TAF Question??
When you live....
the plot thickens
Well look at that, amended 7JUN07. Pays to read any changes, doesn't it!
Now this opens a can of worms. Validity periods are going to be out too. A statement of met conditions expected for a specified period in the airspace within 5nm of the centre of the aerodrome runway complex.
So the statement of met conditions for temp and QNH is not valid for 90 minutes prior to the end of a TAF...so to fulfill the requirments of validity of an arrival that a TAF must be valid 60 minutes AFTER arrival then-
Does this mean that arrival now must be 150 minutes prior to the end of validity of the TAF? Certainly doesn't say that in AIP but it stands to reason. The TAF is no longer a valid statement of expected met conditions 90minutes prior to the end of the period. Only a lawyer could come up with this...Not you, creampuff
Now this opens a can of worms. Validity periods are going to be out too. A statement of met conditions expected for a specified period in the airspace within 5nm of the centre of the aerodrome runway complex.
So the statement of met conditions for temp and QNH is not valid for 90 minutes prior to the end of a TAF...so to fulfill the requirments of validity of an arrival that a TAF must be valid 60 minutes AFTER arrival then-
Does this mean that arrival now must be 150 minutes prior to the end of validity of the TAF? Certainly doesn't say that in AIP but it stands to reason. The TAF is no longer a valid statement of expected met conditions 90minutes prior to the end of the period. Only a lawyer could come up with this...Not you, creampuff
I had always treated the 4 forecast values as being equally divided for the forecast period with the first being for the midpoint of the first 25% of the forecast the second for the second 25% etc as this was the only way I could rationalise TAFs of different validity lengths.
Glad I passed my ATPL MET this morning (and before reading this thread)!
UTR
Last edited by UnderneathTheRadar; 10th Jul 2008 at 04:46. Reason: more info
Desmotronic, it would appear no one has picked up on your trick question.
The answer is 300ft ceiling and 2000M vis because of your runway lights being spaced greater than 60M. AIP1.5 4.3.2 So the chances of takeoff at those times and visibility as per the TAF is a/zero and b/zero.
Creampuff-
my thoughts exactly. Good intentions may well have added another unforseen variable to be "interpreted" when before there was none.
The change has given the entry a specific value at a specific time to then be extrapolated 90mins either side of that time. Where before the message was "For 3hrs after this time we expect the T and Q to be this value."
It would also imply that the temperature shown at the start of the TAF is now valid 90 minutes prior to the start of the period of validity of that TAF.
Interesting conversation with my mate ahead of me on this one. A very nice little trap.
The answer is 300ft ceiling and 2000M vis because of your runway lights being spaced greater than 60M. AIP1.5 4.3.2 So the chances of takeoff at those times and visibility as per the TAF is a/zero and b/zero.
Creampuff-
neither method is any more likely than the other to be accurate!
The change has given the entry a specific value at a specific time to then be extrapolated 90mins either side of that time. Where before the message was "For 3hrs after this time we expect the T and Q to be this value."
It would also imply that the temperature shown at the start of the TAF is now valid 90 minutes prior to the start of the period of validity of that TAF.
Interesting conversation with my mate ahead of me on this one. A very nice little trap.
I read it as 800m if >5700kg
800m if <5700kg and 2 pilot or single pilot jet/auto feather prop.
All others unfortunately including me 2000m.
Therefore buckley's and 25%
800m if <5700kg and 2 pilot or single pilot jet/auto feather prop.
All others unfortunately including me 2000m.
Therefore buckley's and 25%
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warning will robinson -there is a little bit more to read before reducing those takeoff minimas
.
- are you intending to return to the departure airport?
- do you read those annoying Note thingies (especially all 5 of them)
.- are you intending to return to the departure airport?
- do you read those annoying Note thingies (especially all 5 of them)
Last edited by Muffinman; 10th Jul 2008 at 06:39. Reason: going back to the 'share-a-tent' sounds excellent
"Why do you care? What are you using the forecast temp for?
The only thing I use them for is to tell the punters what the forecast max is for the day and to work out how quickly I'm going to need to walk from the terminal to the car park at MEL to avoid freezing."
I find this quite arrogant to a genuine question no matter how trivial.
The only thing I use them for is to tell the punters what the forecast max is for the day and to work out how quickly I'm going to need to walk from the terminal to the car park at MEL to avoid freezing."
I find this quite arrogant to a genuine question no matter how trivial.
Nunc est bibendum
Actually Kelly. The question was genuine. The tone implied wasn't a nasty one. More a tone of genuine concern? Why does someone think the forecast temp in 10 hours is important. The answer to that particular question determines the answer. The answer may be get a TTF, get a new TAF, listen to the AWIS, look at your aircraft temperature gauge if you're departing from that aerodrome and concerned about performance, etc.
Perhaps some are looking at my response with their own hang ups foremost in mind. Perhaps if you'd asked for clarification- as I did to the original question- instead of jumping in with your own prejudices and labeling it as arrogant then the response you recieved from me may have been tad more concillatory.
Perhaps some are looking at my response with their own hang ups foremost in mind. Perhaps if you'd asked for clarification- as I did to the original question- instead of jumping in with your own prejudices and labeling it as arrogant then the response you recieved from me may have been tad more concillatory.
