Transitioning to Visual Email this article |Print this article
The weather is right at minimums, and you've flown a perfect ILS with
the needles right in the doughnut all the way to decision height. But
you're not done yet! The toughest part remains ahead: transitioning
smoothly from instrument to visual references at DH so you can land.
Here are some ideas about how best to do this in both one- and two-pilot
situations.
June 3, 1996
byJonathan Regas
About the Author ...
Jonathan Regas flies DC9's for a major U.S. carrier. He has 10,000 hours
in over 60 aircraft types from Cherokees to MU-2s to Metroliners and
Jetstreams to Sabreliners, including 4,500 hours in DC9's. Jon lives
near Washington, D.C.
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.