part 135 alternate minimums
phi...@worldnet.att.net
forecast at ETA to be allowed as an alternate (i.e. the standard 600/2
for precision, 800/2 non-precision, or prescribed nonstandard minimums)
the same for part 135 as for 91?
phil cohen
phi...@worldnet.att.net
Larry Fransson
>
> Are the rules regarding what weather an alternate airport must have
> forecast at ETA to be allowed as an alternate (i.e. the standard 600/2
> for precision, 800/2 non-precision, or prescribed nonstandard minimums)
> the same for part 135 as for 91?
They are not necessarily the same. A particular operator (all three
that I have worked for) may have in their op specs an authorization to
derive alternate airport weather minimums that might differ from the
standard part 91 minimums.
Here is what my op specs say (it's page C-55 for those of you who want
to look it up in somebody else's op specs):
* For airports with at least one operational navigational facility
providing a straight-in non precision approach procedure, or a
straight-in precision approach procedure, or, when applicable, a
circling maneuver from an instrument approach procedure - a ceiling
derived by adding 400 ft to the authorized category I HAT or, when
applicable, the authorized HAA; a visibility derived by adding 1 s.m. to
the authorized category I landing minimum.
* For airports with at least two operational navigational facilities,
each providing a straight-in nonprecision approach procedure or a
straight-in precision approach procedure to different, suitable runways
- a ceiling derived by adding 200 ft to the higher category I HAT of the
two approaches used; a visibility derived by adding 1/2 s.m. to the
higher authorized category I landing minimum of the two approaches used.
Here's a note on what the FAA means by different, suitable runways. 13
and 31 are different runways even if they're the same piece of pavement.
If the wind is calm, they may also be different, suitable runways. If
the wind is 130 at 25, runway 31 is not a suitable runway.
Practically speaking, this is the effect. I fly out of Boeing Field
(BFI) which has an ILS to runways 31L and 13R. Let's say for the sake
of argument that 31L is not going to be suitable today. The minimums
for the ILS 13R are 250 and 1. Just a few miles away is SeaTac (SEA).
They've got parallel runways 16 and 34, with an ILS to both ends of both
runways. Minimums are 200 and 1/2. So if I'm flying to BFI and want to
use SEA as an alternate, the alternate minimums are 400 and 1. But if
I'm flying to SEA and want to use BFI as an alternate, the alternate
minimums are 650 and 2. Any other airport in the area with one ILS and
minimums of 200 and 1/2 would have alternate minimums of 600 and 1 1/2.
Additionally, the criteria for determining whether or not an alternate
is required are different. This applies to all 135 operators. Take a
look at 135.223(b) for those.
----
Larry Fransson (lfransson*aol*com)
Pilots are just plane people with a different air about them.