Rogue IFR

"Steven P. McNicoll" wrote in message
ink.net...

"G.R. Patterson III" wrote in message
...

It wouldn't matter. The pilot under discussion here doesn't have an
instrument rating, so he can't get an SVFR clearance anyway.


That restriction applies only between sunset and sunrise.

More like between 30 minutes after sunset and 30 minutes before sunrise,
roughly, the rule of thumb for night ops in the continental US, not to be
confused with the one hour after sundown rule for logging night flight time.

The ICAO definition is when the center the sun is 6 degrees or more below
the horizon which is about 24 minutes after dusk/before dawn at the equator,
sometimes much longer than that above the arctic circle or below the
antarctic circle

In article . net,
Greg Goodknight wrote:
instrument rating, so he can't get an SVFR clearance anyway.

That restriction applies only between sunset and sunrise.

More like between 30 minutes after sunset and 30 minutes before sunrise,
roughly, the rule of thumb for night ops in the continental US, not to be
confused with the one hour after sundown rule for logging night flight time.

Err, 'night' in the FAR is defined in 14 CFR Part 1 and it's based on
civil twilight.

The SVFR regulations in 91.157(b)(4) says sunset-sunrise, not "night",
so the other poster was exactly right.

It's 61.57(b) (night currency) that uses the "hour after sunset".

The ICAO definition is when the center the sun is 6 degrees or more below
the horizon

Which is the definition of the end of civil twilight.

--
Ben Jackson

http://www.ben.com/

"Ben Jackson" wrote in message
news:RYfnb.44209$HS4.185004@attbi_s01...
In article . net,
Greg Goodknight wrote:
instrument rating, so he can't get an SVFR clearance anyway.

That restriction applies only between sunset and sunrise.

More like between 30 minutes after sunset and 30 minutes before sunrise,
roughly, the rule of thumb for night ops in the continental US, not to be
confused with the one hour after sundown rule for logging night flight
time.

Err, 'night' in the FAR is defined in 14 CFR Part 1 and it's based on
civil twilight.

The SVFR regulations in 91.157(b)(4) says sunset-sunrise, not "night",
so the other poster was exactly right.

It's 61.57(b) (night currency) that uses the "hour after sunset".

The ICAO definition is when the center the sun is 6 degrees or more below
the horizon

Which is the definition of the end of civil twilight.

6 degrees, at the equator, is 24 minutes, do the math (remember, 360 degrees
in 24 hours) but that's at the equator. When Grass Valley (O17) had a night
closure a few years ago over a trees and obstruction light snafu, I pressed
the issue with the local FSDO; they came back with 30 minutes being the rule
of thumb they use in the 48 states.

-Greg



--
Ben Jackson

http://www.ben.com/

"Greg Goodknight" wrote in message
hlink.net...

6 degrees, at the equator, is 24 minutes, do the math (remember, 360
degrees in 24 hours) but that's at the equator.


No math required, read the regulation.



When Grass Valley (O17) had a night
closure a few years ago over a trees and obstruction light snafu,


SVFR is not available at O17.



I pressed the issue with the local FSDO; they came back with
30 minutes being the rule of thumb they use in the 48 states.



The US has fifty states.

It's not a "rule of thumb", it's a regulation. The regulation clearly
states that fixed-wing Special VFR operations may only be conducted between
sunrise and sunset (or in Alaska, when the sun is 6 degrees or more below
the horizon) unless the pilot and airplane are capable of IFR flight.

"Steven P. McNicoll" wrote in message
hlink.net...

"Greg Goodknight" wrote in message
hlink.net...

6 degrees, at the equator, is 24 minutes, do the math (remember, 360
degrees in 24 hours) but that's at the equator.


No math required, read the regulation.

I did. What is the working definition of "sunrise" and "sunset" here?




When Grass Valley (O17) had a night
closure a few years ago over a trees and obstruction light snafu,


SVFR is not available at O17.

I didn't say it was. I *was* relating how the local FSDO popped up with 30
minutes for a local regulatory issue.




I pressed the issue with the local FSDO; they came back with
30 minutes being the rule of thumb they use in the 48 states.



The US has fifty states.

Ya don't say! Brilliant observation, Sherlock. Trying to be snotty, are we?
The US has 50 plus some occupied territory (including D.C.) but I was
talking about 48 of them. You can guess which ones if you try. I probably
could have said 49 but I wasn't sure if Hawaii was included in the factoid.


It's not a "rule of thumb", it's a regulation. The regulation clearly
states that fixed-wing Special VFR operations may only be conducted
between
sunrise and sunset (or in Alaska, when the sun is 6 degrees or more below
the horizon) unless the pilot and airplane are capable of IFR flight.

Yes, Alaska sometimes doesn't have a sunrise or sunset.

The ICAO has the 6 degree rule to define twilight; not the sun 6 degrees
below the horizon, but the midpoint of the sun being 6 degrees below the
horizon. For some of that time the sun is showing, and around here there is
light good enough for unlit airport operations until about 30 minutes after
the sun's midpoint is on the ideal horizon, or 30 minutes before for
"sunup". Since that reg calls it sunrise and sunset for 49 states but in
essence quotes the ICAO definition for twilight for Alaska, I'm going to
believe they were not defining a lower standard for Alaska but rather
letting Alaska's aviators figure it out for themselves when they don't have
most would call a daily sunrise and sunset, and when you can see sunlight in
the morning (which is six degrees) it's sunrise, and in the evening and you
can't see sunlight that's sunset.

If controllers really do stop day SVFR operations in California when it's
still light enough to see, I stand corrected; and it could be a lower light
standard in Alaska because the light levels change slowly there. You may
have caught me this time, Steven. It's about time you got one right!

-Greg

"Greg Goodknight" wrote in message
ink.net...

More like between 30 minutes after sunset and 30 minutes before sunrise,
roughly, the rule of thumb for night ops in the continental US, not to be
confused with the one hour after sundown rule for logging night flight
time.


No, it's between sunset and sunrise, except for Alaska.


§91.157 Special VFR weather minimums.

(a) Except as provided in appendix D, section 3, of this part, special VFR
operations may be conducted under the weather minimums and requirements of
this section, instead of those contained in §91.155, below 10,000 feet MSL
within the airspace contained by the upward extension of the lateral
boundaries of the controlled airspace designated to the surface for an
airport.

(b) Special VFR operations may only be conducted --

(1) With an ATC clearance;

(2) Clear of clouds;

(3) Except for helicopters, when flight visibility is at least 1 statute
mile; and

(4) Except for helicopters, between sunrise and sunset (or in Alaska, when
the sun is 6 degrees or more below the horizon) unless --

(i) The person being granted the ATC clearance meets the applicable
requirements for instrument flight under part 61 of this chapter; and

(ii) The aircraft is equipped as required in §91.205(d).

(c) No person may take off or land an aircraft (other than a helicopter)
under special VFR --

(1) Unless ground visibility is at least 1 statute mile; or

(2) If ground visibility is not reported, unless flight visibility is at
least 1 statute mile. For the purposes of this paragraph, the term flight
visibility includes the visibility from the cockpit of an aircraft in
takeoff position if:

(i) The flight is conducted under this part 91; and

(ii) The airport at which the aircraft is located is a satellite airport
that does not have weather reporting capabilities.

(d) The determination of visibility by a pilot in accordance with paragraph
(c)(2) of this section is not an official weather report or an official
ground visibility report.

[Amdt. 91-235, 58 FR 51968, Oct. 5, 1993, as amended by Amdt. 91-247, 60 FR
66874, Dec. 27, 1995; Amdt. 91-262, 65 FR 16116, Mar. 24, 2000]

"Steven P. McNicoll" wrote in message
k.net...

"Greg Goodknight" wrote in message
ink.net...

More like between 30 minutes after sunset and 30 minutes before sunrise,
roughly, the rule of thumb for night ops in the continental US, not to
be
confused with the one hour after sundown rule for logging night flight
time.


No, it's between sunset and sunrise, except for Alaska.

(4) Except for helicopters, between sunrise and sunset (or in Alaska, when
the sun is 6 degrees or more below the horizon)

The 30 minutes after the sun is half obscured is the estimate for six
degrees in the continental US outside of Alaska. I believe that's the
working definition for sunrise and sunset mentioned here for Alaska and is
the ICAO definition repeated in the FAR or AIM (I forget which)

At the equator, with the Earth rotating 360 degrees in 24*60minutes, 6
degrees is 24 minutes.

It really is the time when there is no longer enough natural light to land
at an unlit airport, in good weather.

-Greg



§91.157 Special VFR weather minimums.

(a) Except as provided in appendix D, section 3, of this part, special VFR
operations may be conducted under the weather minimums and requirements of
this section, instead of those contained in §91.155, below 10,000 feet MSL
within the airspace contained by the upward extension of the lateral
boundaries of the controlled airspace designated to the surface for an
airport.

(b) Special VFR operations may only be conducted --

(1) With an ATC clearance;

(2) Clear of clouds;

(3) Except for helicopters, when flight visibility is at least 1 statute
mile; and

(4) Except for helicopters, between sunrise and sunset (or in Alaska,
when
the sun is 6 degrees or more below the horizon) unless --

(i) The person being granted the ATC clearance meets the applicable
requirements for instrument flight under part 61 of this chapter; and

(ii) The aircraft is equipped as required in §91.205(d).

(c) No person may take off or land an aircraft (other than a helicopter)
under special VFR --

(1) Unless ground visibility is at least 1 statute mile; or

(2) If ground visibility is not reported, unless flight visibility is at
least 1 statute mile. For the purposes of this paragraph, the term flight
visibility includes the visibility from the cockpit of an aircraft in
takeoff position if:

(i) The flight is conducted under this part 91; and

(ii) The airport at which the aircraft is located is a satellite
airport
that does not have weather reporting capabilities.

(d) The determination of visibility by a pilot in accordance with
paragraph
(c)(2) of this section is not an official weather report or an official
ground visibility report.

[Amdt. 91-235, 58 FR 51968, Oct. 5, 1993, as amended by Amdt. 91-247, 60
FR
66874, Dec. 27, 1995; Amdt. 91-262, 65 FR 16116, Mar. 24, 2000]

"Greg Goodknight" wrote in message
news

It really is the time when there is no longer enough natural light to land
at an unlit airport, in good weather.


No, it really is sunset and sunrise. I posted the regulation, I suggest you
read it.