VFR transition question

[Ryan B]

CRQ is IFR because of some marine layer directly over the field. I want to depart OKB and transition VFR through the class D southbound. I can maintain vfr where I'm flying, but the ATIS is saying field is IFR. Can I transition under VFR even though the field is IFR?

Discussion...

I've always thought no - AIM 4-4-6 says

"An ATC clearance must be obtained prior to
operating within a Class B, Class C, Class D, or
Class E surface area when the weather is less than that
required for VFR flight"

I should also ask about transitioning the class E surface area to the NW (this discussion came up at my facility - no solid answer either way imo)... but let's start with the class D question!

[Kyle.Sanders]

Well, the source of the field ATIS is going to be from an earlier time than the current observation by the pilot. It would seem to me that if the pilot is able to maintain basic VFR conditions, there should be no problem with ATC approving that transition. If anything, the pilot could always request SVFR (I assume the SVFR minimums can be met as you said that you could possibly maintain VFR from where you were at).

[Ryan B]

I know of SVFR, but I'm wondering if I can go under VFR? As for the time, the ATIS is the current weather until a SPECI comes out, or the tower calls the visibility and it is lower than the ASOS/AWOS.

[Kyle.Sanders]

This is a very interesting question. I was just brainstorming a bit. I am looking forward to seeing the legal battle unfold in this thread.

[Peter Grey]

This one is surprising straight forward:

All from 91.155:

(c) Except as provided in §91.157, no person may operate an aircraft beneath the ceiling under VFR within the lateral boundaries of controlled airspace designated to the surface for an airport when the ceiling is less than 1,000 feet.

And

(d) Except as provided in §91.157 of this part, no person may take off or land an aircraft, or enter the traffic pattern of an airport, under VFR, within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for an airport—

(1) Unless ground visibility at that airport is at least 3 statute miles; or

(2) If ground visibility is not reported at that airport, unless flight visibility during landing or takeoff, or while operating in the traffic pattern is at least 3 statute miles.

91.157 is SVFR.

So you can't transition if the ceiling is under 1000' but you can transition if the reported visibility is under 3 miles (you still have to have 3 mile vis however).

This answers the Class D and E question.

[RyanK]

This one is surprising straight forward:

All from 91.155:

(c) Except as provided in §91.157, no person may operate an aircraft beneath the ceiling under VFR within the lateral boundaries of controlled airspace designated to the surface for an airport when the ceiling is less than 1,000 feet.

Seems to me this wouldn't preclude a transition above the ceiling, like in the case of a thin marine layer over the airport.

[Ryan B]

Where are you getting the 1000 ft ceilings from?

I see 91.155 and it says can't operate VFR with wx minimums less than (required for class D) ... and it states only "flight visibility" and "distance from clouds." 500 ft below for class D basic VFR weather minimums.

text added for accuracy: (a) Except as provided in paragraph (b) of this section and §91.157, no person may operate an aircraft under VFR when the flight visibility is less, or at a distance from clouds that is less, than that prescribed for the corresponding altitude and class of airspace in the following table...

Class D 3 statute miles 500 feet below.
1,000 feet above.
2,000 feet horizontal.

EDIT: Oh wait I see it beneath it reference the 1000 ft ceiling. What is the point of writing the first part of 91.155 without the word "ceiling," then using the word "ceiling" later in part c? I don't understand why the lawyers would provide that nice table for Wx minimums then dash your hopes and include the ceilings in part C below.

[Peter Grey]

Seems to me this wouldn't preclude a transition above the ceiling, like in the case of a thin marine layer over the airport.

I agree with this, you can fly above a ceiling with no restrictions.

EDIT: Oh wait I see it beneath it reference the 1000 ft ceiling. What is the point of writing the first part of 91.155 without the word "ceiling," then using the word "ceiling" later in part c? I don't understand why the lawyers would provide that nice table for Wx minimums then dash your hopes and include the ceilings in part C below.

Because you need the table to dictate actions around clouds that don't constitute a ceiling. You can still be legally below a scattered layer and the table tells you how far below you have to be, but yes as written it's a bit confusing.