Night flying times

There is confusion in regard to which "twilight" times are used to
define night flying. What would be wrong with a change to the FARs that
say something like "Flight occuring an hour after GPS-indicated sunset
time and an hour before GPS-indicated sunrise is defined as night
flying"? (The standard exception for Alaska must be included...)

What's wrong with saying "as published in the American Air Almanac"?

Andrew Sarangan wrote:
What's wrong with saying "as published in the American Air Almanac"?


I seem to have misplaced my copy.

On 8 Nov 2005 05:50:19 -0800, "Andrew Sarangan"
wrote:

What's wrong with saying "as published in the American Air Almanac"?

1. The American Air Almanac is out of print. It is not available on
amazon.com although it may be available elsewhere. However, it has
certainly not been updated in recent years.

2. If the purpose of night flying regulations is to require the currency
of special skills when it is "dark", then the times should be adjusted to
reflect local topography. For example, ridges and mountains may cause
darkness to be present earlier than the official sunset time.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

2. If the purpose of night flying regulations is to require the currency
of special skills when it is "dark", then the times should be adjusted to
reflect local topography. For example, ridges and mountains may cause
darkness to be present earlier than the official sunset time.

I think this is one of those places where judgement comes into play.
We're not talking about much of a temporal difference.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

On Tue, 08 Nov 2005 17:13:07 GMT, Jose wrote:

2. If the purpose of night flying regulations is to require the currency
of special skills when it is "dark", then the times should be adjusted to
reflect local topography. For example, ridges and mountains may cause
darkness to be present earlier than the official sunset time.

I think this is one of those places where judgement comes into play.
We're not talking about much of a temporal difference.

Jose

Well, there are legal, practical and safety issues also. On 29 March 2001
there was a fatal accident involving a Gulfstream at Aspen. They were
executing an approach that was not authorized "at night". "Official"
sunset occurred 33 minutes prior to the accident, so "official" night would
have occurred 3 minutes prior to the accident.

However, according to the NTSB calculations, the sun would have set below
the mountainous terrain about 25 minutes BEFORE official sunset time; and
the shadow for the ridge immediately to the west of the accident site would
have crossed the site 79 minutes earlier than official sunset.

Among the NTSB conclusions was "that the aeronautical definition of “night”
does not adequately describe the conditions under which darkness exists in
mountainous terrain and, therefore, use of this term may not adequately
restrict potentially hazardous flight operations".

The NTSB recommended revisions in this regulatory area, to adequately
address these issues.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

They were
executing an approach that was not authorized "at night". [...]
Among the NTSB conclusions was "that the aeronautical definition of “night”
does not adequately describe the conditions under which darkness exists in
mountainous terrain and, therefore, use of this term may not adequately
restrict potentially hazardous flight operations".

The procedure should then not be authorized "after 79 minutes before
sunsett" or somesuch, if this is a special case. If this is a common
problem however, then yes, a more general solution (which may involve
regulatory or training changes) is called for.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

Ron Rosenfeld wrote:
On Tue, 08 Nov 2005 17:13:07 GMT, Jose wrote:


2. If the purpose of night flying regulations is to require the currency
of special skills when it is "dark", then the times should be adjusted to
reflect local topography. For example, ridges and mountains may cause
darkness to be present earlier than the official sunset time.

I think this is one of those places where judgement comes into play.
We're not talking about much of a temporal difference.

Jose


Well, there are legal, practical and safety issues also. On 29 March 2001
there was a fatal accident involving a Gulfstream at Aspen. They were
executing an approach that was not authorized "at night". "Official"
sunset occurred 33 minutes prior to the accident, so "official" night would
have occurred 3 minutes prior to the accident.

However, according to the NTSB calculations, the sun would have set below
the mountainous terrain about 25 minutes BEFORE official sunset time; and
the shadow for the ridge immediately to the west of the accident site would
have crossed the site 79 minutes earlier than official sunset.

Among the NTSB conclusions was "that the aeronautical definition of “night”
does not adequately describe the conditions under which darkness exists in
mountainous terrain and, therefore, use of this term may not adequately
restrict potentially hazardous flight operations".

The NTSB recommended revisions in this regulatory area, to adequately
address these issues.

The trouble is that you can NEVER write enough regulations to alleviate
poor judgement.


Matt

Ron Rosenfeld wrote:
On 8 Nov 2005 05:50:19 -0800, "Andrew Sarangan"
wrote:

What's wrong with saying "as published in the American Air Almanac"?

1. The American Air Almanac is out of print. It is not available on
amazon.com although it may be available elsewhere. However, it has
certainly not been updated in recent years.

Feh. I know it's hard to believe, but there are some things which
exist but you can't order from Amazon :-)

You can get current (2005 or 2006) editions of the Air Almanac
directly from the US GPO or UK Stationary Office, or from several
commercial suppliers, in print or on CD. See
http://aa.usno.navy.mil/publications/docs/ord_info.html for ordering
details.

If you're worried about the change in title from "American Air
Almanac" to "Air Almanac" (reflecting the fact that it is now
published jointly by the US Naval Observatory and the Her Majesty's
Nautical Almanac Office), you're obsessing over details even the FAA
would have trouble considering significant.

On Wed, 9 Nov 2005 22:40:53 +0000 (UTC), (Roy Smith) wrote:

you're obsessing over details even the FAA
would have trouble considering significant.

I'm in good company with the NTSB also writing that regulations and/or
guidance in this area is lacking.

However, obsessing over details is a well documented feature of this NG
:-))


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)