11/3/22
AIM
2. Precision Obstacle Free Zone (POFZ).
A
volume of airspace above an area beginning at the
runway threshold, at the threshold elevation, and
centered on the extended runway centerline. The
POFZ is 200 feet (60m) long and 800 feet (240m)
wide. The POFZ must be clear when an aircraft on a
vertically guided final approach is within 2 nautical
miles of the runway threshold and the official weather
observation is a ceiling below 250 feet or visibility
less than
3
/
4
statute mile (SM) (or runway visual range
below 4,000 feet). If the POFZ is not clear, the
MINIMUM authorized height above touchdown
(HAT) and visibility is 250 feet and
3
/
4
SM. The POFZ
is considered clear even if the wing of the aircraft
holding on a taxiway waiting for runway clearance
penetrates the POFZ; however, neither the fuselage
nor the tail may infringe on the POFZ. The POFZ is
applicable at all runway ends including displaced
thresholds.
FIG 5
−
4
−
29
Precision Obstacle Free Zone (POFZ)
c. Straight
−
in Minimums
are shown on the IAP
when the final approach course is within 30 degrees
of the runway alignment and a normal descent can be
made from the IFR altitude shown on the IAP to the
runway surface. When either the normal rate of
descent or the runway alignment factor of 30 degrees
is exceeded, a straight
−
in minimum is not published
and a circling minimum applies. The fact that a
straight
−
in minimum is not published does not
preclude pilots from landing straight
−
in if they have
the active runway in sight and have sufficient time to
make a normal approach for landing. Under such
conditions and when ATC has cleared them for
landing on that runway, pilots are not expected to
circle even though only circling minimums are
published. If they desire to circle, they should advise
ATC.
d. Side
−
Step Maneuver Minimums.
Landing
minimums for a side
−
step maneuver to the adjacent
runway will normally be higher than the minimums
to the primary runway.
e. Published Approach Minimums.
Approach
minimums are published for different aircraft
categories and consist of a minimum altitude (DA,
DH, MDA) and required visibility. These minimums
are determined by applying the appropriate TERPS
criteria. When a fix is incorporated in a nonprecision
final segment, two sets of minimums may be
published: one for the pilot that is able to identify the
fix, and a second for the pilot that cannot. Two sets of
minimums may also be published when a second
altimeter source is used in the procedure. When a
nonprecision procedure incorporates both a step-
down fix in the final segment and a second altimeter
source, two sets of minimums are published to
account for the stepdown fix and a note addresses
minimums for the second altimeter source.
f. Circling Minimums.
In some busy terminal
areas, ATC may not allow circling and circling
minimums will not be published. Published circling
minimums provide obstacle clearance when pilots
remain within the appropriate area of protection.
Pilots should remain at or above the circling altitude
until the aircraft is continuously in a position from
which a descent to a landing on the intended runway
can be made at a normal rate of descent using normal
maneuvers. Circling may require maneuvers at low
altitude, at low airspeed, and in marginal weather
conditions. Pilots must use sound judgment, have an
indepth knowledge of their capabilities, and fully
understand the aircraft performance to determine the
exact circling maneuver since weather, unique airport
design, and the aircraft position, altitude, and
airspeed must all be considered. The following basic
rules apply:
1.
Maneuver the shortest path to the base or
downwind leg, as appropriate, considering existing
weather conditions. There is no restriction from
passing over the airport or other runways.
Arrival Procedures
5
−
4
−
55