The following is a list of equipment need to park and/or moor (tie down) the airplane.
• 4 wheel chocks
• 3 screw-in mooring rings (left and right wing, and tail)
• 3 ropes (nylon or other non-shrinking/non-stretching synthetic material)
If wheel brakes are hot from prolonged taxi, allow brakes to cool before setting parking
Controls may be secured with ailerons neutral and horizontal stabilizers leading edge
down by pulling the control stick aft as far as possible and fastening seat belt snugly
Perform this procedure for short-term parking of the airplane.
1. Taxi or tow airplane to desired parking position.
2. Align nose of airplane into the wind.
3. Ensure nose wheel is centered.
4. In windy or gusty weather, moor (tie down) the airplane, see Section 10-20
Mooring (Tying Down) on page 11 of this chapter.
5. Set the parking brake.
If wheel brakes are hot from prolonged taxi, allow brakes to cool before setting parking
6. Place chocks in front of and behind main wheels.
7. Release the parking brake.
8. Secure flight controls in neutral position; retract flaps.
Controls may be secured with ailerons neutral and horizontal stabilizers leading edge
down by pulling the control stick aft as far as possible and fastening seat belt snugly
9. Close and lock the doors.
Perform this procedure for long-term parking of the airplane.
1. Perform the steps for short-term: parking.
2. Moor (tie down) the airplane, see Section 10-20 Mooring (Tying Down) on
page 11 of this chapter..
3. Install external rudder lock if available.
ALL GUST LOCKS MUST BE REMOVED FROM THE AIRCRAFT PRIOR TO TAXI AND FLIGHT. CARE
SHOULD BE TAKEN NOT TO DEFORM OR DAMAGE THE STRUCTURE DURING INSTALLATION AND
REMOVAL OF THESE LOCKS. ALL DEFOMRATION, DAMAGE AND INTERFERENCE MUST BE
REVIEWED BY A QUALIFIED MECHANIC OR TECHNICIAN PRIOR TO FLIGHT.
4. Install pitot/static, canopy, and propeller covers as applicable.
5. Refer to engine, electrical, and fuel system chapters of this manual for information on required servicing for long-term storage.
The airplane has three mooring points: one under each wing, and one under the tail. Mooring rings are provided to secure tie down ropes into the mooring points. Park the airplane, see the procedures for short and long term parking of the airplane.
Attach tie-down ropes to ground tie-downs and aircraft mooring rings. Leave sufficient play or looseness in the ropes to prevent inadvertent loading of the structure. Also, if using a rope, tie a bowline knot to allow tension freedom.
The aviation technician must be familiar with the jacking of aircraft in order to perform maintenance and inspection. Since jacking procedures and safety precautions vary for different types of aircraft, only general jacking procedures and precautions are discussed. Consult the applicable aircraft manufacturer’s maintenance instructions for specific jacking procedures.
Extensive aircraft damage and serious personal injury have resulted from careless or improper jacking procedures. As an added safety measure, jacks should be inspected before use to determine the specific lifting capacity, proper functioning of safety locks, condition of pins, and general serviceability. Before raising an aircraft on jacks, all work stands and other equipment should be removed from under and near the aircraft. No one should remain in the aircraft while it is being raised or lowered, unless maintenance manual procedures require such practice for observing levelling instruments in the aircraft.
The aircraft to be jacked must be located in a level position, well protected from the wind. A hangar should be used if possible. The manufacturer’s maintenance instructions for the aircraft being jacked should be consulted for the location of the jacking points. These jacking points are usually located in relation to the aircraft center of gravity so the aircraft will be well balanced on the jacks. However, there are some exceptions to this. On some aircraft it may be necessary to add weight to the nose or tail of the aircraft to achieve a safe balance. Sandbags are usually used for this purpose.
Tripod jacks similar to the one shown in figure 11-38 are used when the complete aircraft is to be jacked.
A small single base jack similar to the one shown in figure 11-39 is used when only one wheel is to be raised. The jacks used for jacking aircraft must be maintained in good condition; a leaking or damaged jack must never be used. Also, each jack has a maximum capacity, which must never be exceeded.
Jacking Complete Aircraft
Prior to jacking the aircraft, an overall survey of the complete situation should be made to determine if any hazards to the aircraft or personnel exist. Tripod jacks of the appropriate size for the aircraft being jacked should be placed under the aircraft jacking points and perfectly centered to prevent them from cocking when the aircraft is raised. The legs of the jacks should be checked to see that they will not interfere with the operations to be performed after the aircraft is jacked, such as retracting the landing gear.
At least three places or points are provided on aircraft for jacking purposes; a fourth place on some aircraft is used to stabilize the aircraft while it is being jacked at the other three points. The two main places are on the wings, with a smaller one on the fuselage near either the tail or the nose, depending on the landing gear design.
Most aircraft have jack pads located at the jack points. Others have removable jack pads that are inserted into receptacles bolted in place prior to jacking. The correct jack pad should be used in all cases. The function of the jack pad is to ensure that the aircraft load is properly distributed at the jack point and to provide a convex bearing surface to mate with the concave jack stem. Figure 11-40 illustrates two types of jack pads.
Prior to jacking, determine if the aircraft configuration will permit jacking. There may be equipment or fuel which has to be removed if serious structural damage is to be avoided during jacking. If any other work is in progress on the aircraft, ascertain if any critical panels have been removed. On some aircraft the stress panels or plates must be in place when the aircraft is jacked to avoid structural damage.
Extend the jacks until they contact the jack pads. A final check for alignment of the jacks should be made before the aircraft is raised, since most accidents during jacking are the result of misaligned jacks.
When the aircraft is ready to be raised, a man should be stationed at each jack. The jacks should be operated simultaneously to keep the aircraft as level as possible and to avoid overloading any of the jacks. This can be accomplished by having the crew leader stand in front of the aircraft and give instructions to the men operating the jacks. Figure 11-41 shows an aircraft being jacked.
Caution should be observed, since on many jacks the piston can be raised beyond the safety point; therefore, never raise an aircraft any higher than is necessary to accomplish the job.
The area around the aircraft should be secured while the aircraft is on jacks. Climbing on the aircraft should be held to an absolute minimum, and no violent movements should be made by persons who are required to go aboard. Any cradles or necessary supports should be placed under the fuselage or wings of the aircraft at the earliest possible time, particularly if the aircraft is to remain jacked for any length of time.
On collet equipped jacks, the collet should be kept within two threads of the lift tube cylinder during raising, and screwed down firmly to the cylinder after jacking is completed to prevent settling.
Before releasing jack pressure and lowering the aircraft, make certain that all cribbing, work stands, equipment, and persons are clear of the aircraft, that the landing gear is down and locked, and that all ground locking devices are properly installed.
Jacking One Wheel of an Aircraft
When only one wheel has to be raised to change a tire or to grease wheel bearings, a low single base jack is used. Before the wheel is raised, the remaining wheels must be chocked fore and aft to prevent movement of the aircraft. If the aircraft is equipped with a tail wheel, it must be locked. The wheel should be raised only high enough to clear the concrete surface. Figure 11-42 shows a wheel being raised using a single base jack.
On aircraft with a nose-wheel landing gear, a steering arm should be fitted to the nose wheel to guide the aircraft Light aircraft can be moved and guided, by hand or by a tug.
Special attention should be paid to the following:
Force should not be applied to the thin trailing or rear edges of wings or control surfaces such as ailerons or elevators.
Generally speaking it is better to push an aircraft backwards rather than forwards, because the leading edges of the wings and tail-plane are stronger than the trailing edges.
The struts, which support the undercarriage on some aircraft, are suitable for pushing the aircraft as these are the strength parts of the aircraft.
The flat of the hands should be used when pushing, so as to spread the load over the largest area.
When pushing on struts, the force should be applied as near to the end fittings as possible.
A propeller must never be used to push or pull the aircraft, as the engine should always be regarded as ‘live’ and a propeller may kick if it is turned.
On aircraft with a steering nose wheel connected to the rudder pedals, care must be taken not to exceed the turning limits. Normally the maximum limits are marked on nose wheel doors as “NO TOW”
On this type of aircraft it is also important that the rudder controls are not locked during the towing operations. This is because the rudder controls and the nose-wheel steering mechanism are interconnected and the excessive movements could damage the mechanical linkages.
When towing aircraft by tow bar and tug special care should be given to below facts,
The correct tow-bar should be connected between the towing attachment at the base of the nose undercarriage leg and the tug.
A person familiar with the aircraft brake system should be seated in the cockpit/cabin to operate the brakes in an emergency. The brakes should not normally be applied unless the aircraft is stationary.
Once the tow-bar is connected, the brakes, and if fitted, the rudder lock, may be released and the aircraft towed at a safe speed. A safe speed is considered to be walking speed.
In circumstances where the ground over which the aircraft has to be towed is either boggy or very uneven, the strain imposed on the nose undercarriage may be excessive and it may be necessary to tow the aircraft by means of bridles attached to each main undercarriage. If towing attachments are not provided on the main undercarriage legs, ropes should be passed carefully around the legs as near to the top as possible and avoiding fouling on adjacent pipes or structure. A separate tug should be connected to each main undercarriage assembly. Steering should be carried out by means of a steering arm attached to the nose wheel rather than by differential movement of the tugs.
The most common means of towing a large aircraft nowadays is by means of a tow bar-less aircraft handling tractor.These tractors tend to be front wheel driven and therefore when towing an aircraft, are acting to ‘pull’ the tractor/aircraft combination.The tow-barless tractor consists of a low level tractor with a rear mounted cradle, comprising of a ‘scoop and gate’ assembly.
Owing to the tractor’s low height it can easily move-in under the aircraft’s fuselage to couple-up with the aircraft’s nose wheel. During operation the nose wheel is raised by about 20cms by the tractor and after the towing is completed the nose wheel is lowered and the nose wheel is released from the cradle.
Engine Starting Procedures:
The following procedures are typical of those used to start reciprocating engines. There are, however, wide variations in the procedures for the many reciprocating engines. No attempt should be made to use the methods presented here for actually starting an engine. Instead, always refer to the procedures contained in the applicable manufacturer’s instructions.
Reciprocating engines are capable of starting in fairly low temperatures without the use of engine heating or oil dilution, depending on the grade of oil used.
The various covers (wing, tail, cockpit, wheel, etc.) protecting the aircraft must be removed before attempting to turn the engine. External sources of electrical power should be used when starting engines equipped with electric starters. This eliminates an excessive burden on the aircraft battery. All unnecessary electrical equipment should be left off until the generators are furnishing electrical power to the aircraft power bus.
Before starting a radial engine that has been shut down for more than 30 minutes, check the ignition switch for off; turn the propeller three or four complete revolutions with the starter, or it may be pulled through by hand to detect a hydraulic lock if one is present.
Any liquid present in a cylinder is indicated by the abnormal effort required to rotate the propeller, or by the propeller stopping abruptly during rotation. Never use force to turn the propeller when a hydraulic lock is detected.
Sufficient force can be exerted on the crankshaft to bend or break a connecting rod if a lock is present.
To eliminate a lock, remove either the front or rear spark plug from the lower cylinders and pull the propeller through. Never attempt to clear the hydraulic lock by pulling the propeller through in the opposite direction to normal rotation. This tends to inject the liquid from the cylinder into the intake pipe. The liquid will be drawn back into the cylinder with the possibility of complete or partial lock occurring on the subsequent start.
To start the engine, proceed as follows:
1. Turn the auxiliary fuel pump on, if aircraft is so equipped.
2. Place the mixture control to the position recommended for the engine and carburettor combination being started. As a general rule, the mixture control should be in the “idle cutoff” position for pressure type carburettors and in the “full rich” position for float type carburetors.
Many light aircraft are equipped with a mixture control pull rod which has no detented intermediate positions. When such controls are pushed in flush with the instrument panel, the mixture is set in the “full rich” position. Conversely, when the control rod is pulled all the way out, the carburetor is in the “idle cutoff” or “full lean” position. Unmarked intermediate positions between these two extremes can be selected by the operator to achieve any desired mixture setting.
3. Open the throttle to a position that will provide 1,000 to 1,200 rpm (approximately 1/8 to 1/2 inch from the “closed” position).
4. Leave the preheat or alternate air (carburetor air) control in the “cold” position to prevent damage and fire in case of backfire. These auxiliary heating devices should be used after the engine warms up. They improve fuel vaporization, prevent fouling of the spark plugs, ice formation, and eliminate icing in the induction system.
5. Energize the starter after the propeller has made at least two complete revolutions, and turn the ignition switch on. On engines equipped with an induction vibrator, turn switch to the “both” position. When starting an engine that uses an impulse coupling magneto, turn the ignition switch to the “left” position. Place the ignition switch to “start” when the magneto incorporates a retard breaker assembly. Do not crank the engine continuously with the starter for more than 1 minute. Allow a 3 to 5 minute period for cooling the starter between successive attempts. Otherwise the starter may be burned out due to overheating.
6. Move the primer switch to “on” intermittently, or prime with one to three strokes of priming pump, depending on how the aircraft is equipped. When the engine begins to fire, hold the primer on while gradually opening throttle to obtain smooth operation.
After the engine is operating smoothly on the primer, move the mixture control to the “full rich” position. Release the primer as soon as a drop in rpm indicates the engine is receiving additional fuel from the carburetor.
If the aircraft has no self starter, the engine must be started by swinging the propeller. The person who is turning the propeller calls, “fuel on, switch off, throttle closed, brakes on.” The person operating the engine will check these items and repeat the phrase. The switch and throttle must not be touched again until the person swinging the prop calls “contact.” The operator will repeat ” contact” and then turn on the switch. Never turn on the switch and then call “contact.”
When swinging the prop, a few simple precautions will help to avoid accidents. When touching a propeller, always assume that the ignition is on. The switches which control the magnetos operate on the principle of short circuiting the current to turn the ignition off. If the switch is faulty, it can be in the “off” position and still permit current to flow in the magneto primary circuit.
Be sure the ground is firm. Slippery grass, mud, grease, or loose gravel can lead to a fall into or under the propeller. Never allow any portion of your body to get in the way of the propeller. This applies even though the engine is not being cranked. Stand close enough to the propeller to be able to step away as it is pulled down. Stepping away after cranking is a safeguard in case the brakes fail.
Do not stand in a position that requires leaning toward the propeller to reach it. This throws the body off balance and could cause you to fall into the blades when the engine starts.
In swinging the prop, always move the blade downward by pushing with the palms of the hand. Do not grip the blade with the fingers curled over the edge, since “kickback” may break them or draw your body in the blade path.
Excessive throttle opening and intermittent priming after the engine has fired are the principal causes of backfiring during starting. Gradual opening of the throttle while priming continuously will reduce the initial “over rich” mixture to a smooth running, best power mixture as the engine picks up speed. An engine operating on an “over rich” mixture is sluggish but will not backfire.
When starting an engine using a priming pump, move the mixture control into “full rich” position, if not previously placed there, when the engine begins to fire. If the engine fails to start immediately, return the mixture control to “idle cutoff” position. Failure to do so will create an excessive amount of fuel in the carburetor air scoop, constituting a fire hazard.
Avoid priming the engine before it is turned over by the starter. This can result in fires, scored or scuffed cylinders and pistons, and, in some cases, engine failures due to hydraulic lock. If the engine is inadvertently flooded or over primed, turn the ignition switch off and move the throttle to the “full open” position. To rid the engine of the excess fuel, turn it over by hand or by the starter. If excessive force is needed to turn over the engine, stop immediately. Do not force rotation of the engine. If in doubt, remove the lower cylinder spark plugs. If very serious overloading has occurred, it may be necessary to remove the lower cylinder intake pipes. To reduce the likelihood of damage to the engine due to over priming on some medium and large aircraft, the engine blower drain valves should be checked frequently for fouling or sticking.
Immediately after the engine starts, check the oil pressure indicator. If oil pressure does not show within 30 seconds, stop the engine and determine the trouble. If oil pressure is indicated, adjust the throttle to the aircraft manufacturer’s specified rpm for engine warmup. Warmup rpm will usually be in the 1,000 to 1,300 rpm range.
Most aircraft reciprocating engines are air cooled and depend on the forward speed of the aircraft to maintain proper cooling. Therefore, particular care is necessary when operating these engines on the ground.
During all ground running, operate the engine with the propeller in full low pitch and headed into the wind with the cowling installed to provide the best degree of engine cooling. The engine instruments should be monitored closely at all times. Do not close the cowl flaps for engine warmup; closing of the cowl flaps may cause the ignition harness to overheat. When warming up the engine, make sure that personnel, ground installations, equipment that may be damaged, or other aircraft are not in the propeller wash.
Extinguishing Engine Fires
In all cases a fireguard should stand by with a CO2 fire extinguisher while the aircraft engine is being started. This is a necessary precaution against fire during the starting procedure. He should be familiar with the induction system of the engine so that in case of fire he can direct the CO2 into the air intake of the engine to extinguish it. A fire could also occur in the exhaust system of the engine from liquid fuel being ignited in the cylinder and expelled during the normal rotation of the engine. If an engine fire develops during the starting procedure, continue cranking to start the engine and blow out the fire. If the engine does not start and the fire continues to burn, discontinue the start attempt. The fireguard should extinguish the fire using the available equipment. The fireguard must observe all safety practices at all times while standing by during the starting procedure.
The various covers protecting the aircraft must be removed. Engine tailpipes should be carefully inspected for the presence of fuel or oil. A close visual inspection of all accessible parts of the engines and engine controls should be made, followed by an inspection of all nacelle areas to determine that all inspection and access plates are secured. Sumps should be checked for water. Air inlet areas should be inspected for general condition and foreign material. The compressor should be checked for free rotation, when the installation permits, by reaching in and turning the blades by hand.
The following procedures are typical of those used to start turboprop engines. There are, however, wide variations in the procedures applicable to the many turboprop engines, and no attempt should be made to use these procedures in the actual starting of a turboprop engine. These procedures are presented only as a general guide for familiarization with typical procedures and methods. For starting of all turboprop engines, refer to the detailed procedures contained in the applicable manufacturer’s instructions or their approved equivalent.
The first step in starting a turbine engine is to provide an adequate source of power for the starter. Where an air turbine starter is used, the starting air supply may be obtained from a gas turbine compressor (GTC), an external source, or an engine crossbleed operation. To start the first engine, use a GTC or low pressure, large volume tank. Start the remaining engine(s) using bleed air from the running engine.
While starting an engine, always observe the following:
1. Never energize the starter while the engine is rotating.
2. Do not move the power lever of any engine while it is being bled for crossbleed starting.
3. Do not perform a ground start if turbine inlet temperature is above that specified by the manufacturer.
4. Do not use bleed air from an engine that is accelerating.
To start an engine on the ground, perform the following operations:
1. Place the start selector switch to the desired engine and the start arming switch (if so equipped) to the “start” position.
2. Turn the aircraft boost pumps on.
3. Place the fuel and ignition switch on.
4. Position the low rpm switch in low or normal (high).
5. Make sure that the power lever is in the “start” position. If the propeller is not at the “start” position, difficulty may be encountered in making a start.
6. Depress the start switch and, if priming is necessary, depress the primer button.
7. Make sure the fuel pump parallel light comes on at, or above, 2,200 rpm and remains on up to 9,000 rpm.
8. Check the oil pressure and temperature. Maintain the power lever at the “start” position until the specified minimum oil temperature is reached.
9. Disconnect the ground power supply.
If any of the following conditions occur during the starting sequence, turn off the fuel and ignition switch, discontinue the start immediately, make an investigation and record the findings.
1. Turbine inlet temperature exceeds the specified maximum. Record the observed peak temperature.
2. Acceleration time from start of propeller rotation to stabilized rpm exceeds the specified time.
3. There is no oil pressure indication at 5,000 rpm for either the reduction gear or the power unit.
4. Torching (visible burning in the exhaust nozzle other than normal enrichment) or excessive smoke is observed during initial fire up.
5. The engine fails to ignite by 4,500 rpm or maximum motoring rpm (whichever is first), and rpm stagnates or begins to decay.
6. Abnormal vibration is noted or compressor surge occurs (indicated by backfiring).
7. There is fuel spewing from the nacelle drain, indicating that the drip valve did not close.
8. Fire warning bell rings. (This may be due to either an engine fire or failure of an anti-icing shutoff valve to close.)
Unlike reciprocating engine aircraft, the turbojet powered aircraft does not require a pre-flight run-up unless it is necessary to investigate a suspected malfunction. Before starting, all protective covers and air inlet duct covers should be removed. If possible, the aircraft should be headed into the wind to obtain better cooling, faster starting, and smoother engine performance. It is especially important that the aircraft be headed into the wind if the engine is to be trimmed.
The run-up area around the aircraft should be cleared of both personnel and loose equipment.
The turbojet engine intake and exhaust hazard areas are illustrated in figure 11-1. Care should also be taken to ensure that the run-up area is clear of all items such as nuts, bolts, rocks, rags, or other loose debris.
A great number of very serious accidents occur involving personnel in the vicinity of turbojet engine air inlets. Extreme caution should be exercised when starting turbojet aircraft.
The aircraft fuel sumps should be checked for water or ice, and the engine air inlet should be inspected for general condition and the presence of foreign objects. The forward compressor blades and the compressor inlet guide vanes should be visually inspected for nicks and other damage.
If possible, the compressor should be checked for free rotation by turning the compressor blades by hand.
All engine controls should be operated, and engine instruments and warning lights should be checked for proper operation.
Starting a Turbojet Engine
The following procedures are typical of those used to start many turbojet engines. There are, however, wide variations in the starting procedures used for turbojet engines, and no attempt should be made to use these procedures in the actual starting of an engine. These procedures are presented only as a general guide for familiarization with typical procedures and methods. In the starting of all turbojet engines, refer to the detailed procedures contained in the applicable manufacturer’s instructions or their approved equivalent.
Most turbojet engines can be started by either air turbine or combustion-type starters. Air turbine starters use compressed air from an external source. This source may be a ground cart unit or air bled from another engine on the aircraft that is in operation. Combustion starters are small gas turbine engines that obtain power from expanding gases generated in the starter’s combustion chamber. These hot gases are produced by the burning of fuel and air or, in some cases, a slow burning solid or liquid monopropellant specially compounded for such starter units.
Fuel is turned on either by moving the power lever to “idle” position or by opening a fuel shutoff valve. If an air turbine starter is used, the engine should start or “light up” within approximately 20 seconds after the fuel is turned on. This is an arbitrarily chosen time interval that, if exceeded, indicates a malfunction has occurred and the start should be discontinued. After the cause of the trouble has been removed, another start may be made. If a combustion starter is used, the 20 second interval need not be observed, since starter operation will discontinue automatically after a predetermined time interval. The following procedures are useful only as a general guide, and are included to show the sequence of events in starting a turbojet engine.
1. Move power lever to “off” position unless the engine is equipped with thrust reverser. If the engine is so equipped, place the power lever in the “idle” position.
2. Turn on electrical power to engine.
3. Turn fuel system shutoff switch to “fuel on” position.
4. Turn fuel boost pump switch on.
5. A fuel inlet pressure indicator reading of 5 psi ensures fuel is being delivered to engine fuel pump inlet.
6. Turn engine starter switch on; when engine begins to rotate, check for oil pressure rise.
7. Turn ignition switch on after engine begins to rotate.
8. Move throttle to idle (if engine is not equipped with thrust reverser).
9. Engine start (light up) is indicated by a rise in exhaust gas temperature.
10. After engine stabilizes at idle, ensure that none of the engine limits are exceeded.
11. Turn engine starter switch off after start.
12. Turn ignition switch off.
Unsatisfactory Turbojet Starts
1. Hot Starts.
A hot start occurs when the engine starts, but the exhaust gas temperature exceeds specified limits. This is usually caused by an excessively rich fuel/air mixture entering the combustion chamber. The fuel to the engine should be shut off immediately.
2. False or Hung Start.
False or hung starts occur when the engine starts normally but the rpm remains at some low value rather than increasing to the normal starting rpm. This is often the result of insufficient power to the starter, or the starter cutting off before the engine starts self-accelerating. In this case, the engine should be shut down.
3. Engine Will Not Start.
The engine will not start within the prescribed time limit. It can be caused by lack of fuel to the engine, insufficient or no electrical power, or malfunctions in the ignition system. If the engine fails to start within the prescribed time, it should be shut down.
In all cases of unsatisfactory starts the fuel and ignition should be turned off. Continue rotating the compressor for approximately 15 seconds to remove accumulated fuel from the engine. If unable to motor (rotate) the engine, allow a 30 second fuel draining period before attempting another start.