Instrument Flying

Document Sample
Instrument Flying Powered By Docstoc
					Instrument Flying
 Chapter 24 of the Flight Training Manual has an excellent section on instrument flying. Despite
that each year many students do not develop a good instrument scan. All too often students have
a scan that is fatiguing, and results in less than ideal accuracy of flight. Most commonly this is
due to not using the Attitude Indicator (AI) properly.

 The thing to realize is that the AI must be scanned carefully. Your eyes must take in both the
pitch and bank pointers. Many people only look at the center of the instrument and never at the
top where bank is indicated. To clarify this point go to the simulations section on the Intranet site
and watch the simulation called Selective Radial Scan.

Attitude Plus Power Equals Performance
 A good instrument pilot realizes that there is only one attitude and one power setting that will
provide the desired performance at any given moment. In other words if you wish to fly at 85
knots there is a specific attitude and a specific power setting you must use. If you use too much
attitude the airplane will fly too slowly and conversely if the nose is too low the plane will fly
too fast. If you have too much power the airplane will climb, too little power and it will descend.

For those mathematically inclined the relationship between thrust and climb is:

Sin(climb angle) = (Thrust – Drag) / Weight

 When you climb and descend at a constant airspeed your angle of attack does not change
significantly. Therefore as you raise and lower the nose your angle of climb changes the same
amount as your attitude changes. Knowing that you can predict how much the vertical speed will
change; the formula is:

Vertical speed = sin(c) x TAS x 6080 / 60 [ in feet per minute]

 For a C-172 (or any airplane flying 100 knots) a 1° climb results in 177 feet per minute. In other
words every one-degree pitch changes your vertical speed by 177 feet per minute. For an
airplane flying 150 KTAS (B-95 speed) the formula produces 265 fpm.

 When you slow down or speed up in any airplane you must change angle of attack (AOA). For
an airplane flying at 100 knots 1 degree of AOA change is required for 10 knots airspeed change.
But, as you fly faster less AOA change is required. For example if you are flying 150 knots and
wish to make a 10 knot speed change it will require only about ½ a degree AOA change.

Power changes and airspeed
 Think of the propeller as a screw, turning through the air like a screw turns through wood. You
move forward with each revolution. If an airplane flies 100 knots with a FIXED PITCH propeller
turning 2,500 rpm we can say:

       100 knots = 2,500 rpm
       10 knots = 250 rpm
        1 knot = 25 rpm

 Using the above method you can come up with a formula for how much to change the rpm to
change airspeed in any airplane you fly with a fixed pitch propeller. You just need a known
starting point, which you get by flight testing, or consulting the POH.

 For airplanes with a constant speed propeller the above method doesn’t work because the
propeller blade angle keeps changing. Instead you need a rule of thumb for manifold pressure
change. Our recommendations are below.

Rules of thumb
Based on the above theory we recommend the following rules of thumb:

                Change                  Result
C-172           1-degree pitch          ~ 200 fpm

                 1-degree pitch          10 knot speed change

                 100 rpm                 ~ 5 knot speed change

B-95             1-degree pitch          250 fpm

                 0.5-degree pitch        10 knot speed change

                 1.0 inch MP change      5 knot speed change

                 1.0 inch MP change      100 feet per minute

NOTE: When using the rules above they can be proportioned.


        If you want to slow down 10 knots in a C-172 and make NO CHANGE to vertical speed
        you will need to raise the nose 1 degree and reduce power 200 rpm.
        If you want to climb at 100 feet per minute and make NO CHANGE to airspeed in a C-
        172 flying at 100 knots – raise the nose 0.5 degrees and increase power 100 rpm.
        If you want to climb at 100 feet per minute and are willing to do that by sacrificing
        airspeed then (for the C-172):
            o Pulling back so that you lose 5 knots will produce a 100 fpm climb (NO POWER
        If you are on approach and a bit high pushing forward to increase the VSI by 100 fpm
        will cause the airspeed to rise by 5 knots (in a C-172)
 In addition to the above rules of thumb that relate to the “attitude plus power equals
performance” concept there are several other technique related rules of thumb the instrument
pilot should know:

   1. When turning roll out of the turn when the heading is half the angle of bank from the
      desired heading (i.e. for a 20 bank turn roll out 10 before your heading.)
   2. When climbing or descending, start to level off 10% of your VSI before the altitude (i.e.
      if climbing 500 fpm, start to level off 50 feet from your altitude.)
   3. Extending the gear is the equivalent of throttling back 5” of manifold pressure. (i.e. is just
      enough to start a 500 fpm descent.)

Tips for Smooth Full-Panel Instrument Flying
You should have already read the section on selective radial scan in the Transport Canada Flight
Training Manual. This section provides a few additions tips to keep in mind.

 Keep a light touch on the controls. In order to do that you must keep the airplane in trim.
Trimming is NOT an afterthought; it is an important technique that must be done properly. Here
is how to do it, step by step:

    1. When leveling from a climb or descent slowly set the elevator trim to approximately the
        required setting while waiting for cruise speed to settle it. DO NOT wait to trim.
    2. Anticipate rudder inputs when leveling from climbs and descents or changing airspeed
        and make a tiny rudder trim adjustment in anticipation.
    3. Once cruise speed is established always trim in the following order: Elevator trim, then
        rudder trim, lastly aileron trim.
    4. When setting elevator trim take a firm grip on the control wheel and move the pitch
        attitude to the desired attitude – then let go briefly. If the nose moves up or down take a
        firm grip and gain and move the nose back where it belongs; then adjust the elevator trim.
        Once more release the wheel briefly and if the nose move repeat the above process until
        the trim is perfect.
    5. Confirm that airspeed has stabilized before you consider step 4 to be complete.
    6. AFTER step 5 – hold the wings level and pull your feet up off the rudder pedals. Check
        the heading indicator; if the airplane drifts off its heading adjust the rudder trim. Repeat
        until the airplane flies straight.
    7. AFTER all the above; release the control wheel. If the airplane rolls adjust the aileron
 Once you have the airplane in trim, as described above use a “pulsing grip” to prevent yourself
from tensing up on the controls. The pulsing grip involves holding the controls as firmly as is
needed (discussed below) then forcing yourself to relax your grip to almost nothing for one or
two seconds a few times per minute. This variable pressure grip prevents you from gripping
tighter and tighter and tighter, which is what you will tend to do under stress.

 How tightly should you hold the controls? The answer depends on the type of airplane you are
flying. A C-150 is so light you can fly it with two fingers. But a twin, such as the Travelair
requires your full hand to be on the control column. The C-172 is light enough to fly with two
fingers in cruise, if there is no turbulence; but most of the time you need two or three fingers,
plus your thumb to produce enough force to control the airplane. Most airplanes have a grip with
a shape similar to a gun grip. You have seen cop shows on TV and have never seen someone
hold a pistol with two fingers while trying to aim it at someone. So, DON’T attempt to do that
when flying. Hold the control wheel with your thumb on the thumb rest and two to four fingers
curled around the grip – then use the pulsing grip as described above. (Only in cruise, when
conditions are smooth, should you ever cup the wheel with thumb and one finger at the lower left

 Perhaps the most useful piece of instrument flying advice we can give you is to fly the know
attitude. For example, it normally takes about 7 degrees nose up for a cruise climb – so fly 7
nose up if you are doing a cruise climb. That should be obvious, but in fact people will often
throw the attitude all over the place while chasing minor fluctuations in airspeed due to
turbulence, wind shear, etc. The same advice applies to every aspect of flight. So get to know
what attitude you need for:

       Climb at Vy (right after takeoff)
       Cruise climb
       Downwind / procedure turn
       IFR approach configuration – at 500 fpm descent
       IFR approach configuration – in level flight

 The secret to good instrument flying is to know the attitudes above and USE THEM. After
establishing an attitude for several seconds, if you notice that you are drifting off the desired
performance (whether that is a certain altitude, airspeed, or descent rate) make a slight
adjustment in you “target” attitude. But DO NOT chase the airspeed or vertical speed around. A
good instrument pilot is a pilot who is always targeting a particular attitude. For example: in a
climb you may start by targeting 7 nose up attitude and desiring 85 KIAS. After a few seconds
you note that the airspeed is bouncing around a bit in turbulence but on average is 80 KIAS. You
therefore adjust your target attitude to 7.5 - and re-trim slightly to accomplish that.

 In the B95 we establish a range of cruise climb speeds from 105 to 122 KIAS. In all cases we
desire a vertical speed of at least 500 fpm. To accomplish this you must establish a certain climb
attitude (usually 6 nose up). If your speed is in the desired range and the VSI is adequate simply
hold the attitude and allow any airspeed fluctuations that may occur in turbulence to average out.
If the average VSI is too low or the airspeed is outside the acceptable range then adjust the
attitude, say to 7 nose up – but do not chase every little airspeed fluctuation – fly the attitude.

Tips for Leveling Off
 In the rules of thumb above we recommended starting to level off from climbs and descents
10% of your VSI before the altitude. For example, if you are climb 700 fpm, start to “push over”
into level flight at 70 feet below your assigned altitude. There are a few additions tips for this
procedure however.

 Leveling off from a climb or descent is one of the most difficult challenges in instrument flying.
The reason is that the pitch and power changes cause yawing moments that will swing the
airplane off its heading just at the very moment the pilot is inherently distracted by the altimeter
and VSI. Consequently, to do a good job of leveling off we must scan all six primary flight
instruments, plus the power instruments (tachometer and manifold pressure gauge). This is a
very challenging task, so you must practice, practice, and practice.

 We define a “good job” of leveling-off as one where the climb or descent stops exactly on the
assigned altitude, the heading does not change (assuming straight flight) and the power is set
accurately, but at the correct time. None of the preceding will be possible if trim is not also used
appropriately. Let us know discuss the details.

 The easiest level off procedure is one where the climb or descent airspeed is the same as the
desired speed in level flight. For example, in the circuit we may be climbing at the same speed
that we intend to fly downwind at. Another example is on an IFR approach where we may make
a “step descent” involving leveling off with no change in configuration or airspeed, then
resuming the descent, again with no change in configuration or speed. In all these cases the pitch
attitude and power must be change in unison. In other words at 10% of the VSI before the
altitude the pilot begins to simultaneously change power and pitch attitude from the
climb/descent settings to the level flight settings. The hard part is synchronizing the two. The
new attitude and new power setting must both be established simultaneously. If, for example,
you lower the nose quickly but reduce power slowing when leveling for downwind the airspeed
will increase, then fall back to the desired value (not what we want). So, you must ensure that the
new attitude and new power setting are achieved simultaneously. Another example is leveling
off on an IFR approach. You must start to add power and raise the nose at 10% of the VSI before
the new altitude. Many pilots raise the nose faster than they add the power. Consequently, the
airplane loses some airspeed as it levels off.

 In the situations described above the change in power setting causes a slight “swing” of the
nose. When reducing power to start a descent or level off from a climb a bit of left rudder (or
reduction or right rudder) will be needed. Because the airspeed does not change the angle of
attack also does not change so the swing is quite minimal, and easy to control. Assuming the
pilot has taken the advice above and knows the required power setting and attitude it should be
possible to drop the ASI from the scan for a moment and check the HI and TC in addition to the
obviously necessary ALT and VSI for a few seconds. This will ensure the airplane remains
straight. After a few seconds the pilot should then find it easy to check the ASI and confirm the
airspeed has not changed.

 Most light airplanes climb at a speed considerably slower than cruise speed. Consequently we
must accelerate after we level off, from climb to cruise speed. Pilots are familiar with the saying
“attitude, power, trim” to describe the sequence of actions, but many do not do it properly.
Unfortunately the simple saying above is a bit misleading in this situation because the real
sequence is more like “attitude, trim, attitude, trim, attitude, trim, attitude, power, trim.” That
doesn’t exactly roll of your tongue though, does it? The thing to remember is that there should be
two or three “attitude, trim” cycles before the final “attitude, power, trim.” The next paragraph
give a step by step analysis of leveling off for cruise.

 Assume you are climbing at 105 KIAS with 6 nose-up and your vertical speed is 800 fpm. You
wish to level off and cruise at 150 KIAS. Here is what you should do. At 80 feet below you
altitude lower the nose to 3 nose up (half the climb attitude). You know the actual vertical speed
of the airplane will change almost instantly but the VSI will lag. You also know the ALT will
slow down, but you also know the airplane will start to veer a bit right if you don’t apply some
left rudder. So you should can from your AI to the HI and ALT primarily, with a glance or two to
the ASI to confirm it is starting to rise and the VSI confirm it is starting to drop. Once the
airspeed starts to rise you MUST put is a “smidge” of nose down elevator trim or back pressure
will develop in the control wheel. At 40 feet below your altitude lower the nose to 1.5 nose-up
(half again). Continue to trim slowly as the airspeed builds and check the HI and TC to confirm
you are going straight. If you have done things correctly your airspeed should be getting quite
close to the desired cruise speed as you reach your altitude. If that is the case you can lower the
nose to zero pitch as you reach the altitude and the airplane will fly level (remember that if your
airspeed is below cruise you will need a slight nose up attitude to stay level). Once your airspeed
reaches the desired cruise speed set cruise power. Remember that the reduction of power must be
accompanies by a slight left rudder input, so check the HI and TC as you reduce power. You
should find this relatively easy to do if the elevator trim is reasonably set, as encourage above.
But if you have unwisely chosen not trim the elevator before this point you will either find the
nose “springing up” as you check the HI or, your concentration of the pitch attitude to prevent
the nose spring will keep you from checking the HI and you will go off your heading.

 To recap the above, you trim at least two of three times as the airspeed increases from climb to
cruise speed so that pressure on the wheel is light as you make the final power adjustment upon
reaching cruise speed. If you do things properly the nose goes down in increments from climb
attitude to zero as the airspeed increases.

 The above describes what should be done. What is actually done in many cases is more like: At
80 feet below the attitude is lowered all the way to zero – airspeed starts to rise rapidly and since
the pilot does not trim the back pressure is soon so great that the nose “flies up” to more than the
original climb attitude. The results is a “zoom” through the assigned altitude and a desperate
pilot reducing power and pushing forward to get back to the assigned altitude. Don’t let this be
you. Read the above and practice until you can do it smoothly and accurately.

 A final note should be made about an often-used technique, which is to purposely overshoot the
assigned cruise altitude when climbing and then descend back to cruise altitude. For example if
you are assigned to level off at 8,000 feet you actually level off at 8,100’, then leaving climb
power on you “dive” back to 8,000’ and consequently accelerate rapidly to, or even beyond
cruise speed. Many pilots feel they can get the airplane up to cruise speed faster this way. In
some airplanes this technique works quite well, in most airplanes it is a waste of time however. If
only works if the CDp in climb is substantially higher than in cruise (as for example with certain
laminar flow wings). Theory notwithstanding, we do not use this technique at Selkirk College. It
is presented here only to make you aware of alternative viewpoints that you may encounter after

Partial Panel Instrument Flying
 Read the section on partial panel flying in the Transport Canada Flight Training Manual, pages
158 to 163.

 “Partial panel” simply means flying with some instrument not working. It could be any of the
six primary instruments (ASI, AI, ALT, TC, HI, and VSI).
 In the C-172 the HI and AI are both powered by vacuum from an engine driven vacuum pump.
These pumps fail fairly often so practicing flight with these two instruments failed provides the
greatest level of safety. In Selair’s Beech Travelairs the AI is vacuum driven but two of the HIs
are electric, while the third is vacuum driven. In such a system failure of all the HIs is unlikely.
The AI could however still fail so we practice partial panel with no AI regularly.

The discussion below is specifically directed to flying with both the AI and HI failed.

Recognizing Instrument Failure
 Instruments can fail, or the power source that drives them can fail. If both the AI and HI fail
simultaneously we of course would suspect the power source. If only one fails then the problem
would likely be in the instrument itself.

 Ideally the airplane would be equipped with a warning light or flag that would advise the pilot
that the power source has failed. GOSQ used to have a low vacuum warning light, but it is now
unserviceable. All our other C-172s have no warning light, so it becomes the pilots’
responsibility to monitor the vacuum gauge in flight. It is highly likely that if the vacuum pump
failed you would not notice the gauge drop to zero until the AI and HI began to operate
incorrectly however. So, what indications will you get, and what should you do?

 When the AI looses power it slowly banks over and drops to a nose down attitude. You have
seen this “no power” indication every time you get in the airplane, before you start the engine. In
flight you will be tempted to follow the slumping instrument and put the airplane in a spiral dive.
If you follow the failing instrument then to you the attitude indicator would look “normal”, but
the airplane would actually be entering a spiral dive. How will you know? Your altimeter and
VSI will show a rapid descent developing, and the airspeed will start to rise. The TC will also
show a turn, even though the wings look level on the AI. Psychologically you may feel that
everything except the AI seems wrong. When these indications arise you must immediately
recognize an AI failure and switch to a partial panel scan (as described in the Flight Training
Manual pages 158 to 163).

 AFTER you recover from the spiral dive you should check the vacuum gauge to confirm it has
dropped to zero. Once confirmed you should stop relying on the HI for heading and start using
the compass and timed turns (see below). If the vacuum gauge is normal then perhaps only the
AI has failed so you should check the HI against the compass and use it with caution until you
confirm that it is still working properly.

 During flight training your instructor normally covers the AI and HI to simulate partial panel.
This eliminates the whole scenario above. However in the simulator we can give you a more
realistic failure and you may wish to practice it on your own by having your partner spring an
unannounced vacuum failure on you.

 It is an excellent idea to cover the failed instruments because they will distract your scan if you
don’t. To cover the AI and HI take a piece of paper and fold it until it is the right size to cover
the two instruments. Poke a whole in the middle with your pen then place it on the knob of the
AI. (Note that Selair C-172s have an aluminum instrument cover in the map box that works very
Partial Panel Scan
 Assuming that the only instruments available to us are the compass, ASI, ALT, TC, and VSI we
must devise a scan that keeps the airplane under control and allows us to navigate from IMC
conditions to a safe landing. As part of your Commercial Pilot training you must show
competence at cruising flight on partial panel and the ability to make a timed turn to a chosen
heading. But as part of your IFR flight test you may be required to descend from cruise and
conduct an entire IFR approach on partial panel. So it is important that you develop the required
skills. Regardless of flight test requirements if you are on partial panel in IFR flight you are
facing the task of completing an approach with all the requisite speed and configuration changes,
not to mention radio navigation without the aid of the AI and HI.

 Just as on full panel your scan must be selective. In full panel flying we emphasize different
instruments in our scan for cruise, climb, turns, etc. The same is true for partial panel flying. The
required selective scans are described quite well in the Flight Training Manual – read them now.
The information below expands on that information.

 We will now start our discussion of partial panel scan by specifying what information we get
from the available instruments:

Airspeed Indicator (ASI)                        Airspeed changes with climbs and descents
Altimeter (ALT)                                 Altitude changes when power or pitch
                                                attitude change
Vertical Speed (VSI)                            Vertical speed changes when power or
                                                pitch attitude change
Turn Coordinator (TC)                           The turn coordinator deflects when the
                                                airplane is turning. The airplane could be
                                                yawing or could be in a coordinated turn
                                                (i.e. banked.) We know it is coordinated
                                                turn if the ball is centered.
Compass                                         Gives us headings but is subject to turning
                                                errors and acceleration errors.

Proxy for Attitude
 Notice from the table above that we have NO INSTRUMENT that directly gives us the
airplanes attitude. To control the airplane we MUST know the attitude (and power) therefore we
need substitutes or “proxies” for the pitch and bank information that we normally get from the
attitude indicator. The following paragraphs explain what proxies are available. Later we will
discuss which ones we should select in a given situation.

 If you leave the power constant then airspeed tends to decrease if you pitch nose up and increase
if you pitch nose down; this is the same phenomenon you experience when driving your car up
and down hills. Therefore airspeed is a “proxy” for pitch attitude.

 If you leave the power constant the airplane tends to climb if you pitch the nose up and descend
if your pitch the nose down. Therefore the ALT and VSI are proxies for pitch also.
 If you are banked the airplane turns unless it is slipping. Therefore, if we avoid slipping the turn
coordinator is a proxy for bank. It is important to remember that when we make quick power
and/or attitude changes such as starting a climb or descent that the airplane tends to slip;
therefore we may be “fooled” into thinking the airplane is banked if we rely on the TC. It should
be clear that using the TC as a proxy for bank will require some finesse.

 With all the above in mind you should read the descriptions of partial panel scan for straight and
level flight, climbing, descending and turns in the Flight Training Manual (starting on page 158).

Timed Turns
 The compass is the only heading indicator available when flying partial panel; unfortunately it is
very difficult to use due to turning errors and acceleration errors. Read about compass errors
starting on page 2-22 of the Transport Canada Instrument Procedures Manual. We can only get
an accurate heading indication if we are NOT accelerated. Therefore all turns on partial panel
must be timed using the turn coordinator.

 In Selair airplanes we use the stopwatch built into the ADF for timing. To use the stopwatch
first set the ET mode by pushing the second button from the right until ET appears. Then push
the right button to start the stopwatch. To time a turn first determine how many seconds you need
to turn. When ready press the stopwatch just before rolling into the turn. Continue to turn until
the time is completely expired and then start to roll out. The entry and exit of the turn will cancel
each other if you roll at the same rate when beginning and stopping the turn.

 To calculate the amount of time required for a rate one turn you must know that a rate one turn
is defined as 360 in two minutes, which is why the words “2-minute” are printed on the face of
the instrument. This equals 3 of heading change per second. It is more useful to memorize:

       1 minute for 180 degrees
       10 seconds for 30 degrees
       3 (or 3.3) seconds for 10 degrees
       7 seconds for 20 degrees

 Whenever you are facing a timed turn break the turn into segments consisting of the above 10,
30, and 180 degree segments. Use a handy reference such as the ADF or OBS to help you do
this. For example count out the number of 30-degree segments (counting 10, 20, 30, 40) then add
the number of 10-degree segments (counting either 3 or 7). The total is the time for the turn (with
no complicated dividing required).

Unusual Attitude Recoveries
 The Transport Canada Flight Training Manual gives a fairly good description of unusual attitude
recovery procedure starting on page 161. Please read it before reading below.

There are three possible unusual attitude scenarios:

   1. Nose up
   2. Nose down
   3. Spinning / stalled
 The fact that the airplane is in an unusual attitude of some sort is usually first indicated by a
sense of disorientation. Typically the pilot has been distracted, perhaps trying to find a pencil
that fell on the floor, or refolding a map. When s/he looks back at the instruments things are not
as they should be. The situation could also be the result of delayed recognition of a vacuum
pump failure (discussed above), an autopilot malfunction, a wake turbulence encounter, or any
number of other situations that put the airplane in an unusual attitude.

 Once you realize you are in an unusual attitude the first instrument to check is the ASI. It is the
TREND of the ASI that you are checking (i.e. is it increasing or decreasing and how fast is it
changing). If it is “normal” i.e. steady at the speed you are supposed to be at then you probably
are not in an unusual attitude. Perhaps your AI has failed, and that fooled you, or you have
vertigo. Cross check the turn coordinator (TC) to confirm you are flying straight and if you are,
trust your instruments while you sort out the situation.

When in an unusual attitude the ASI will be the first and most reliable instrument to inform you.
There are three possible indications:

Indication                    Interpretation
ASI decreasing                Nose up attitude
ASI increasing                Nose down attitude – spiral dive
ASI low and constant          Stalled – possibly spinning.
 The more rapid the rate of change of airspeed the more extreme the attitude is!

 The T.C. Flight Training Manual explains how to recover from each of the above situations
(pages 161 to 163). Below are a few extra points to consider.

 When you recover from a nose up attitude you should apply full power, push forward on the
control wheel and roll the wings level referring to the TC. You stop pushing forward when the
airspeed needle stops decreasing. It is important to think about the trim of the airplane at that
point. If the airspeed stops at a low speed you will be flying level in a relatively nose high
attitude. The airplane is most likely trimmed for cruise however, so if you were to let go of the
controls the nose would “flop down.” Therefore you must anticipate that you will need a bit of
backpressure, just after you finish pushing forward on the controls. Failure to realize this is the
most common reason why people over control during this scenario.

 When you recover from a spiral dive you pull ALL POWER OFF then roll the wings level using
the TC. You then pull back until the airspeed stops increasing. Typically you are at a speed
greater than cruise speed at that point and flying with no power. Common sense tells you that the
airplane will be in a modest descent at that point, so you must then use the altimeter to level the
airplane off by pulling back a bit more. Failure to realize this is the reason many people under
control in this scenario.

 If the airspeed is low but constant you could have a failed ASI. If altitude and heading (TC) are
constant and VSI rate is normal suspect a partially blocked pitot tube. (Turn on the pitot heat and
check your copilot’s ASI if available.) When airspeed is low and the airplane is losing altitude
rapidly you are probably stalled. If the AI, TC, and HI show rapid turning and rolling you are
spinning. If not you are “mushing.” Mushing can occur, especially in a large airplane, following
a wind shear encounter on approach. Execute the wind shear procedure from your POH. If the
airplane is spinning execute the spin recovery procedure (this is much more likely than mushing
in a light airplane).

 In your training you will have one or two opportunities to experience a spin under the hood. Be
sure to take the time to notice that the airspeed remains low throughout the spin – i.e. it does not
increase until you recover, even though the nose is very low in the spin. Once you do recover the
first indication is that the TC “snaps” off the stop – but don’t expect it to perfectly center.
Momentarily thereafter the airspeed starts to increase rapidly. Once you see the airspeed increase
you know you are no longer spinning so you should release the rudder to neutral and recover
from the dive, just as in the nose down attitude recovery discussed above.

Loss of Control – Spatial Disorientation
 Every year a number of pilots lose control of their airplanes and crash out of control, often
striking the ground in a near vertical attitude either spiraling or spinning. A lot of these are non-
instrument rated private pilots who flew into IMC conditions on VFR flights, but sometimes
even instrument rated pilots are involved in such accidents. Sometimes the accidents result from
a partial panel situation, but sometimes spatial-disorientation is the cause. When spatial
disorientation is the culprit the pilot actually puts the airplane into the spin or spiral while
attempting to control the airplane. For example a pilot can become so panicked by a “falling”
sensation s/he is experiencing that s/he pulls back as hard as possible on the control column
(subconsciously attempting to “hold the airplane up”) and thereby stalls the airplane. A spin
normally follows and the pilot, who may realize that the airplane is descending toward the
ground, pulls as hard as possible to stop the descent thereby keeping the airplane in the spin until
the airplane hits the ground. Alternately the backpressure may tighten a steep spiral dive so much
that the pilot blacks out1. Either way the result is the same.

 If you have never had vertigo you may not be able to believe that the above can happen, but
every pilot will get at least mild vertigo at some time or another. You must however ensure that
it never reaches the point of blind panic that causes you to pull the airplane into a spin or a tight
spiral. To avoid extreme vertigo avoid flying when ill, stay well rested and practice IFR flight
regularly. If you start to experience vertigo try to stay relaxed. Engage autopilot if available. If
not, then concentrate on the AI. Pay attention to your body – control your breathing rate, and
don’t let yourself tense up. Relax your grip on the controls and keep the wings level with gentle
smooth nudges (some people like to use the rudder for this, but others find the yawing makes
vertigo worse and prefer to use the ailerons, but gently). Concentrate on keeping the wings level
and try to let the airplane natural stability work for you. As long as you keep the wings level the
airplane won’t dive rapidly toward the ground – so avoid large forceful control inputs. Most
importantly, trust the instruments. You may feel like you are in a turn when you are actually
flying straight – confirm you are straight with the TC and gently roll to level.

 Most vertigo/spatial disorientation encounters can be ended without escalating into an unusual
attitude recovery if you take the advice given in the preceding paragraph. If however you wind

 A distraction such as tuning radios, folding maps, etc frequently result in the airplane starting into a spiral dive if
not on autopilot. Pilots are supposed to roll the wings level before pulling out, but in a panic the pilot may only pull.
up in an unusual attitude follow the unusual attitude procedure described above. Once you have
“gross control” reestablished follow the advice in the preceding paragraph until the vertigo clears
or you get out of IMC conditions.