a.  Icing

        The presence of ice has a significant impact on aircraft performance.  It disrupts the smooth flow of air over an airfoil, thereby decreasing lift, increasing stall speed, and increasing drag.  The buildup of ice on various structural parts of the aircraft an result in vibration, causing added stress to those parts.  Especially true in the case of propellers an rotors, which are delicately balanced.  Even a small amount of ice, if not distributed evenly, can cause great stress on the propeller and engine mounts.

        Types of frozen moisture:

        Ice Pellets:  also called sleet.  These form when rain falls through air with temperatures below freezing.  Ice pellets do not produce structural icing unless mixed with super-cooled water (liquid water at temperatures below freezing).

        Hail:  a form of precipitation composed of irregular lumbs of ice that develop in severe thunderstorms.  It does not lead to the formation of structural ice, but it can cause structural damage to the aircraft.

        Snow:  destroys visibility.  This occurs at temperatures below freezing when water vapor changes directly into minute ice crystals.  Dry sow does not lead to the formation of structural ice, but wet snow does.

        Wet Snow:  Sow in its true state forms as the result of deposition in the upper limits of clouds.  Wet snow occurs at temperatures just below freezing.  Snow falling through supercooled water absorbs some of the moisture creating an icing hazard.  The pilot now has two options:  1)  The pilot can climb to the colder temperatures util encountering dry snowflakes; no hazard.  2)  The pilot can descent to an altitude where the air temperatures are well above freezing.

        Structural icing:

        There are three requirements for the formation of structural icing:
        1)  outside air temperature below freezing
        2)  aircraft skin temperature below freezing
        3)  visible moisture

        There are three factors that affect the rate of ice accumulation:
        1)  the size and number of water drops in a given volume of air (small
            waterdrops should be deflected easily)
        2)  airfoil thickness
        3)  airspeed (the faster you are going the more you are going to
            accumulate)

        Types of ice:

        Clear ice:  occurs in cumuliform clouds with appropriate temperatures (0 C to -10 C) where vertical currents can support large drops.  Clear ice can form rapidly on aircraft while flying in areas of freezing rain or drizzle.

        Rime ice:  no as dangerous as clear ice.  Rime can be expected in stratiform clouds since vertical currents are not strong enough to support large droplets.  Formed through the rapid freezing of small supercooled water droplets.  Most likely to occur at temps between -10 to -20 C.

        Frost:  a thin layer of crystalline ice that forms on exposed surfaces when the temperature of the exposed surface is below freezing and the dew point is below freezing.  Frost forms when both the temperature and dew point are below freezing and they are within about 5 degrees F of each other, the nigh skies are clear, and the winds are calm.  If a parked aircraft’s skin temperature drops below freezing, as the result of radiational cooling, and equals the dew point temperature, water vapor deposits on the aircraft as frost.
        Frost, like rime ice and clear ice, increases drag, causes a loss of lift, and therefore, must be removed prior to takeoff.  It is especially a hazard to takeoff as it increases your stall speed.

        Anti-icing and deicing equipment:

        1)  Mechanical boots are rubber bladders installed on the leading edges of lift producing surfaces.  They expand and crack up ice.
        2)  Fluids are freezing point depressants.  Ground crews will rinse the T-34C off prior to takeoff if necessary.
        3)  Heat application to pitot tube is about all the T-34 has.

        Icing detection:

        1)  Ice on windshield wiper arms or projections such as engine drain
            tubes pitot tubes, engine inlet lips, or propeller spinner.
        2)  Decreasing airspeed with constant power and altitude.
        3)  Ice detector annunciation (unfortunately the T-34 doesn’t have one
            of these).

        Other types of icing:

        1)  Induction icing.  The reduced pressure which exists at the intake lowers the temperature to the point that condensation and/or deposition take place, resulting in the formation of ice.

        2)  Compressor icing.  Ice forming on compressor inlet screens and compressor inlet guide vanes will restrict the flow of inlet air.  The T-34’s inertial separator should vector heavy moisture particles out of the system.  If not, it’ll cause the fuel-air ration to increase as air-flow decreases, which in turn raises the temperature of the gases going to the turbine.  The fuel control attempts to correct any loss in engine RPM by adding more fuel, which aggravates the condition.

        3)  Fuel system icing.  Under conditions of cold outside temperature (i.e., high altitude), an engine flameout may result from frozen fuel lines.

        Flight techniques:

        1)  Do not fly parallel to a front while encountering icing conditions.
        2)  Avoid the area below 4000 or 5000 feet above ridges when flying on instruments through clouds at indicated free air temps less than 0 deg C.
        3)  Do not make steep turns with ice on the airplane due to increased stall speeds.
        4)  Do not land with reduced power, use higher airspeeds when ice has formed on the wings and other exposed surfaces of the plane.
        5)  Avoid high AOA when ice has formed on the aircraft since stalling speeds have increased.
        6)  Do not forget when flying under icing conditions, that fuel consumption is greater, due to increased drag and the additional power required.
        7)  Avoid icing conditions as much as possible in the terminal phase of flight due to reduced airspeeds.
        8)  Always remove ice or frost from airfoils before attempting takeoff.

        Icing reporting criteria:

        1)  TRACE - rate of accumulation is slightly greater than sublimation

        2)  LIGHT - rate of accumulation may create a problem if flight is prolonged in this environment (over one hour).  It does not present a problem if deicing equipment is used.

        3)  MODERATE - the rate of accumulation is such that even short encounters become potentially hazardous and use of deicing/anti-icing equipment or diversion is necessary.

        4)  SEVERE - rate of accumulation is such that deicing/anti-icing equipment fails to reduce or control the hazard.  Immediate diversion is necessary.

        PIREPs include the following information:  aircraft id, location, time GMT, intensity, type, altitude, aircraft type, airspeed

    b.  Compressor stalls

        Compressor stalls may be characterized by an audible change in engine noise (a loud bang or backfire) with fluctuations in torque, ITT, N1, and fuel flow.  Additionally, flames and smoke may be visible from the engine exhaust stacks.  A severe compressor stall may result in engine damage and/or flameout.  Compressor stalls may be caused by damaged or degraded compressor or turbine blades, disrupted airflow, or compressor bleed valve malfunction.

        If compressor stalls occur, proceed as follows:
        1)  PCL - SLOWLY RETARD TO JUST BELOW STALL THRESHOLD TO CLEAR STALL
        2)  Cockpit environmental control - FULL FORWARD
        3)  PCL - SLOWLY ADJUST TO DESIRED POWER SETTING

WARNING - Avoid unnecessary PCL movement.  Advancing the PCL may result in further compressor stalls and engine flameout.  Retarding the PCL further may limit maximum power available.

        If sufficient power is available:
        4)  PEL - EXECUTE
 
        If sufficient power is insufficient to execute a PEL:
        5)  Proceed to the nearest suitable landing field and execute the
            ENGINE FAILURE procedure.

WARNING - Use of manual fuel control will only aggravate compressor stalls and could lead to flameout.

WARNING - When the engine is so underpowered that high rates of descent occur, any delay in feathering the propeller may result in insufficient altitude to reach a suitable landing site.

NOTE - If the situation permits, record the altimeter, OAT, max ITT, and duration of compressor stall.

NOTE - If resultant power is sufficient to maintain a rate of descent less than the feathered condition (600-800 fpm clean), consideration should be given to allowing the engine to operate until the field is made.

    b.  Uncontrollable high power

        The bearings or shaft in the FCU could fail without prior fluctuations, causing fuel flow to go to maximum, resulting in a very high-power condition that will be unresponsive to PCL movements.  If torque, N1, and fuel flow go to maximum and the engine is unresponsive to PCL movements, proceed as follows:
        1)  PEL - EXECUTE (climb or accelerate to a suitable paved field).

WARNING - Certain failures can cause wide power surges from maximum to as low as minimum fuel flow.  Engagement of the EPL in this case will have no effect on the high end of the power fluctuations, but may raise the low end of the surges, thus reducing the magnitude of the fluctuations.

        2)  Friction lock knob - FULL DECREASE

        3)  Condition lever - RAPIDLY RETARD TO FUEL OFF

CAUTION - When retarding the condition lever, do not hesitate in the FEATHER detent because high power from the engine with the propeller in FEATHER may cause sever airframe vibration and very high torque applied to the propeller and reduction gearbox.

NOTE - Altitude permitting, the pilot may elect to shutdown the engine with the emergency fuel shutoff handle.  The engine may continue running for as long as 30 seconds after the handle is pulled.

        4)  Execute ENGINE FAILURE procedures.
 
 
 
 
 

    c.  Any emergency procedure

2.  Review:

    a.  ICA
    b.  GCA maneuver
    c.  Approach pattern
    d.  S-1 pattern
    e.  Partial panel
    f.  Penetration maneuver
    g.  BAC maneuver
    h.  Direct to VOR or TACAN

3.  Non-graded:
 
    a.  UA-FP/PP