What is ...
P
Precision
As the name implies,
ATC provides Horizontal + Vertical guidance
A
Approach
For Approach use only
-
guidance starts
~ 8 nm from T/D
R
Radar
Need to be in radar contact and have 2-way communication
-
ATC provides guidance by looking on a precise & fast updating radar screen
Usage
-
MOSTLY USED IN EMERGENCY SITUATIONS
-
PAR is available at civil and military airports
-
DH only upon request by the pilot
-
range/dist. Information from touch down is given about once ea. Mile
(ex: 5mi..., 4mi..., 3mi... from touchdown) -
position updates/corrections are issued every couple of seconds or as required
-
missed approach instrument and communication failure will be issued
-
PAR usually has a 3 deg. Glide Path unless otherwise noted.
-
PAR usually consists of 2 radar units – one sweeps side to side & one that sweeps up and down → both sweep ~ once every second → almost no time delay
COMMON ATC STATEMENTS DURING
PAR - APPROACH
“coming up + on glide path” - for smaller planes
“on course/on glide path”
“going left of course/drifting → turn right …. (071)”
“going above/below glide path”
“slightly above glide path”
“going well above glide path”
PAR - Approach Profile
Differences between ...
PAR
-
Horizontal + Vertical guidance
-
comparabl to an ILS
-
controller radar screen shows detailed profile of horizontal & vertical (Glide Slope) position of the aircraft.
-
mostly used in Emergency situations
-
the pilot will constantly be advised how to fly/navigate.
ASR
-
Horizontal guidance ONLY
-
pilot is advised when to start descent to MDA (MDA will also be announced)
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pilot is advised when reaching MAP
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ATC radar sweep 360 deg./6 sec.
-
(10 rpm) → radar pic updated every 6 sec.
During both approaches the Pilot is given position reports relative to the RWY
AND is issued missed approach instruction in case of 2-way radio failure