• Takeoff Minima vs Runway Level of Service

Posted: **Wed Jul 24, 2019 8:53 am**

Okay, I don't know why this is just now confusing me. Maybe I'm having a brain dead day. Anyway....

Why the heck do they specify 1/2sm visibility for take off minima (in departure procedure) even for runways that are certified down to 1200RVR or 1/4sm? Is this not confusing anyone else?

Take for example Thunder Bay. The Departure Procedure for runway 07 requires 1/2 mile. So to take off and have sufficient obstacle and terrain clearance we need 1/2sm, right? But no, because runway 07 level of service is down to RVR1200, which means if RVR is 1200 or more we can taxi AND takeoff runway 07 with only 1200RVR. Am I missing something?

Posted: **Wed Jul 24, 2019 10:44 am**

The only reference I see to 1/2 mile is for “all other aircraft”, as in if you don’t have the special authorization for reduced visibility operations (ops spec).

So runway 07 is an RVOP runway when it meets the requirements “HIRL or RCLM” and May be used down to 1200 RVR or 1/4 sm if you have the SA to operate in RVOP.

Posted: **Wed Jul 24, 2019 12:04 pm**

That 1/2 mile you see applies to anyone and everyone. A lot of operators are approved down to 1/4 mile with conditions regardless of the published requirements. However, the runway in question HAS to have a level of service that supports it.

Posted: **Thu Jul 25, 2019 5:56 am**

askingquestions24 wrote: ↑Wed Jul 24, 2019 8:53 am Okay, I don't know why this is just now confusing me. Maybe I'm having a brain dead day. Anyway....

Why the heck do they specify 1/2sm visibility for take off minima (in departure procedure) even for runways that are certified down to 1200RVR or 1/4sm? Is this not confusing anyone else?

Take for example Thunder Bay. The Departure Procedure for runway 07 requires 1/2 mile. So to take off and have sufficient obstacle and terrain clearance we need 1/2sm, right? But no, because runway 07 level of service is down to RVR1200, which means if RVR is 1200 or more we can taxi AND takeoff runway 07 with only 1200RVR. Am I missing something?

The obstacle clearance is just generic, most larger operators have aircraft specific obstacle clearance assessments that allow them to not be required to adhere to it due to increased climb rates or modified procedures in the event of an engine failure.

Takeoff Minima vs Runway Level of Service

Takeoff Minima vs Runway Level of Service

Re: Takeoff Minima vs Runway Level of Service

Re: Takeoff Minima vs Runway Level of Service

Re: Takeoff Minima vs Runway Level of Service