraft must carry an alternate whilst flying in the exact same weather conditions...?

And to re-instate the non IAP destination requirements, by day you need not have an alternate if LSALT+5 and 8km vis for last route segment, ( as will be able to conduct a visual approach), but by night require an alternate regardless.

Dont get me wrong, if its very marginal weather outside or i doubt the GAFs accurarcy or by knowledge of local weather conditions prevailing, an alternate will be very good idea.

However, I dont agree or see how an IFR aircraft must have an alternate simply because there is no TAF, however a VFR aircraft looking at the same blue skies can happily plan to the same airport without alternate fuel.

​​​​​​​



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Old 25th Oct 2020, 11:37
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mmm345,

This is cut and pasted directly from the Airservices Australia VFRG -As pilot in command, you must make provision in your pre-flight planning for an alternate aerodrome if:
  • you plan to arrive at your destination:
    • 30 minutes before the commencement of
    • during or
    • 30 minutes after the end of the validity period of a forecast that indicates meteorological conditions that are below alternate minima or
  • if the forecast for the destination is:
    • not available or
    • is attached with the term ‘provisional’.
The VFR alternate minima are as follows:
  • for aeroplanes:
    • a cloud base that is SCT with a ceiling of 1500 ft
    • 8 km visibility; and
If I am to read the above format similar to an airbus checklist, those dot points make it pretty clear that if you don't have a TAF then you MUST have an alternate.





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Old 25th Oct 2020, 12:23
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Whilst this is quite a confusing topic ( from what i can see this isnt the first thread of the topic and head is starting to hurt alot), the AIP states multiple points to suggest that for a non IAP destination with no TAF, no alternate AD is required if GAF shows can maintain LSALT+500ft and 8km on final route segment.

Namely, ENR 1.1-92 refers to the clause about " Where the TAF is unavailable" ( potentially using language that implies that this clause refers to destinations where a TAF is normally available"- begins with " For AD with an IAP", the question of this thread is in regard to a negative IAP aerodrome.

Clause C of ENR 1.1-92 refers to the question of this thread, for " AD without an IAP".

Additionally, in ENR 1.10, it states that when an IAP does not exist at an AD- the minimum forecast required is a GAF, why would they say this if you need an alternate if you dont have a TAF.

The unavialbility of a normally published TAF is only a factor at an aerodrome with a published IAL. The TAF would be used in the planning phase to align with the alternate minima on the chart and thus determine alternate requirements.

At a non IAL chart destination, there is no published alternate minima on the chart to match the weather on the TAF with. Thus, the AIP states that you must conisder the LSALt on the final route segment , add 500ft and enter with a visbility of 8km. Consult the GAF ( as the TAF is null and void outside of 5nm ARP) and determine alternate requirements from this. The TAF for such a destination without an IAP would be useless ( although handy for SA) for planning alternates as 99% of the time the final route segment will not be within 5nm of the destination and thus requires consult of the GAF anyway.
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Old 25th Oct 2020, 14:03
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"11.7.3.2 Notwithstanding the above, a flight may be planned under the IFR by day to a destination aerodrome which is not served by a radio navigation aid without the requirement to provide for a suitable alternate aerodrome, provided that
a. not more than SCT cloud is forecast below the final route segment LSALT plus 500FT and forecast visibility at the destination aerodrome is not less than 8KM; and
b. the aircraft can be navigated to the destination aerodrome in accordance with para 4.1"
Taken with the aforementioned flight planning requirement:
"For a flight to a destination for which a prescribed instrument approach procedure does not exist, the minimum requirement is a GAF."
....then I would agree with mmm345 that in the specific scenario of the OP, an IFR dispatch by day without an alternate is legal based on a GAF only.
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Old 25th Oct 2020, 14:21
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Originally Posted by mmm345 View Post
Whilst this is quite a confusing topic ( from what i can see this isnt the first thread of the topic and head is starting to hurt alot), the AIP states multiple points to suggest that for a non IAP destination with no TAF, no alternate AD is required if GAF shows can maintain LSALT+500ft and 8km on final route segment.

Namely, ENR 1.1-92 refers to the clause about " Where the TAF is unavailable" ( potentially using language that implies that this clause refers to destinations where a TAF is normally available"- begins with " For AD with an IAP", the question of this thread is in regard to a negative IAP aerodrome.

Clause C of ENR 1.1-92 refers to the question of this thread, for " AD without an IAP".

Additionally, in ENR 1.10, it states that when an IAP does not exist at an AD- the minimum forecast required is a GAF, why would they say this if you need an alternate if you dont have a TAF.

The unavialbility of a normally published TAF is only a factor at an aerodrome with a published IAL. The TAF would be used in the planning phase to align with the alternate minima on the chart and thus determine alternate requirements.

At a non IAL chart destination, there is no published alternate minima on the chart to match the weather on the TAF with. Thus, the AIP states that you must conisder the LSALt on the final route segment , add 500ft and enter with a visbility of 8km. Consult the GAF ( as the TAF is null and void outside of 5nm ARP) and determine alternate requirements from this. The TAF for such a destination without an IAP would be useless ( although handy for SA) for planning alternates as 99% of the time the final route segment will not be within 5nm of the destination and thus requires consult of the GAF anyway.
Agree completely with mmm345. As stated by someone else it does not apply at night for >5700.

Also, I always have a peek at the GAF when considering fuel loads even when there is a TAF as GAFs by definition are way more conservative. Criteria for inclusion of phenomena on the TAF is minimum 30% probability vs 10% on the GAF, and is not restricted to the 5nm fishbowl surrounding the aerodrome. It's very common to see TS on the GAF for the area around Darwin, but not on the TAF or TTF. The storms on these days sometimes ignore the Berrimah line.
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