| by |
Jonathan Regas |
One of the most difficult times in a pilot's workday is the transition
from purely instrument cues to visual cues needed to land from
an ILS approach. In my flying career, I have had the misfortune
to see such ham-fisted maneuvers at this critical point that I
thought I would share some ideas on the subject.
Transitioning to visual from an ILS is one of those times that
it's really advantageous to have two pilots in the cockpit. So
let's start off assuming we have a two-pilot crew; we'll talk
about single-pilot operations a bit later.
The non-flying pilot
A key concept here is that both pilots—the "flying pilot"
and the "non-flying pilot"—we'll call them FP and NFP—have
significant roles to play. So whether the NFP is a formal crewmember
or a pilot-buddy of yours who's just along for the ride, a formal
briefing of the NFP is in order, and should be done well before
commencing the approach.
Among the briefing items must be FAR 91.175(c)(3) that allows
us to continue descent below DH to a height of 100' above touchdown
zone elevation predicated on seeing only the approach lights.
It is legal, and properly done, a safety-enhancing method of approaching
the runway. To continue below 100' above TDZE, you must have
the red terminating or side row bars in sight, or else you must
see the runway, runway lights, runway threshold, threshold markings,
threshold lights, touchdown zone, touchdown zone markings, touchdown
zone lights, runway end identifier strobes, or VASI.
Keep it stabilized
A good stablized approach is vital to a good landing when the
visibility is right at minimums. Many regional airlines instruct
their pilots to approach with one flap setting, and once "visual"
with the runway, to drop the flaps down to the landing position.
What a waste of a good stable approach! While there may be some
concern about aircraft performance on a one-engine go-around,
I believe you should avoid such last-minute flap management procedures
that destabilize the approach right at the most critical moment.
Now assuming you are on-course and on-glideslope as we approach
decision height, the FP should stay on the instruments until specifically
told to look up by the NFP. Why? Because if the FP looks up at
DH to look for the lights or runway, a subtle deviation from glidepath
will result. Those seconds spent looking and deciding at DH will
almost certainly make for a poor approach.
So let the NFP tell the FP to continue the descent below DH (on
the gauges) based on seeing the approach lights and sequenced
flashers. The FARs say you can legally do this, and it will help
maintain the trajectory of the aircraft that the FP has been refining
since the outer marker.
When there is something worth looking at, the NFP can tell the
FP to "look up" along with a slight correction like
"2 degrees right".
Start to learn how the winds shift at your favorite airports just
around the base of a defined cloud layer or about 300' above the
airport due to surface friction. Be ready for an appropriate
correction.
Don't look up at DH
Don't look up untill the NFP can see either the runway or the
approach lighting system cross bars. I'll refer to these approach
light cross bars as "the roll bar". Why? Because it
is the first visual cue that allows an approximation of a visual
horizon. Take a good look the next time you fly and you can begin
to see that you can control the plane with reference to these
bars (and cross check of flight instruments) as your eyes become
accustomed to visual flight.
Just trying to fly by looking at the sequenced flashers and stationary
approach lights will lead you to the runway but most likely lead
you to overcontrol the aircraft until you can establish an outside
horizon reference. When you have established a visual reference
with the "roll bars" and/or the runway, say "I
am visual" to your NFP. At this point, the NFP should transition
to instruments and verify the flight path.
The NFP should make verbal callouts of deviations from the flight
path or reference airspeed: e.g., "one dot high, airspeed
decreasing." If your ops manual has standard phraseology,
use it. If not...CREATE IT! Now is not the time to misunderstand
a single word.
Phraseology
I won't try to give you a new vocabulary, except for the "roll
bar". Make one up that works for you. Here's an example
of what works for me:
At 1000 feet above touchdown zone elevation:
NFP: One thousand above, checklist complete.
At 500ft above TDZE:
NFP: 500 above, on-course, on-glideslope, Ref plus 5, sinking
700, no flags.
If you are off any of these targets, the NFP sould call them
out:
NFP: One dot high, one dot left of course, Ref minus 5, sink
400.
The NFP should also call out if any flight instruments or nav
instruments are not in agreement.
At 100 above dh:
NFP: 100 above, I am going outside.
At dh:
FP: At minimums.
If NFP doesn't have the approach lights in sight at dh:
NFP: Nothing in sight, go around.
FP: Going around.
If NFP does have the approach lights in sight at dh:
NFP: Approach lights in sight, continue descent.
FP: Continuing descent.
NFP: Roll bar in sight, look up.
FP: Looking up...roll bar in sight...I am visual.
NFP: I am inside.
NFP is now looking at flight instruments, calling flight path
and airspeed deviations, and ready to assist at any time with
a go around!
Single-pilot operations
For those of you who fly alone, here are a few ideas you can try:
-
Verbalize the NFP calls for yourself. Or if you have a trainable
right-seat passenger, press him or her into service to make altitude
calls and look for the approach lights.
-
If autopilot-equipped (and you should be for single-pilot
IFR), and if your flight manual permits, let "George"
fly a coupled approach and don't disconnect the autopilot until
100' above TDZE when you have the roll bars or runway in sight.
-
Stay on the gauges and don't look up until DH. If you see
the sequenced flashers, go back to the gauges and continue the
descent primarily on instruments to 100' above TDZE. During this
phase, try moving your eyes quickly between inside and outside,
as if you are including the windshield in your instrument scan.
Don't stop scanning the instruments until you're sure you have
solid visual reference.
Conclusion
The whole idea of this article is for both pilots to work together
until and after solid visual cues have been established by the
flying pilot. The decision part of Decision Height can be aided
by the 100'-above-touchdown-zone proviso of the FAR's based on
seeing the sequenced flashers of the approach lights.
Know what to expect from your crewmate—or from yourself, if you
are alone in the cockpit. If you have been "on the beam"
all the way through to DH, remember not to overcontrol or destabilize
the approach at the last minute.
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