I admit this is a tricky question. First you have to determine all the possible alternate minimums you can have. In Canada, we can use the alternate minima + the sliding scale.
Step 1: The alternate minima given is 600-2. The associated sliding scale is 700 - 1 1/2 and 800 - 1. This is only a Canadian thing. Other parts of the world don't use sliding scales, just alternate minima only. So, we have 3 answers to choose. (600-2; 700- 1 1/2; 800-1).
Step 2: Now add all the flight times: CYYC-CYQR-CYXE = 3 hours.
Step 3: Review the TAF:
TAF CYXE 281139Z 2812/2912 24010G25KT 27050KT 5SM –SN BKN004 OVC010 TEMPO 2818/2901 1 1/2SM –SN BLSN BKN010 PROB30 2820/2822 1/2SM SN VV005 FM290200Z 28010KT 1SM –SN BKN007 BECMG 2906/2908 000000KT 1SM BKN008 RMK NXT FCST BY 281800Z
The only legal portion of the TAF is 800-1 from our sliding scale above.
Step 4: Review the CAP Gen
Aerodrome forecasts (TAF) that contain the terms BECMG, TEMPO or PROB may be used to determine the weather suitability of an aerodrome as an alternate, provided that:
- where conditions are forecast to improve, the forecast BECMG condition shall be considered to be applicable as of the end of the BECMG time period, and these conditions shall not be below the published alternate minima requirements for that aerodrome;
- where conditions are forecast to deteriorate, the forecast BECMG condition shall be considered to be applicable as of the start of the BECMG time period, and these conditions shall not be below the published alternate minima requirements for that aerodrome;
- the forecast TEMPO condition shall not be below the published alternate minima requirements for that aerodrome; and
- the forecast PROB condition shall not be below the appropriate landing minima for that aerodrome.
The weather is forecast to begin at 06Z and end of 08Z. Since the ceiling are improving we must use the END OF THE FORECASTED PERIOD.
0800Z - 3 hours flight time = 0500Z
I admit this is a tricky question. First you have to determine all the possible alternate minimums you can have. In Canada, we can use the alternate minima + the sliding scale.
Step 1: The alternate minima given is 600-2. The associated sliding scale is 700 - 1 1/2 and 800 - 1. This is only a Canadian thing. Other parts of the world don't use sliding scales, just alternate minima only. So, we have 3 answers to choose. (600-2; 700- 1 1/2; 800-1).
Step 2: Now add all the flight times: CYYC-CYQR-CYXE = 3 hours.
Step 3: Review the TAF:
TAF CYXE 281139Z 2812/2912 24010G25KT 27050KT 5SM –SN BKN004 OVC010 TEMPO 2818/2901 1 1/2SM –SN BLSN BKN010 PROB30 2820/2822 1/2SM SN VV005 FM290200Z 28010KT 1SM –SN BKN007 BECMG 2906/2908 000000KT 1SM BKN008 RMK NXT FCST BY 281800Z
The only legal portion of the TAF is 800-1 from our sliding scale above.
Step 4: Review the CAP Gen
Aerodrome forecasts (TAF) that contain the terms BECMG, TEMPO or PROB may be used to determine the weather suitability of an aerodrome as an alternate, provided that:
- where conditions are forecast to improve, the forecast BECMG condition shall be considered to be applicable as of the end of the BECMG time period, and these conditions shall not be below the published alternate minima requirements for that aerodrome;
- where conditions are forecast to deteriorate, the forecast BECMG condition shall be considered to be applicable as of the start of the BECMG time period, and these conditions shall not be below the published alternate minima requirements for that aerodrome;
- the forecast TEMPO condition shall not be below the published alternate minima requirements for that aerodrome; and
- the forecast PROB condition shall not be below the appropriate landing minima for that aerodrome.
The weather is forecast to begin at 06Z and end of 08Z. Since the ceiling are improving we must use the END OF THE FORECASTED PERIOD.
0800Z - 3 hours flight time = 0500Z