N31AK POH, Pilots Operating Handbook

How the Systems work

Autopilot, also written: "a/p"


The "NavAid" autopilot is located just left of center, below the Airspeed Indicator. It serves as a turn and bank indicator with triangles marking the "Standard Rate"(2 minute) turns. LEDs turn on to denote the turn rate.

The turn indicator is driven by a electric motor, not vacuum. The NavAid is on whenever the Master and a/p's circuit breaker is active; there is no panel switch to turn off the autopilot.

The autopilot face contains the follows controls:

  1. silver, 3 place toggle switch which moves horizontally. left position connects a nav instrument to the autopilot. center position of the switch disables the autopilot right-most position enables the "wing leveler".
  2. The center knob is "fine adjust" for wing leveling.
  3. the right knob is "coarse adjust" for wing leveling. When the wing leveler is enabled, turning this knob will cause the plan to bank and turn.

When enabling the autopilot, it can suddenly jerk to try to accomodate the pilot's implied command. If its reaction is a problem, immediately disable the autopilot. If you're ok with its reaction, you can use the coarse adjust to get it to a desired attitude.

While the _face_ of the NavAid has the 3 controls just described, there is yet another source of control for the autopilot. At the top of the panel, just left of center (?) is a 2 position toggle labeled "Auto pilot trk". The left position chooses the Loran as the source of the Autopilot's signal; the right switch position chooses the VOR.

The CHT gauge

Bottom right of panel, Left side of shared gauge. Limit 425. Goal 350-375(?).

CHTs create a signal without drawing any energy from the battery; thus they don't need to be turned on/off. The physics of a CHT produce an electrical signal somewhat proportional to the temp difference between the "hot junction" and the "cold junction". The hot junction is at a cylinder head; the cold junction is wherever the bimetal conductors end. The CHT wires, made of the magic material, are "extended" with the same kind of material thru the firewall and into the passenger area. The cold junction does not have to use the expensive wires all the way to the gauge; normal wire will do.

Note that a CHT gauge must make some presumptions about the temperature of the cold junction since it really is given a signal representing the difference in two temperatures. One manufacturer (Westach) openly say their gauge numbering assumes a 75 degree cold junction.

When the plane was purchased, there was only one CHT sensor and it was attached to the port side plug, bottom, aft end of the engine. It didn't work well until it was removed, cleaned and re-installed.

I've since purchased 2 "type J"(?) thermocouples for CHT use. These have the "bayonet mount" which threads into the bottom of each cylinder.


The cover shouldn't be used if you think it might be windy; it'll use any dirt as an abrasive and scratch the surface.

At present the cover is folded from both sides while still on the plane. The two rolls meet somewhere over the canopy then the transverse parts are folded up towards the plane's centerline. The "rolls" are really discrete folds 80% the width of the black bag the cover will eventually be stowed in.

The EGT gauge

Bottom right of panel. Right side of shared gauge. Had trouble; working now.

The Fuel System

Low Fuel Warning LEDs

At the base of the panel, center, are two LEDs, one marked "left, 4" and the other is marked "right, 3". The appropriate LED turns on if

Fuel pump, fuel pressure gauge

Like the Challengers there are 2 pumps on the EZ. The engine has a mechanical pump and the builder added an electrical pump made by "Facet". The Facet is turned on/off by the switch on the right panel. It should be turned on for takeoffs, landings, and during fuel selector changes of tank. Typical pressure observed is ~7.2 psi (5-8 psi).

GPS (Magellan 315)

GPS (Garmin 196)

generally kept in a box in the office at the house in W.C.
black bag: 8x3x4", zippered.
remove main unit from top zippered area.
remove antenna from large, frontal area. attach.
// it has a BNC connector on one end, odd mountable thing on other,
// cable is a few feet long.
turn on/off: press light bulb button for a couple of seconds (?) and
press Enter when it asks you to agree to terms (VFR).
// it takes a few minutes to acquire satellites.
Page button cycles thru navigation screens.
Enter button says "yes" to questions.
Quit says "No" to question. If no question, it pops out of current level.
In/Out button adjust map zoom.
Menu button is access to many pages of Setup stuff.
NRST button shows nearest airports (first); has tabs for
looking at nearest VORs, NDBs etc.
-D-> button should go to the highlighted airport.

To check the battery's condition, press Page until battery display shown on same screen with large Lat/Long values. Batt timer field is elapsed time since batteries changed.
go to Menu pages: hit Menu key, If in Page area, it'll ask you if
you want a menu for the Nav screen you're on or whether you
really want the whole menu biz. Hit Menu key again to do Menus.

find moon phase: get to Menus, arrow dn to Celes.

define a line for use with HSI, I think you have to :

You'll now be on a screen showing empty waypoint names. Enter.
Now you'll be on a 3 tab screen (aviation,recent,user).
To change waypoint, arrow dn to name, Enter
Now use video game arrowing to redefine (choose) waypoint.
When you hit the final char. hit Enter and you'll stop editing the name. Then the OK button will be highlighted, Enter again.
When the line is defined, Quit and you'll see the line in the list.

To activate a route so it shows on HSI etc:

HI, Heading Indicator, Directional Gyro

Our HI, Heading Indicator (or DG), is a vacuum powered with _very_ low precession. There was a lengthy spell in 2007 when this unit's heading was not trusted because it didn't agree with the compass' indications. It turned out the compass was at fault.

The HI has been "tumbled" and will tumble again when turning 2G tight turns at 60 degrees of bank. When it tumbles it begins spinning as if driven by an electric motor. The unit can be "re-caged" by pressing in knob normally used for heading adjustments.


The "Hobbs" is the engine hour meter and is mounted just behind the pilot's head. It only counts time when the engine is running. It is used mainly to know when the next maintenance procedures are needed. The time shown on the Hobbs should be checked during preflight against the next maintenance time.

The Hobbs has no power switch so the pilot does not have to turn it on/off. Its value is customarily recorded at the start and end of a flight so the pilot's log book entry can be made.

The Hobbs meter is connected to an oil pressure switch on the firewall end, starboard side of the engine. When the oil pressure exceeds some very low value, like 4 psi, the switch connects the 2 terminal posts electrically. Wires #24 and #87 connect to the pressure switch. One wire is hot whenever the master switch is on. Effectively a relay inside the pressure switch connects the other terminal to the power connection when there's sufficient oil pressure.

The non-power, "signal" terminal on the pressure switch runs to the Hobbs "+" power pin (aft side of meter). The other Hobbs connection goes to ground.

The Hobbs meter was replaced shortly after buying the plane. 5/06. The oil pressure switch was leaking oil (1/07) and was replaced.


The intercom control is at the upper left of the panel. Consider leaving the knobs in their existing positions and just turning the device on/off from the toggle switch.

Panel Lights

For night flying, turn on the instrument panel lights at a switch named "Inst Lights" on the electrical panel at the far right. At the top of the panel is an adjustment knob which controls brightness, "Panel Lights".

The radios light themselves.

Landing Light

The landing light deployment lever is at the base of the panel. Move it downward, over center, to deploy it. Then flip on its power switch, "Landing Light", on the right hand panel. Retracting the Landing light requires pushing its lever to the upwards "over center" position.


The power knob is in center of device.

As long as it says it's searching for its GRI, it's not ready to navigate. Suggests receiver problems, or wrong GRI number...

The antenna is on the bottom of the plane, beneath the passenger's knees. The top vs bottom position is information needed by the configuration screens.

The Loran's UI (User Interface) expects you to choose what kind of thing you're looking for with the left knob.

Nearest airport function.
   Press -D- and CRSR simultaneously to display list of nearest
   airports, the runway lengths, distance...
   Rotate knobs (rt(?)) to choose one, hit -D- again(?).

Using it as a VOR
   enroute vs apch mode. determines the scale factors in 
   the display.

   I think you want to choose a fix to go to (fix=airport or
   VOR etc). When you go Direct to such, you're said to be
   "tracking". One display, chosen on the right half of the
   Loran, will act like an inexpensive VOR indicator, and 
   the bright dot, when centered, says you're on course. Left
   or right of center shows which way you have to go to 
   point at your destination fix.

   If you're going to an intersection (which isn't a fix),
   I believe there's an 'info' screen which'll tell you a
   bearing to a VOR in question, one which helps determine
   the intersection. When your bearing to this VOR equals the 
   bearing from VOR to intersection (or 180 from that), then
   you can turn onto that radial to follow it to the 

To setup your own "fix", you can add it to the "user" database.

Manifold pressure gauge

Hope someday to equate its readings to fuel consumption... (rpm/100 + mpInches) 10/3 - 85 = percent power 48 -> 75% 45 -> 65% power from someone named Cargo in canard-aviators

Marker Beacon

The marker beacons are 75Mhz transmitters located along the ILS approach path to a large runway. Controllers will sometimes ask for a position report as you cross one; approach plates will define a change in altitude at such a point.

The marker beacon circuitry must be turned on by the Bright/Off/ Dim switch near the top of the panel. "Dim" is a good setting for night; Bright in the daytime. To make sure you don't miss a beacon, you can turn on the sound generator to give you a short tone when you pass overhead. The sound is controlled by the switch at the upper left of the panel "marker beacon snd".

Oil Pressure gauge

Just below panel, right side. Typical values observed: 65 at low rpm, 80 psi otherwise.

Oil Temperature gauge

Just below panel, right side. Typically see 160 degrees. supposed to be 180. Scale has green and red marked. yellow between. Saw it uncharacteristically high 11/2006. Near red line!


Our oxygen is a 9 cu ft, Sky Ox system which is mounted in the right strake when needed. The gauge and control knob must be accessible to the pilot. I believe this should typically supply O2 for 8 hrs, 1 pilot.

If you expect a flight to be cold, consider bringing the O2 bottle indoors for awhile.

Signs you need more Oxygen:
- night vision // impaired over 5000'
- blue fingernails, headache, impaired memory for radio freqs etc.

Consider using the finger "blood oxygen monitor" which is kept in
the Sky Ox bag. The monitor is in a 3x2x2" orange box; the unit 
fits on your index finger. On the ground, my left index finger shows
97%, right finger 99% (with a hospital unit).

The O2 bottle mounts in the right strake with the wide velcro.

Turn small black knob counterclockwise all the way. Nearer to tank.
The gauge nearest the tank tells supply pressure which is
a measure of the quantity of o2 in the tank. Consider 
recording this value at the start of a flight.
- supply pressure Red -> low on o2.
- supply pressure 2000 -> tank full.  Tx table page 11.
Turn reg control valve, the big valve, to start flow. 
Clockwise to increase flow (flows only when canula attached).
Attach canula (BNC-like connnector).

The top gauge shows the flow rate and it bears 2 sets of numbers,
one microscopic. The larger numbers are your altitude in 1000'. 
The gauge markings are only suggested values. If you see your
fingernails turn blue, or the finger monitor so indicates, turn
up the flow.

A canula is only legal to 18000'; then you must have a face mask.

Tanks can be refilled at many FBOs. The AFD says whether an 
airport offers this service. Some airports charge a flat rate, 
regardless of bottle size. ($35 ?)

If you want a cigarette while using this, please let me watch
as you ignite the fireball.

Oxygen monitor

This is a 2"x 1.5" gray and orange, plastic gizmo which fits on a finger. It measures saturated blood oxygen and you typically use it to detect a difference over what your body normally has for blood oxygen.

So, on a nice day at home (or the hangar), sit down, put the thing on your finger and press the .25" oval, orange button to turn it on. It'll display something quickly, then some dashes, then a better value of "SpO2". Curl your finger over to read it (so you can also read the product's name on its orange bezel). The top number is your blood oxygen. Record it to compare with values seen in flight (Frank's read 98).

The bottom number is resting heart rate. I imagine this number goes up if your body is under stress.

This unit takes a lithium battery. To avoid running out of battery mid-flight, turn it on for a minute or two, check the value, then turn it off.

Radio (Comm)

Turn the radio on by twisting the left, 1/4" diameter, black knob clockwise til its white line points to the 2 o-clock position.

Radio (Nav)

Speed Brake

The speed brake should not be deployed at speeds over 90 kts. It turns out to be nearly impossible to wrestle it open at speeds near 90. If you deploy it then speed up, it CAN RETRACT ITSELF AND CLOBBER YOUR LEFT HAND. Be forewarned. I hear it hurts.


The tach has a switch on its face which is labeled only as "D". Have found that this appears to mean "Dim". Toggle it. Can't imagine needing to use the other setting.

The tach signal starts at the port side magneto (called the "left mag" since the engine is installed 'backwards' as a pusher). Three wires, red, yellow, black, twisted together, run to an inline junction near the bottom of the firewall. The new cable is almost the same color-coding except the orignally yellow wire becomes a white wire.

The 3 wires resurface behind the instrument panel and plug into the backside of the tach display. That connection must be made and checked with care as the pins inside the tach display can easily be pushed upwards where they don't make contact.


The transponder cannot be completely shut off. Turn its knob to Off when starting the plane (but you'll note that it lights up whenever the master switch is on).

On one (weird) occasion, a controller told me he was having troubles seeing my transponder. I power-cycled it using its knob and the controller then said it was ok. Not sure if power-cycling helped...

Occasional radio chatter between controllers and other planes suggest that transponders sometimes have problems and the conventional remedy seems to be power-cycling them.

The transponder uses a stubby little antenna underneath the nose, slightly starboard. It's 1 1/5" long, maybe 1/3" high, and white. A BNC connector feeds this antenna just forward of the pilot's right foot.

Turn Indicator (built into Autopilot display)

Lights one LED even when sitting still. The single LED just means it's powered; it is not an offset.

Note the triangles on either side of center. Those mark your "2 minute (standard rate) turns".

Vacuum System

There's a vacuum pump mounted slightly to port, near the firewall. It sucks air thru a black "heater hose" (5/8" ID), and exhausts that air into the engine compartment. The black hose connects to a metal tube at the bottom, port side, and this tube (?) wends its way thru the hell hole to the starboard side. Just foward of the rear seat control stick, near the passenger's right foot, is an access panel for the pressure regulator. The regulator has a sponge-like air filter which was "swallowed" in late 2006, apparently causing the vacuum pump to fail.

The regulator mounts to a custom "L" bracket which is apparently floxed to the fuselage wall. A large nut (~ 1.2" dia) mounts the regulator to the L bracket at the aft end of the assembly. Black hose sections mate the metal tubing to the regulator using hose clamps. The aft hose closes a plumbing gap of ~2" or more.

The front tube connecting to the regulator ends just to the right of the pilot's right knee. The tubing spreads out from there to connect to the instruments, vacuum gauge, and filter.

The regulator has an adjustment screw on its top. You're supposed to adjust it to ~5.2 while the engine is at 1700 rpm.

Warning Buzzer


There is a loud buzzer on the right panel. It can be shut off by pressing the square, red button at the aft-most end of that panel.

The buzzer is supposed to detect 2 bad situations:
- landing with the nose gear up
- taking off with the canopy unlatched.

If you're rolling on takeoff with buzzer, CANOPY UNLATCHED.
If you're slowing for landing, GEAR ISN'T DOWN.