Take-off Alternate Canada

[ATR42DRIVER]

Here is the wx report on the hour:

METAR CYVR 252100Z 08005KT 3/4SM RVR08 3500/N VV100 11/11
A2934 RMK SF1CU2SC3AC2 SLP003=

Do you require a take-off alternate to depart?
Does the RVR supercede the VV100?
I was under the impression that the T/O alt requirement was only for 1200 RVR ops. and 600 RVR ops. Basically if the wx was below minima for landing (200' 1/2sm rvr1200) you would have to find an alternate within 1 hour on 1 engine.
Any clarification would be greatly appreciated.

[JammedStab]

If the ceiling is below the landing limits for the runway with the lowest limits that you can use for landing at your departure airport, then you need a takeoff alternate for airline transport ops. The same goes for visibility but it would be based on the visibility on the approach chart(recommended visibility). So if only an NDB approach is available in YVR with a visibility on the approach chart of 1 1/2 miles(for your category of aircraft), you need a takeoff alternate if YVR's visibility is below that.

So you have to look at the Notams and weather before determining takeoff alternate requirements. It has nothing to do with approach ban type of numbers that you posted. Those are destination requirements.

Remember that it isn't necessarily 1 hour on one engine for all aircraft. Three and four engine aircraft are two hours with 1 engine inoperative. I think it is still based on no wind distance. It went back and forth at my company a few years back. But it can be adjusted for different weights as we have on a couple of different aircraft. Three different ranges for takeoff alternates based on weight.

[ATR42DRIVER]

Thanks for the reply jammedstab. I thought the need for a t/o alternate was if you were unable to return to your departure airport due to wx. With the wx report above I think it wouldn't be too much trouble getting back to YVR. Maybe I'm just missing the point.

[JammedStab]

With the ceiling at minimums and or the visibility at the recommended minimum, you should be able to just legally make it back in. Remember, there is a good chance that you are having some sort of difficulty at the time. Plus if things deteriorate a bit since departure, you can probably still get in.