Re: Night flying times

On Tue, 08 Nov 2005 17:13:07 GMT, Jose <teacherjh@xxxxxxxxxxxxxx> 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)
.

Relevant Pages

  • Re: Night flying times
    ... ridges and mountains may cause darkness to be present earlier than the official sunset time. ... "Official" sunset occurred 33 minutes prior to the accident, so "official" night would have occurred 3 minutes prior to the accident. ...
    (rec.aviation.ifr)
  • Re: Night flying times
    ... ridges and mountains may cause darkness to be present earlier than the official sunset time. ... "Official" sunset occurred 33 minutes prior to the accident, so "official" night would have occurred 3 minutes prior to the accident. ... currency are adequate? ...
    (rec.aviation.ifr)
  • Re: english words absorbed into Asian languages during WW2
    ... places, rural regions" (Chapman). ... the mountains are uncultivated, unpopulated, uncivilized and difficult ... It is no accident that "hillbillies" live there. ...
    (sci.lang)
  • Re: Night flying times
    ... of special skills when it is "dark", then the times should be adjusted to reflect local topography. ... ridges and mountains may cause darkness to be present earlier than the official sunset time. ...
    (rec.aviation.ifr)