[Avodah] R' Nissim Karelitz's Beis Din: Kohanim cannot fly from Ben Gurion for the next few weeks

[Mike Miller via Avodah]

On Mon, Oct 31, 2016 at 5:10 AM, Zev Sero via Avodah
<avodah at lists.aishdas.org> wrote:
> On 30/10/16 07:25, Eli Turkel via Avodah wrote:
>> As we have have pointed out in the past numerous poskim state that
>> :ma-shehu" on Pesach should not be taken literally, i.e. a nano particle
>> of chametz is not prohinted. Similarly tumah rises as far as a person
>> can see with a naked eye. One woulkd need to check how high the plane is
>> over the Holon cemetery
>
>
> (a) Planes can be seen with the naked eye even at cruising altitude, if the
> weather permits.  (b) Even if that were not so, surely it's beyond all
> question that planes taking off from NTBG and flying over Holon can be
> easily and clearly seen from the ground.  It's only ten km from takeoff,
> after all.

I spent some time today looking at ADS-B data broadcast by airplanes
departing LLBG. Two things that may be of interest:

1. Altitude when passing near the cemetery is under 4000 feet. All
commercial airlines are easily visible at that height (and
identifiable). You can use Google earth to get a feeling for what the
cemetery looks like from that height, but's it's not that small.

2. Of the ten planes whose tracks I checked, 7 of them reported
passing outside of the cemetery's boundary, whereas 3 overflew it.
Note, however, that the planes that did not fly over the cemetery
passed within 100 feet of it, which means that (a) the wings may have
overflown it (is that a halachic problem?) and (b) we're getting very
close to the tolerances of the GPS and its reporting. Please do NOT
take this to mean that it is safe for a kohen to board a flight just
because it looks like many flights do not, technically, fly over the
cemetery. (I've tried to set up a bit of logging to see if I can get
some more data; we'll see if it works).

Note that this route is fairly restricted for a pilot. Flying further
south is not an option, as there is a reserved training area just
south of the cemetery (the "channel" is a few hundred feet wide).
Flying north of the cemetery would overfly Bat Yam, which I strongly
suspect is undesirable from a noise standpoint (obviously both of
these problems could be theoretically be solved, and I'm not taking a
stand on whether this is insensitivity to kohanim; just pointing out
that it's not trivial).

-- Mike Miller
Ramat Bet Shemesh (also home of the #1 contributor to FlightAware's
ADS-B collection
https://flightaware.com/adsb/stats/user/mikeage#stats-21920 and one of
the top contributors to FlightRadar24)