Holdings
Holds are an
ambiguous rap when it comes to teaching as every
hold would have some unique characteristic to it.
Holds are basically circular patterns which keep
aircraft in a small space, allowing ATC to keep
traffic orderly and separated. In IFR training,
we commonly practice holding over a VOR. Holds
can take place in many places however. We can
hold over NDBs, we can hold at DME distances on a
specific VOR radial, we can hold at airway
intersections, we can even hold at GPS waypoints
with real-life GPS'. You'll frequently see holds
plotted on approach plates and STARs. Holds
require that you be VERY familiar and comfortable
with the operation of the VOR and interpretation
of the NAV equipment. Because VORs have 360
radials, we can be assigned to hold on any of
those. For our example, let's say that we have
been told to hold east on the 090 radial of the
Vero Beach VOR. So, we're going to head toward
the VOR along the 090 radial, which means we'll
be flying 270 TO. Standard holds are accomplished
with right-hand turns, so when we pass over the
VOR, we will make a 180 degree standard-rate turn
to the right and head back away from the VOR for
a specified time. We will then make another 180
degree standard-rate turn back towards the VOR.
This will result in a racetrack pattern as
depicted below.
You'll notice
that we have an inbound(heading towards the VOR)
leg and an outbound(away from the VOR) leg. I've
noted that the inbound leg should be 1 minute
long. Above 14,000ft, the inbound leg should be 1
1/2 minutes long. So, how are we going to make
sure our inbound leg is 1 minute long? Well, in a
no-wind situation, our time outbound should equal
our time inbound. So, let's start as we pass the
VOR inbound. We start our right 180 degree turn.
As we reach the abeam(the holding fix) point, the
TO/FROM flag will flip and we will start our
timer. WeOll then fly along until the timer
indicates 1 minute and then begin our right-hand
turn back inbound. If we make sure the turns are
standard rate, we would roll right out onto the
090 radial(270 TO). At that point, we will again
start our timer and see how long it takes us to
reach the VOR. We do whatever it takes to make
our inbound leg 1 minute long. If we found out
that it only took us 50 seconds to fly the
inbound leg, we would have to modify the outbound
leg by adding 10 seconds to it, flying outbound
for 1 minute and 10 seconds. Now, let's talk a
bit about how we navigate each leg. Since we're
holding along the 090 radial, we will set 270 TO
and TRACK the course inbound, keeping the needle
centered. Now, as we approach the VOR, the needle
will become more sensitive and start to move
off-center. Just continue to fly your heading
until the TO/FROM indicator changes and then
begin your turn. Now, as we turn outbound, what
are we turning to? Well, since we're not tracking
a radial outbound, we just turn to the reciprocal
heading. So, in this case, we would turn to a
heading of 090. The outbound leg is a
dead-reckoning leg, we just fly a heading for a
specified time(1 minute). So, like I said, if it
was a no-wind situation, it would look just about
like above.
There are three
entries we can make, called 'direct', 'teardrop',
and 'parallel'. The way we determine which entry
to make is by our heading to the holding fix.
Let's say that we have been given the holding
instructions discussed above and we're southwest
of the VOR. We would proceed direct to the VOR by
turning our HSI needle or OBS until it centered.
Let's say that it centers with an indication of
050 TO which would mean we're along the 230
radial. Our next step is to determine where we
are in relation to the actual hold that we're
going to fly. Take a look at the diagram below:
You can see the
various sectors for each entry. The sectors are
determined by adding 110 degrees to the holding
course on the non-holding side and subtracting 70
degrees from the holding course on the holding
side. Our holding course is the 090 radial, so if
we add 110 degrees, we get the 200 radial on the
non-holding side and by subtracting, we get the
020 radial on the holding side. We said above
that we were proceeding inbound along the 230
radial, so by looking at the diagram, we see that
we should make a teardrop entry. If we were
inbound on the 330 radial, we would make a
parallel entry and so on. Now, let's take a look
at what it looks like in the plane and from
above. We'll be flying the situation we discussed
above. In the first turn, we don't fly outbound
long enough, and overshoot the inbound leg.
