Emergency Procedures for the CESSNA 172M SKYHAWK

(4) Land the airplane as soon as possible to inspect for damage. WING FIRE (1) Navigation Light Switch (2) Pitot Heat Switch (if installed). 11 OFF. -- OFF. NOTE Perform a sideslip to keep the flames away from the fuel tank and cabin, and land as soon as possible using flaps only as required for final approach and touchdown. (4) Cabin Heat and Air OFF (except overhead vents). (5) Airspeed -- 100 KIAS (If fire is not extinguished, increase glide speed to find an airspeed which will provide an incombustible mixture). (6) Forced Landing EXECUTE (as described in Emergency Land- ing Without Engine Power). ELECTRICAL FIRE IN FLIGHT (1) Master Switch -- OFF. (2) All Other Switches (except ignition switch) (3) Vents/Cabin Air/Heat -- CLOSED. (6) -- OFF. (01) (4) Fire Extinguisher ACTIVATE (if available). If fire appears out and electrical power is necessary for continuance of flight: (5) Master Switch -- ON. (6) Circuit Breakers -- -- CHECK for faulty circuit, do not reset. ON one at a time, with delay after OPEN when it is ascertained that fire (7) Radio/Electrical Switches each until short circuit is localized. (8) Vents/Cabin Air/Heat is completely extinguished. CABIN FIRE (1) Master Switch -- OFF. (2) Vents/Cabin Air/Heat (3) Fire Extinguisher CLOSED (to avoid drafts). ACTIVATE (if available). WARNING After discharging an extinguisher within a closed cabin, ventilate the cabin. ICING INADVERTENT ICING ENCOUNTER (1) Turn pitot heat switch ON (if installed). (2) Turn back or change altitude to obtain an outside air temperature that is less conducive to icing. (3) Pull cabin heat control full out and open defroster outlet to obtain maximum windshield defroster airflow. Adjust cabin air control to get maximum defroster heat and airflow. (4) Open the throttle to increase engine speed and minimize ice build-up on propeller blades. (5) Watch for signs of carburetor air filter ice and apply carburetor heat as required. An unexplained loss in engine speed could be caused by carburetor ice or air intake filter ice. Lean the mixture for maxi- mum RPM if carburetor heat is used continuously. (6) Plan a landing at the nearest airport. With an extremely rapid ice build-up, select a suitable "off airport" landing site. (7) With an ice accumulation of 1/4 inch or more on the wing leading edges, be prepared for significantly higher stall speed. (8) Leave wing flaps retracted. With a severe ice build-up on the horizontal tail, the change in wing wake airflow direction caused by wing flap extension could result in a loss of elevator effectiveness. (9) Open left window and, if practical, scrape ice from a portion of the windshield for visibility in the landing approach. (10) Perform a landing approach using a forward slip, if necessary, for improved visibility. (11) Approach at 65 to 75 KIAS, depending upon the amount of the accumulation. (12) Perform a landing in level attitude. 3-6 3-7 SECTION 3 EMERGENCY PROCEDURES CESSNA MODEL 172M CESSNA MODEL 172M SECTION 3 EMERGENCY PROCEDURES AMPLIFIED PROCEDURES STATIC SOURCE BLOCKAGE (Erroneous Instrument Reading Suspected) -- (1) Alternate Static Source Valve PULL ON. (2) Airspeed Consult appropriate calibration tables in Section 5. -8 LANDING WITH A FLAT MAIN TIRE (1) Approach (2) Touchdown long as possible. -- NORMAL. GOOD TIRE FIRST, hold airplane off flat tire as ELECTRICAL POWER SUPPLY SYSTEM MALFUNCTIONS OVER-VOLTAGE LIGHT ILLUMINATES (1) Master Switch OFF (both sides). (2) Master Switch 13 ON. -- OFF. (3) Over-Voltage Light. If over-voltage light illuminates again: (4) Flight TERMINATE as soon as possible. AMMETER SHOWS DISCHARGE (1) Alternator -- OFF. (2) Nonessentail Electrical Equipment -- OFF. (3) Flight TERMINATE as soon as practical. ENGINE FAILURE If an engine failure occurs during the takeoff run, the most important thing to do is stop the airplane on the remaining runway. Those extra items on the checklist will provide added safety during a failure of this type. Prompt lowering of the nose to maintain airspeed and establish a glide attitude is the first response to an engine failure after takeoff. In most cases, the landing should be planned straight ahead with only small changes in direction to avoid obstructions. Altitude and airspeed are sel- dom sufficient to execute a 180° gliding turn necessary to return to the runway. The checklist procedures assume that adequate time exists to secure the fuel and ignition systems prior to touchdown. After an engine failure in flight, the best glide speed as shown in Fig- ure 3-1 should be established as quickly as possible. While gliding to- ward a suitable landing area, an effort should be made to identify the cause of the failure. If time permits, an engine restart should be attempted as shown in the checklist. If the engine cannot be restarted, a forced landing without power must be completed. HEIGHT ABOVE TERRAIN - FT 12,000 10,000 8000 6000 4000 2000 0 0 2 4 * SPEED 65 KIAS * PROPELLER WINDMILLING * FLAPS UP ZERO WIND 14 16 18 6 8 10 12 GROUND DISTANCE - NAUTICAL MILES 20 20 3-8 Figure 3-1. Maximum Glide 3-9 SECTION 3 EMERGENCY PROCEDURES FORCED LANDINGS CESSNA MODEL 172M If all attempts to restart the engine fail and a forced landing is immi- nent, select a suitable field and prepare for the landing as discussed in the checklist for engine off emergency landings. Before attempting an "off airport" landing with engine power avail- able, one should drag the landing area at a safe but low altitude to inspect the terrain for obstructions and surface conditions, proceeding as dis- cussed under the Precautionary Landing With Engine Power checklist. Prepare for ditching by securing or jettisoning heavy objects located in the baggage area and collect folded coats or cushions for protection of occupants' face at touchdown. Transmit Mayday message on 121.5 MHz giving location and intentions. Avoid a landing flare because of difficulty in judging height over a water surface. LANDING WITHOUT ELEVATOR CONTROL. Trim for horizontal flight (with an airspeed of approximately 60 KIAS and flaps set to 20°) by using throttle and elevator trim control. Then do not change the elevator trim control setting; control the glide angle by adjusting power exclusively. At flareout the nose-down moment resulting from power reduction is an adverse factor and the airplane may hit on the nose wheel. Conse- quently, at flareout, the elevator trim control should be adjusted toward the full nose-up position and the power adjusted so that the airplane will rotate to the horizontal attitude for touchdown. Close the throttle at touch- down. FIRES Although engine fires are extremely rare in flight, the steps of the appropriate checklist should be followed if one is encountered. After completion of this procedure, execute a forced landing. The initial indication of an electrical fire is usually the odor of burn- ing insulation. The checklist for this problem should result in elimination of the fire. CESSNA MODEL 172M. SECTION 3 EMERGENCY PROCEDURES EMERGENCY OPERATION IN CLOUDS (Vacuum System Failure) In the event of a vacuum system failure during flight in marginal weather, the directional indicator and attitude indicator will be disabled, and the pilot will have to rely on the turn coordinator or the turn and bank indicator if he inadvertently flies into clouds. The following instructions assume that only the electrically-powered turn coordinator or the turn and bank indicator is operative, and that the pilot is not completely pro- ficient in instrument flying. EXECUTING A 180° TURN IN CLOUDS Upon inadvertently entering the clouds, an immediate plan should be made to turn back as follows: (1) Note the time of the minute hand and observe the position of the sweep second hand on the clock. (2) When the sweep second hand indicates the nearest half-minute, initiate a standard rate left turn, holding the turn coordinator sym- bolic airplane wing opposite the lower left index mark for 60 seconds. Then roll back to level flight by leveling the miniature airplane. (3) Check accuracy of the turn by observing the compass heading which should be the reciprocal of the original heading. (4) If necessary, adjust heading primarily with skidding motions rather than rolling motions so that the compass will read more ac- curately. (5) Maintain altitude and airspeed by cautious application of elevator control. Avoid overcontrolling by keeping the hands off the control wheel and steering only with rudder. EMERGENCY DESCENT THROUGH CLOUDS If conditions preclude reestablishment of VFR flight by a 180° turn, a descent through a cloud deck to VFR conditions may be appropriate. If possible, obtain radio clearance for an emergency descent through clouds. To guard against a spiral dive, choose an easterly or westerly heading to minimize compass card swings due to changing bank angles. In addition, keep hands off the control wheel and steer a straight course with rudder control by monitoring the turn coordinator. Occasionally check the com- pass heading and make minor corrections to hold an approximate course. Before descending into the clouds, set up a stabilized let-down condition as follows: (1) Apply full rich mixture. (2) Use full carburetor heat. 3-10 3-11 SECTION 3 EMERGENCY PROCEDURES CESSNA MODEL 172M (3) Reduce power to set up a 500 to 800 ft/min rate of descent. (4) Adjust the elevator trim for a stabilized descent at 70-80 KIAS. (5) Keep hands off the control wheel. (6) Monitor turn coordinator and make corrections by rudder alone. (7) Check trend of compass card movement and make cautious cor- rections with rudder to stop the turn. (8) Upon breaking out of clouds, resume normal cruising flight. RECOVERY FROM A SPIRAL DIVE If a spiral is encountered, proceed as follows: (1) Close the throttle. (2) Stop the turn by using coordinated aileron and rudder control to align the symbolic airplane in the turn coordinator with the horizon reference line. (3) Cautiously apply elevator back pressure to slowly reduce the airspeed to 80 KIAS. (4) Adjust the elevator trim control to maintain an 80 KIAS glide. (5) Keep hands off the control wheel, using rudder control to hold a straight heading. (6) Apply carburetor heat. (7) Clear engine occasionally, but avoid using enough power to dis- turb the trimmed glide. (8) Upon breaking out of clouds, resume normal cruising flight. FLIGHT IN ICING CONDITIONS Flight into icing conditions is prohibited. An inadvertent encounter with these conditions can best be handled using the checklist procedures. The best procedure, of course, is to turn back or change altitude to es- cape icing conditions. STATIC SOURCE BLOCKED If erroneous readings of the static source instruments (airspeed, altimeter and rate-of-climb) are suspected, the alternate static source valve should be pulled on, thereby supplying static pressure to these instruments from the cabin. NOTE In an emergency on airplanes not equipped with an alter- nate static source, cabin pressure can be supplied to the static pressure instruments by breaking the glass in the face of the rate-of-climb indicator. CESSNA MODEL 172M SECTION 3 EMERGENCY PROCEDURES With the alternate static source on, adjust indicated airspeed slightly during climb or approach according to the alternate static source airspeed calibration table in Section 5, appropriate to vent/window(s) configuration, causing the airplane to be flown at the normal operating speeds. Maximum airspeed and altimeter variation from normal is 4 knots and 30 feet over the normal operating range with the window(s) closed. With window(s) open, larger variations occur near stall speed. However, maxi- mum altimeter variation remains within 50 feet of normal. SPINS Should an inadvertent spin occur, the following recovery procedure should be used: (1) RETARD THROTTLE TO IDLE POSITION. (2) PLACE AILERONS IN NEUTRAL POSITION. (3) APPLY AND HOLD FULL RUDDER OPPOSITE TO THE DIREC- TION OF ROTATION. (4) JUST AFTER THE RUDDER REACHES THE STOP, MOVE THE CONTROL WHEEL BRISKLY FORWARD FAR ENOUGH TO BREAK THE STALL. Full down elevator may be required at aft center of gravity loadings to assure optimum recoveries. (5) HOLD THESE CONTROL INPUTS UNTIL ROTATION STOPS. Premature relaxation of the control inputs may extend the recovery. (6) AS ROTATION STOPS, NEUTRALIZE RUDDER, AND MAKE A SMOOTH RECOVERY FROM THE RESULTING DIVE. NOTE If disorientation precludes a visual determination of the direction of rotation, the symbolic airplane in the turn coordinator or the needle of the turn and bank indicator may be referred to for this information. For additional information on spins and spin recovery, see the discussion under SPINS in Normal Procedures (Section 4). ROUGH ENGINE OPERATION OR LOSS OF POWER CARBURETOR ICING A gradual loss of RPM and eventual engine roughness may result from 3-12 3-13 SECTION 3 EMERGENCY PROCEDURES CESSNA MODEL 172M the formation of carburetor ice. To clear the ice, apply full throttle and pull the carburetor heat knob full out until the engine runs smoothly; then remove carburetor heat and readjust the throttle. If conditions require the continued use of carburetor heat in cruise flight, use the minimum amount of heat necessary to prevent ice from forming and lean the mix- ture for smoothest engine operation. SPARK PLUG FOULING A slight engine roughness in flight may be caused by one or more spark plugs becoming fouled by carbon or lead deposits. This may be verified by turning the ignition switch momentarily from BOTH to either L or R position. An obvious power loss in single ignition operation is evidence of spark plug or magneto trouble. Assuming that spark plugs are the more likely cause, lean the mixture to the recommended lean set- ting for cruising flight. If the problem does not clear up in several min- utes, determine if a richer mixture setting will produce smoother opera- tion. If not, proceed to the nearest airport for repairs using the BOTH position of the ignition switch unless extreme roughness dictates the use of a single ignition position. MAGNETO MALFUNCTION A sudden engine roughness or misfiring is usually evidence of mag- neto problems. Switching from BOTH to either L or R ignition switch position will identify which magneto is malfunctioning. Select different power settings and enrichen the mixture to determine if continued opera- tion on BOTH magnetos is practicable. If not, switch to the good magneto and proceed to the nearest airport for repairs. LOW OIL PRESSURE If low oil pressure is accompanied by normal oil temperature, there is a possibility the oil pressure gage or relief valve is malfunctioning. A leak in the line to the gage is not necessarily cause for an immediate pre- cautionary landing because an orifice in this line will prevent a sudden loss of oil from the engine sump. However, a landing at the nearest air- port would be advisable to inspect the source of trouble. If a total loss of oil pressure is accompanied by a rise in oil temper- ature, there is good reason to suspect an engine failure is imminent. Re- duce engine power immediately and select a suitable forced landing field. Use only the minimum power required to reach the desired touchdown spot. 3-14 CESSNA MODEL 172M SECTION 3 EMERGENCY PROCEDURES ELECTRICAL POWER SUPPLY SYSTEM MALFUNCTIONS Malfunctions in the electrical power supply system can be detected by periodic monitoring of the ammeter and over-voltage warning light; how- ever, the cause of these malfunctions is usually difficult to determine. A broken alternator drive belt or wiring is most likely the cause of alterna- tor failures, although other factors could cause the problem. A damaged or improperly adjusted voltage regulator can also cause malfunctions. Problems of this nature constitute an electrical emergency and should be dealt with immediately. Electrical power malfunctions usually fall into two categories: excessive rate of charge and insufficient rate of charge. The following paragraphs describe the recommended remedy for each situation. EXCESSIVE RATE OF CHARGE After engine starting and heavy electrical usage at low engine speeds (such as extended taxiing) the battery condition will be low enough to ac- cept above normal charging during the initial part of a flight. However, after thirty minutes of cruising flight, the ammeter should be indicating less than two needle widths of charging current. If the charging rate were to remain above this value on a long flight, the battery would overheat and evaporate the electrolyte at an excessive rate. Electronic components in the electrical system could be adversely affected by higher than normal voltage if a faulty voltage regulator setting is causing the overcharging. To preclude these possibilities, an over-voltage sensor will automatically shut down the alternator and the over-voltage warning light will illuminate if the charge voltage reaches approximately 16 volts. Assuming that the malfunction was only momentary, an attempt should be made to reactivate the alternator system. To do this, turn both sides of the master switch off and then on again. If the problem no longer exists, normal alternator charging will resume and the warning light will go off. If the light comes on again, a malfunction is confirmed. In this event, the flight should be terminated and/or the current drain on the battery minimized because the battery can supply the electrical system for only a limited period of time. If the emergency occurs at night, power must be conserved for later use of landing lights and flaps during landing. INSUFFICIENT RATE OF CHARGE If the ammeter indicates a continuous discharge rate in flight, the alternator is not supplying power to the system and should be shut down since the alternator field circuit may be placing an unnecessary load on the system. All nonessential equipment should be turned off and the flight terminated as soon as practical. 3-15/(3-16 blank)