Could someone please explain this question and answer on the practice IREX exams as I am confused about the time.
As a TEMPO is allowing 60 minutes of changed weather - I would have thought the answer was
30 minutes before to 60 minutes after the forecast TEMPO period

When a TAF includes a TEMPO period during which conditions will deteriorate to below the alternate minima for that aerodrome, the OPR imposed will apply for all IFR aircraft with an ETA that falls within a time period from -


Select one:


60 minutes before to 30 minutes after the forecast TEMPO period

30 minutes before to 30 minutes after the forecast TEMPO period

30 minutes before to 60 minutes after the forecast TEMPO period

60 minutes before to 60 minutes after the forecast TEMPO period


Answer

The operational requirement [OPR] applies 30 minutes before and 30 minutes after the stated times of commencement and ending of the TEMPO period.

AIP ENR 1.1 para 58.2.1 and AIP ENR 1.1 para 58.2.4


The correct answer is: 30 minutes before to 30 minutes after the forecast TEMPO period

Appreciate help

Hey mate,

Look at this taf:

TAF YCOM 241915Z 2420/2508 16015KT 9999 BKN 020 SCT 040
TEMPO 02/05 3000 THUNDERSTORMS WITH RAIN BKN 010
FEW040CB
T 15 21 23 19 Q 1010 1012 1010 1008

Here you can see that the tempo begins at 02 and ends at 05. If you were planning a flight to YCOM and your ETA fell between 0130 and 0530 (30 minutes before and after) then you would be required to have an alternate or 60 minutes holding fuel. But also remember that if your ETA falls within the last half hour (Example: 0515) then you would only need to have enough holding fuel to get you to the end of that half hour, and not a full 60 minutes (in the case of the example, you would only need 15 minutes holding fuel to get you to 0530).

Hope this helps.

G'day,

Let's look at an example:

TEMPO 0602/0608 <SOME BAD WEATHER>

What the Met officer is saying here is "I reckon there will be periods of crappy weather and each period will last up to an hour (30-59 minutes) but I reckon the first one won't start before 0200 on the 6th and I reckon the last period will finish by 0800 on the 6th"

We have an OPR 0130 until 0830 to cover the following:
What if the first period of bad weather actually turns up 30 minutes earlier than expected???
What if the last period actually overruns by 30 minutes???

So, we apply the safety buffers 30 minutes either side, but 30 minutes after the TEMPO period, the OPR expires - i.e. we no longer have an OPR. So, even though it is a TEMPO period, we will never need to carry holding fuel beyond 0830.

For example:
If we plan to arrive at 0130, and decide to hold, we would have to carry 60 minute holding because it is a TEMPO period and we are inside the 30 minutes safety buffer.
If we plan to arrive at 0430, and decide to hold, we would have to carry 60 minute holding because it is a TEMPO period and we are well inside the TEMPO period.
If we plan to arrive at 0530, and decide to hold, we would have to carry 60 minute holding because it is a TEMPO period and we need to hold until the OPR expires at 0630.
If we plan to arrive at 0800, and decide to hold, we only need to carry enough fuel to hold unitl 0830 - i.e. 30 minute holding fuel.
If we plan to arrive at 0820, and decide to hold, we only need to carry enough fuel to hold until 0830 - i.e. 15minutes holding fuel.

Cheers,

Rich

Rich can you explain why the OPR ends at 0630 when the Tempo in this example ends at 0800. I would have thought the OPR would end at 0830

Hi Anton,

The TEMPO does indeed finish at 0830. I had a brainfart and have now corrected my post. Thanks for pointing that out and sorry for any confusion!

Cheers,

Rich

Thanks all
I am getting a much better understanding of TAF's now
Cheers
Rob