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PART 121 Alternate requirements OZ

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Old 1st Jul 2023, 02:08
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PART 121 Alternate requirements OZ

Hi All

Can someone help me with a few questions ?

- Is the special alternate minima still available under 121 ops? It's not mentioned in the MOS but remains in AIP?

- are 2 crossing runways ie. YMML considered separate runways ?

thanks for input.
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Old 1st Jul 2023, 03:35
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1. No. Alternate minima is calculated from requirements in Part 121 MOS

2. Yes. They are two physically separate runways. How you decide to interpret that in your own operation is up to you though. Eg. Old mate rejecting and stopping at the cross of both runways.
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Old 1st Jul 2023, 04:05
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Originally Posted by transition_alt
1. No. Alternate minima is calculated from requirements in Part 121 MOS

2. Yes. They are two physically separate runways. How you decide to interpret that in your own operation is up to you though. Eg. Old mate rejecting and stopping at the cross of both runways.
Plan to use YMAV/YMEN and then use YMML as an alternate, no 15 minute final reserve, lower required minima that's below the old special alt minima. Divert once within 1 hour of the destination and continue based on the lower minimum required. Only problem is you will get screwed over by the slot system and get sent to the back of the queue for that arrival time...

You can use other methods like depart using an en-route alternate and re-plan using the 1 hour flight time/TAF3 rule to continue to YMML.

If it's part 121 your ops manual will tell you what you can do... If you are writing a part 121 ops manual, put whatever you want in there, the pilots will get confused in any case, and hopefully they carry enough fuel so your arse isn't called on in the investigation, good luck!
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Old 1st Jul 2023, 08:27
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Thanks all. Any further discussions on this welcome.
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Old 1st Jul 2023, 09:34
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PAL

Another question please

Night flight

If my alternate airport has PAL and stby power. If no responsible person is it correct i cannot use this as a alternate?

Thanks All
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Old 1st Jul 2023, 09:43
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All PAL setups need a responsible person present to switch the lights on manually (or display Portables) if there is a failure of the radio system, regardless of destination or alternate. The only relief, for alternates only, and a certain range of aircraft (non part 121) that have 2 x VHF or VHF + HF and 30mins fuel etc... or you carry enough fuel for first light +10 minutes.

Standby power is the one that can be omitted in certain circumstance for alternates, if the alternate was required due to standby power availability or PAL. Remember if you needed the alternate due to weather or navaids before lighting then you still need standby power at the alternate.

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Old 1st Jul 2023, 10:46
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Originally Posted by Bringanotherengine

- are 2 crossing runways ie. YMML considered separate runways ?.

27 and 09 are different runways

16L and 16R are separate.

34 LAHSO and 27 could be considered separate.
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Old 1st Jul 2023, 10:52
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Originally Posted by 43Inches
If it's part 121 your ops manual will tell you what you can do... If you are writing a part 121 ops manual, put whatever you want in there, the pilots will get confused in any case, and hopefully they carry enough fuel so your arse isn't called on in the investigation, good luck!
As much as we love to rage at the vkusterfyck of the regulatory reform, the Part 121 alternate requirements aren’t actually that bad and are an ICAO international standard. it’s the CASR that drives you to the MOS that’s the problem.

It all goes nicely in a flow chart BTW.
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Old 1st Jul 2023, 12:27
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Originally Posted by compressor stall
27 and 09 are different runways

16L and 16R are separate.

34 LAHSO and 27 could be considered separate.
The best example I’ve seen to explain this part 👌🏽 Well done Compressor Stall!
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Old 1st Jul 2023, 23:23
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34 and 27 are definitely considered separate, LAHSO is just normal operations term, if something crashed on the intersection I'd say the hold short line would be way to close for comfort for the EMTs working there, and it's not designed for a persistent blockage of the crossing point. If you really want to get pedantic about the separation you could claim 16/34 operational length to be 2500 only using the portion south of the intersection. If your Jet cant stop in that distance you have other problems, go to Avalon. If you want to know how these laws are written with small risks unaccounted for then look no further than LAHSO, which had no provision for a double go-around with the runway occupied....

I've flown into Melbourne where the Airport has closed for several reasons, lighting failures, tower evacuations, animals running around the runways, VP/VIP arrivals, with no advanced warning, and whats worse the controllers had no idea what to do apart from hold everything in situ and wait for pilots to decide to divert... Do not assume they have solid contingencies for anything other than the staple aviation things... Never go there with minimum holding...
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Old 1st Jul 2023, 23:49
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Thanks all

If using a TAF 3 and using the reduced mins in table 4.11. Is it correct you basically need to be arriving within 2 hrs of the issue of the TAF in order to have to forcast valid 30 before and 60 after ? Seems only short flights would benefit from taf 3 use for alternate planning ?

item 1 of the 4.11 chart says "atleast 1 approach procedure has an available cat II or cat III minima. Does this mean you need to be able to use this approach type as it says available. Ie. Im flying to ymml but im only cat 1 approved.

Thanks all.
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Old 2nd Jul 2023, 00:02
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If using a TAF 3 and using the reduced mins in table 4.11. Is it correct you basically need to be arriving within 2 hrs of the issue of the TAF in order to have to forcast valid 30 before and 60 after ? Seems only short flights would benefit from taf 3 use for alternate planning ?
That's the general interpretation, and I assume that statement was included based on the issue frequency of the old TTF, as TAF3 can be up to 3 hours apart if conditions are not changing. So you might never get a window to use the TAF3 depending on arrival time. BOM aims for the first 5 hours to be accurate and up to date, yet CASA only allow the first 3 hours to be used. The TAF3 should mandate an issue every 30 minutes when conditions hit SPECI criteria.

That being said, watch for Fog conditions, the Met officers in Australia seem to be blind to it until it actually rolls in on the airport and shuts down operations. Even in the last 6 months there has been a few occasions when fog 'suddenly' appeared and aircraft with minimum fuel had to divert en-route. ('suddenly' being defined as it was hanging around the edges of, or approaching the field and no one thought to put a warning on the forecast until a pilot goes around or reports it). I also wonder whether the reluctance to put fog on forecasts is a commercial pressure, in that last minute fog forecast for internationals that are on the last 3 hours of their flight might cause diversions etc.... So they don't do it until it actually occurs.

Always come back on the Captain that must be "familiar with the route to be flown including local weather patterns and conditions".

All this being said I suggest you chat this through with your 217 department, if you are flying for a part 121 operation, as these are the basic fuel requirements and a company will have type specific and company specific alterations that need to be addressed.

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Old 2nd Jul 2023, 00:18
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Originally Posted by 43Inches
34 and 27 are definitely considered separate, LAHSO is just normal operations term, if something crashed on the intersection I'd say the hold short line would be way to close for comfort for the EMTs working there, and it's not designed for a persistent blockage of the crossing point. If you really want to get pedantic about the separation you could claim 16/34 operational length to be 2500 only using the portion south of the intersection. If your Jet cant stop in that distance you have other problems, go to Avalon. If you want to know how these laws are written with small risks unaccounted for then look no further than LAHSO, which had no provision for a double go-around with the runway occupied....
34 inches - I'm not sure if you're playing semantics but separate runways are only separate if there is sufficient runway remaining for you after the closure of the other runway. MOS 121 refers in multiple places.

The reason I used the LAHSO example was (perhaps too subtly) to outline that if an aircraft had a wheels up on 34 and left stuff strewn all the way to the north end closing 34, you won't have much luck landing on 27 (unless you fly 172 in there?) ergo, they are not always separate.
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Old 2nd Jul 2023, 00:31
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Originally Posted by compressor stall
34 inches - I'm not sure if you're playing semantics but separate runways are only separate if there is sufficient runway remaining for you after the closure of the other runway. MOS 121 refers in multiple places.

The reason I used the LAHSO example was (perhaps too subtly) to outline that if an aircraft had a wheels up on 34 and left stuff strewn all the way to the north end closing 34, you won't have much luck landing on 27 (unless you fly 172 in there?) ergo, they are not always separate.
Turbo props could definitely use 27/09 as there's plenty of runway in a max performance landing. Remembering the aiming point for everything non-A380 is the second markers, not the 'fat boys', otherwise you need to remove approximately 150 mt from your landing distance available as the TCH is around 70 feet. They actually did consider 27 for LAHSO as it would be similar distance to LAHSO they had at Adelaide. You have about 1200 mtrs either side of the intersection. The DASH and SAAB can make A easily if you use the brakes, V you can even roll a bit now. I always laugh when 737s cant make N then a Heavy makes it with room to spare, even saw a 717 miss it the other day...
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Old 2nd Jul 2023, 00:36
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Sure - fine for a SAAB. - but turboprop performance isn't going to help you in a B737.

One man's different can be another man's separate.
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Old 2nd Jul 2023, 00:43
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Well yes, plus the fact you have to actually take into account wind and actual available navaids now as well, not a generic all encompassing alternate minima that only increased with multiple navaid failure. That being said you could hold Avalon for not much more fuel as you lose the 15 minute final reserve,depending on your companies fuel policy. You'd have the same issues for Perth with less alternates available. If not tanker up for Adelaide/Canberra or Sydney, or Mildura if you dare...

Thats where it gets complicated, as if the wind is favoring 16 but 27 is out, you wont even be able to use CAT I minima... not even SI NPA it will be circling minima restriction only, which is the norm for 16 north end works.

What throws a spanner in the works of what ifs 'if' you want to take it that far, is that 'if' the aircraft crashes on 16/27 and slides towards the tower complex the tower will be evacuated and standard procedure is to close the airspace for an OMG what happened period of time so its all academic... hence if you really want to allow for catastrophes then just carry an alternate. The runway could even be destroyed by an earthquake these days, who knows, Mt Holden next door is an old volcano, so should we take that into account... but yes, straying from part 121 requirements a bit.

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Old 2nd Jul 2023, 00:54
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If using say Mildura as alternate for YPAD(at night) I would assume this can't be done as YMIA does not have a responsible person for PAL or does it? How to know this. ?

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Old 2nd Jul 2023, 01:02
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Originally Posted by Bringanotherengine
If using say Mildura as alternate for YPAD(at night) I would assume this can't be done as YMIA does not have a responsible person for PAL or does it? How to know this. ?
If you are part of a 121 organisation it is up to the company to organize that on behalf of the crew, PIC is still responsible to make sure it's available though before you depart. Some airports the ARO agrees to be available with a phone call, others they have local staff, if we are talking a 737 or bigger then you WILL need some form of ground staff and possibly an agreement to use other operators ground equipment, unless you have some form of airstairs installed on your jet. Never assume somebody will be available, other airlines cancel, their staff go home, AROs can have a drink after hours so if they are not on standby you cant expect them to suddenly drive to the airport at midnight without prior notice and so on....

That being said I've heard of several occasions where lights failed. One being a lightning strike on a light, which destroyed the mains box and the standby power. Another the maintenance works forgot to switch the PAL receiver back on, and locked the access box before leaving for the night. And a few others with varying normal reasons like PAL receiver failures that were switched on by ground staff.
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Old 2nd Jul 2023, 01:11
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Thanks for the info all. Appreciate it.
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Old 2nd Jul 2023, 10:12
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I used to summarize all the requirements as: can you guarantee a safe result, even when something (anything) goes wrong? It's never stated, but that's the basis of IFR ops - no guarantee of getting to your destination, but you have to be sure you always have a safe plan B.

Lighting fails - plan B - can safely go elsewhere. Engine fails - plan B - have performance to go safely somewhere. Weather worse than expected - plan B - have a safe alternate.

The things to consider have changed (very) slightly, but the philosophy is the same. Of course, there are always the unexpected (eg. unforecast fog rolling in everywhere - it happens - doesn't feel good) or multiple unrelated problems. You can't win every game, all the time, but you can make sure the odds are in your favor.
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