Sunset and nigh flying definitions

In other threads, people are talking of "sunset" as the latest landing
time for flights to IGC Sporting Code rules. I do not think that this
is quite right, I believe that the critical time is a bit later. The
aviation rules of most countries say something like: "Night. The hours
between the end of evening Civil Twilight and the beginning of morning
Civil Twilight. Civil Twilight ends in the evening when the centre of
the sun's disc is 6 degrees below the horizon and begins in the morning
when the centre of the sun's disc is 6 degrees below the horizon".
(Source: Para 53 of FAA Civil Aviation Regulations, Part 1 - General
Policies, Procedures, and Definitions, Version 2.3, October 2002)

The Sporting Code Section 3 Gliding, says: "4.5.3 Night flight. A
flight that continues beyond the hours of legal daylight in the country
concerned shall not be validated, except where the glider and pilot
comply with the laws of that country for night flight."

Are some people taking the first part of this Sporting Code wording to
mean "sunset" rather than Civil Twilight? Perhaps it would be better
if the wording was something like: "A flight that includes any part of
the official night flying period as definined by the Aviation
Authorities in the country concerned, except ... "

The logic of using Civil Twilight is that it is also defined as "the
limit at which illumination is sufficient, under good weather
conditions, for terrestrial objects to be clearly distinguished. At
the beginning of morning Civil Twilight, or end of evening Civil
Twilight, the horizon is clearly defined, only the brightest stars are
normally visible and artificial illumination should not be required to
carry on ordinary outdoor activities".

Finally, there may be insurance considerations as well as sporting and
legal ones. Damage in the event of landing after Civil Twilight may
lead to difficulties with insurers. In the UK, the BGA publishes a
time table of last landing times for this and other reasons, for
application at BGA member clubs.

Ian Strachan
Lasham Gliding Centre, UK

In message . com, Ian
Strachan writes
snip

Civil Twilight ends in the evening when the centre of
the sun's disc is 6 degrees below the horizon and begins in the morning
when the centre of the sun's disc is 6 degrees below the horizon".
Snip

The phrase 'civil twilight' always leaves me wondering what uncivil
twilight is...

(I'll get my coat)

--
Surfer!
Email to: ramwater at uk2 dot net

Ian Strachan wrote:
Are some people taking the first part of this Sporting Code wording to
mean "sunset" rather than Civil Twilight? Perhaps it would be better
if the wording was something like: "A flight that includes any part of
the official night flying period as definined by the Aviation
Authorities in the country concerned, except ... "

Ian, in the USA, the critical issue is that no AIRCRAFT may fly after
SUNSET without proper lighting. If the sailplane has the proper
lighting, then there are no further requirements (if not carrying
passengers) or restrictions about flying between sunset and sunrise.

The "problem" here is that it is quite easy to still be airborne, and
see the ground, etc, well after sunset. But IT IS NOT LEGAL in *most*
sailplanes. Because the FAR most of us are familiar with has to do
with carriage of passengers, many, including myself, have been under
the mistaken impression that it is OK to fly after sunset, but before
twilight.

So, IMO, all that needs to be stated in the SC is that the flight shall
comply with all applicable regulations of the country concerned -
period. In the USA that means that "day" flight is not permitted
during 100% of the FAA defined day, but only between sunrise and sunset
- UNLESS the sailplane is equipped with anti collision lights.

If we want to legislate safety in the SC, then we should just set a
maximum duration of the flight. If there were a full moon, and my
sailplane had the appropriate lighting, I could very safely repeat my
100km speed triangle in wave at midnight. The flight would be less
than 2 hours in duration, and I would at all times be within a 10:1 or
better glide to a good airport. However, if I were in (for example)
Argentina, it could be possible to work the wave for 20, 30, or more
hours. Would that be safe in a single place glider? How about
multiplace? What if Steve Fossett's Global Flyer were converted into a
motorglider, and he decided to attempt a huge wave flight in the Andes?

-Tom

US Federal Aviation Regulation definition of night: From FAR official
definitions
Night means the time between the end of evening civil twilight and the
beginning of morning civil twilight, as published in the American Air
Almanac, converted to local time.

Equipment requirements for night flight: FAR 91.205(c)
(c) Visual flight rules (night). For VFR flight at night, the following
instruments and equipment are required:

(1) Instruments and equipment specified in paragraph (b) of this section.

(2) Approved position lights.

(3) An approved aviation red or aviation white anticollision light system on
all U.S.-registered civil aircraft. Anticollision light systems initially
installed after August 11, 1971, on aircraft for which a type certificate
was issued or applied for before August 11, 1971, must at least meet the
anticollision light standards of part 23, 25, 27, or 29 of this chapter, as
applicable, that were in effect on August 10, 1971, except that the color
may be either aviation red or aviation white. In the event of failure of any
light of the anticollision light system, operations with the aircraft may be
continued to a stop where repairs or replacement can be made.

(4) If the aircraft is operated for hire, one electric landing light.

I can find no reference in the FARs that further limits gliders to
operations between sunrise and sunset.

Ben Jeffrey



"5Z" wrote in message
ups.com...

Ian Strachan wrote:
Are some people taking the first part of this Sporting Code wording to
mean "sunset" rather than Civil Twilight? Perhaps it would be better
if the wording was something like: "A flight that includes any part of
the official night flying period as definined by the Aviation
Authorities in the country concerned, except ... "

Ian, in the USA, the critical issue is that no AIRCRAFT may fly after
SUNSET without proper lighting. If the sailplane has the proper
lighting, then there are no further requirements (if not carrying
passengers) or restrictions about flying between sunset and sunrise.

The "problem" here is that it is quite easy to still be airborne, and
see the ground, etc, well after sunset. But IT IS NOT LEGAL in *most*
sailplanes. Because the FAR most of us are familiar with has to do
with carriage of passengers, many, including myself, have been under
the mistaken impression that it is OK to fly after sunset, but before
twilight.

So, IMO, all that needs to be stated in the SC is that the flight shall
comply with all applicable regulations of the country concerned -
period. In the USA that means that "day" flight is not permitted
during 100% of the FAA defined day, but only between sunrise and sunset
- UNLESS the sailplane is equipped with anti collision lights.

If we want to legislate safety in the SC, then we should just set a
maximum duration of the flight. If there were a full moon, and my
sailplane had the appropriate lighting, I could very safely repeat my
100km speed triangle in wave at midnight. The flight would be less
than 2 hours in duration, and I would at all times be within a 10:1 or
better glide to a good airport. However, if I were in (for example)
Argentina, it could be possible to work the wave for 20, 30, or more
hours. Would that be safe in a single place glider? How about
multiplace? What if Steve Fossett's Global Flyer were converted into a
motorglider, and he decided to attempt a huge wave flight in the Andes?

-Tom

Ben Jeffrey wrote:
US Federal Aviation Regulation definition of night: From FAR official
definitions
Night means the time between the end of evening civil twilight and the
beginning of morning civil twilight, as published in the American Air
Almanac, converted to local time.

Equipment requirements for night flight: FAR 91.205(c)
(c) Visual flight rules (night). For VFR flight at night, the following
instruments and equipment are required:

(1) Instruments and equipment specified in paragraph (b) of this section.

(2) Approved position lights.

(3) An approved aviation red or aviation white anticollision light system on
all U.S.-registered civil aircraft. Anticollision light systems initially
installed after August 11, 1971, on aircraft for which a type certificate
was issued or applied for before August 11, 1971, must at least meet the
anticollision light standards of part 23, 25, 27, or 29 of this chapter, as
applicable, that were in effect on August 10, 1971, except that the color
may be either aviation red or aviation white. In the event of failure of any
light of the anticollision light system, operations with the aircraft may be
continued to a stop where repairs or replacement can be made.

(4) If the aircraft is operated for hire, one electric landing light.

I can find no reference in the FARs that further limits gliders to
operations between sunrise and sunset.

See 91.209.


Ben Jeffrey

I guess that answers it in black and white. I searched for glider
specific.

Ben Jeffrey


T o d d P a t t i s t wrote:
"Ben Jeffrey" wrote:

Equipment requirements for night flight: FAR 91.205(c)

I can find no reference in the FARs that further limits gliders to
operations between sunrise and sunset.

It's there, you just need to go a little further down the
FARs to this one:

Sec. 91.209 Aircraft lights.
No person may:
(a) During the period from sunset to sunrise ....
(1) Operate an aircraft unless it has lighted position
lights; ..

Gliders are "aircraft" and most don't have "lighted position
lights" so most gliders can't fly from "sunset to sunrise."
You will hunt in vain in the FARs for a definition of sunset
or sunrise, but we can assume the FAA will come up with one
if they want to charge you :-)

--
T o d d P a t t i s t - "WH" Ventus C
(Remove DONTSPAMME from address to email reply.)

But, as I have recently told you all ad nauseam, sunset is NOT defined
in the FARs, nor is it known with an accuracy of better than a few
minutes.

Complaining of a flight that lands a few minutes after sunset is, in my
view, picayune to the extreme. Analagous to trapping motorists who
exceed a speed limit by less than 1%. I'm sure no-one at the FAA
would ever worry about this unless it was a contributory factor to an
accident. I certainly know of no enforcement action by any authority in
such cases.

However, I'll never be as good as you guys, I'm afraid. I freely admit
to driving over the speed limit every day, rolling through stop signs
and breaking sundry other driving regulations from time to time. I
also sometimes fly closer to clouds than I should, have flown through
airspace that maybe I shouldn't and have landed after sunset on a
couple of occasions.

Mike



Greg Arnold wrote:
Ben Jeffrey wrote:
US Federal Aviation Regulation definition of night: From FAR official
definitions
Night means the time between the end of evening civil twilight and the
beginning of morning civil twilight, as published in the American Air
Almanac, converted to local time.

Equipment requirements for night flight: FAR 91.205(c)
(c) Visual flight rules (night). For VFR flight at night, the following
instruments and equipment are required:

(1) Instruments and equipment specified in paragraph (b) of this section.

(2) Approved position lights.

(3) An approved aviation red or aviation white anticollision light system on
all U.S.-registered civil aircraft. Anticollision light systems initially
installed after August 11, 1971, on aircraft for which a type certificate
was issued or applied for before August 11, 1971, must at least meet the
anticollision light standards of part 23, 25, 27, or 29 of this chapter, as
applicable, that were in effect on August 10, 1971, except that the color
may be either aviation red or aviation white. In the event of failure of any
light of the anticollision light system, operations with the aircraft may be
continued to a stop where repairs or replacement can be made.

(4) If the aircraft is operated for hire, one electric landing light.

I can find no reference in the FARs that further limits gliders to
operations between sunrise and sunset.

See 91.209.


Ben Jeffrey

But, as I have recently told you all ad nauseam, sunset is NOT defined
in the FARs, nor is it known with an accuracy of better than a few
minutes.

Complaining of a flight that lands a few minutes after sunset is, in my
view, picayune to the extreme. Analagous to trapping motorists who
exceed a speed limit by less than 1%. I'm sure no-one at the FAA would
ever worry about this unless it was a contributory factor to an
accident. I certainly know of no enforcement action by any authority in
such cases.

However, I'll never be as good as you guys, I'm afraid. I freely admit
to driving over the speed limit every day, rolling through stop signs
and breaking sundry other drivng regulations. I also sometimes fly
closer to clouds than I should, have flown through airspace that maybe
I shouldn't and have landed after sunset on a couple of occasions.

Mike



Greg Arnold wrote:
Ben Jeffrey wrote:
US Federal Aviation Regulation definition of night: From FAR official
definitions
Night means the time between the end of evening civil twilight and the
beginning of morning civil twilight, as published in the American Air
Almanac, converted to local time.

Equipment requirements for night flight: FAR 91.205(c)
(c) Visual flight rules (night). For VFR flight at night, the following
instruments and equipment are required:

(1) Instruments and equipment specified in paragraph (b) of this section.

(2) Approved position lights.

(3) An approved aviation red or aviation white anticollision light system on
all U.S.-registered civil aircraft. Anticollision light systems initially
installed after August 11, 1971, on aircraft for which a type certificate
was issued or applied for before August 11, 1971, must at least meet the
anticollision light standards of part 23, 25, 27, or 29 of this chapter, as
applicable, that were in effect on August 10, 1971, except that the color
may be either aviation red or aviation white. In the event of failure of any
light of the anticollision light system, operations with the aircraft may be
continued to a stop where repairs or replacement can be made.

(4) If the aircraft is operated for hire, one electric landing light.

I can find no reference in the FARs that further limits gliders to
operations between sunrise and sunset.

See 91.209.


Ben Jeffrey

Ben Jeffrey wrote:
US Federal Aviation Regulation definition of night: From FAR official
definitions
Night means the time between the end of evening civil twilight and the
beginning of morning civil twilight, as published in the American Air
Almanac, converted to local time.

Equipment requirements for night flight: FAR 91.205(c)
(c) Visual flight rules (night). For VFR flight at night, the following
instruments and equipment are required:

(1) Instruments and equipment specified in paragraph (b) of this section.

(2) Approved position lights.

(3) An approved aviation red or aviation white anticollision light system on
all U.S.-registered civil aircraft. Anticollision light systems initially
installed after August 11, 1971, on aircraft for which a type certificate
was issued or applied for before August 11, 1971, must at least meet the
anticollision light standards of part 23, 25, 27, or 29 of this chapter, as
applicable, that were in effect on August 10, 1971, except that the color
may be either aviation red or aviation white. In the event of failure of any
light of the anticollision light system, operations with the aircraft may be
continued to a stop where repairs or replacement can be made.

(4) If the aircraft is operated for hire, one electric landing light.

I can find no reference in the FARs that further limits gliders to
operations between sunrise and sunset.

Technically, this is not a requirement for gliders. See the full
heading:

91.205: Powered civil aircraft with standard category U.S.
airworthiness certificates: Instrument and equipment requirements.

Note that this is for *powered* aircraft, so would apply to
motorgliders, but not pure gliders. However, if the glider has a
standard airworthiness certificate, it is probably limited to VFR day
only. If it is experimental, it probably has the same restriction; if
not, there would be specific requirements for night flying equipment
which would probably also include cockpit lighting in addition to
position and possibly anti-collision lights.

Ben,

Are you saying that all this discussion has been about NOTHING??

It was asserted the FARs had a requirement for nav and anti-collision
lights after sunset and the SSA-OLC Committee assumes that no gliders
have such lights so flights ending after sunset are deemed invalid.

I saw no sign that the argument was about flying after civil twilight -
ie, in the dark. So it wasn't about safety but about the technicality
of displaying lights between sunset and darkness.

Or did some posters not understand night doesn't begin at sunset?

Are you saying there's no such rule???

GC

Ben Jeffrey wrote:
US Federal Aviation Regulation definition of night: From FAR official
definitions
Night means the time between the end of evening civil twilight and the
beginning of morning civil twilight, as published in the American Air
Almanac, converted to local time.

Equipment requirements for night flight: FAR 91.205(c)
(c) Visual flight rules (night). For VFR flight at night, the following
instruments and equipment are required:

(1) Instruments and equipment specified in paragraph (b) of this section.

(2) Approved position lights.

(3) An approved aviation red or aviation white anticollision light system on
all U.S.-registered civil aircraft. Anticollision light systems initially
installed after August 11, 1971, on aircraft for which a type certificate
was issued or applied for before August 11, 1971, must at least meet the
anticollision light standards of part 23, 25, 27, or 29 of this chapter, as
applicable, that were in effect on August 10, 1971, except that the color
may be either aviation red or aviation white. In the event of failure of any
light of the anticollision light system, operations with the aircraft may be
continued to a stop where repairs or replacement can be made.

(4) If the aircraft is operated for hire, one electric landing light.

I can find no reference in the FARs that further limits gliders to
operations between sunrise and sunset.

Ben Jeffrey



"5Z" wrote in message
ups.com...
Ian Strachan wrote:
Are some people taking the first part of this Sporting Code wording to
mean "sunset" rather than Civil Twilight? Perhaps it would be better
if the wording was something like: "A flight that includes any part of
the official night flying period as definined by the Aviation
Authorities in the country concerned, except ... "
Ian, in the USA, the critical issue is that no AIRCRAFT may fly after
SUNSET without proper lighting. If the sailplane has the proper
lighting, then there are no further requirements (if not carrying
passengers) or restrictions about flying between sunset and sunrise.

The "problem" here is that it is quite easy to still be airborne, and
see the ground, etc, well after sunset. But IT IS NOT LEGAL in *most*
sailplanes. Because the FAR most of us are familiar with has to do
with carriage of passengers, many, including myself, have been under
the mistaken impression that it is OK to fly after sunset, but before
twilight.

So, IMO, all that needs to be stated in the SC is that the flight shall
comply with all applicable regulations of the country concerned -
period. In the USA that means that "day" flight is not permitted
during 100% of the FAA defined day, but only between sunrise and sunset
- UNLESS the sailplane is equipped with anti collision lights.

If we want to legislate safety in the SC, then we should just set a
maximum duration of the flight. If there were a full moon, and my
sailplane had the appropriate lighting, I could very safely repeat my
100km speed triangle in wave at midnight. The flight would be less
than 2 hours in duration, and I would at all times be within a 10:1 or
better glide to a good airport. However, if I were in (for example)
Argentina, it could be possible to work the wave for 20, 30, or more
hours. Would that be safe in a single place glider? How about
multiplace? What if Steve Fossett's Global Flyer were converted into a
motorglider, and he decided to attempt a huge wave flight in the Andes?

-Tom