The in flight controversy comes from section 4 of 91.171 which is
highlighted below. The only time the Dual Check is mentioned it is preceded
by 'While in flight'
My question is then if that is the case then how does one check their VORs
when at an airport that does not have VOT or FAA approved VOR Check and
depart legal IFR?
I think the reg is being read wrong by those in flight advocates and section
(c) is not subordinate to paragraph 4 but stands on its own.
Scott
§ 91.171 VOR equipment check for IFR operations.
top
(a) No person may operate a civil aircraft under IFR using the VOR system of
radio navigation unless the VOR equipment of that aircraft-
(1) Is maintained, checked, and inspected under an approved procedure; or
(2) Has been operationally checked within the preceding 30 days, and was
found to be within the limits of the permissible indicated bearing error set
forth in paragraph (b) or (c) of this section.
(b) Except as provided in paragraph (c) of this section, each person
conducting a VOR check under paragraph (a)(2) of this section shall-
(1) Use, at the airport of intended departure, an FAA-operated or approved
test signal or a test signal radiated by a certificated and appropriately
rated radio repair station or, outside the United States, a test signal
operated or approved by an appropriate authority to check the VOR equipment
(the maximum permissible indicated bearing error is plus or minus 4
degrees); or
(2) Use, at the airport of intended departure, a point on the airport
surface designated as a VOR system checkpoint by the Administrator, or,
outside the United States, by an appropriate authority (the maximum
permissible bearing error is plus or minus 4 degrees);
(3) If neither a test signal nor a designated checkpoint on the surface is
available, use an airborne checkpoint designated by the Administrator or,
outside the United States, by an appropriate authority (the maximum
permissible bearing error is plus or minus 6 degrees); or
(4) If no check signal or point is available, while in flight-
------------------------------------------^^^^^^^^^^
(i) Select a VOR radial that lies along the centerline of an established VOR
airway;
(ii) Select a prominent ground point along the selected radial preferably
more than 20 nautical miles from the VOR ground facility and maneuver the
aircraft directly over the point at a reasonably low altitude; and
(iii) Note the VOR bearing indicated by the receiver when over the ground
point (the maximum permissible variation between the published radial and
the indicated bearing is 6 degrees).
(c) If dual system VOR (units independent of each other except for the
antenna) is installed in the aircraft, the person checking the equipment may
check one system against the other in place of the check procedures
specified in paragraph (b) of this section. Both systems shall be tuned to
the same VOR ground facility and note the indicated bearings to that
station. The maximum permissible variation between the two indicated
bearings is 4 degrees.
(d) Each person making the VOR operational check, as specified in paragraph
(b) or (c) of this section, shall enter the date, place, bearing error, and
sign the aircraft log or other record. In addition, if a test signal
radiated by a repair station, as specified in paragraph (b)(1) of this
section, is used, an entry must be made in the aircraft log or other record
by the repair station certificate holder or the certificate holder's
representative certifying to the bearing transmitted by the repair station
for the check and the date of transmission.
(Approved by the Office of Management and Budget under control number
2120-0005)
--
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Scott F. Migaldi, K9PO
MI-150972
PP-ASEL-IA
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wrote in message
nk.net...
SFM wrote:
Does a dual check of the VORs for use in instrument flight only count if
it
has been done while in flight? Or if you do it on the ground (document
it)
is that meet the FARs?
We had a fairly heated hanger discussion about this and I would like to
hear
some more opinions.
How do the airborne advocates read "while airborne" into the regulation?
The implicit requirement is that the station be received with a good
ident and no waving off flag. Granted, that would usually require you
be airborne, but certainly not always.