Figure 18-6. Emergency descent.
When the descent is established and stabilized during training and practice, the descent should be terminated. In airplanes with piston
engines, prolonged practice of emergency descents should be avoided to prevent excessive cooling of the engine cylinders.
In-Flight Fire
A fire in-flight demands immediate and decisive action. The pilot should be familiar with the procedures outlined to meet this
emergency contained in the AFM/POH for the particular airplane. For the purposes of this handbook, in-flight fires are classified as
in-flight engine fires, electrical fires, and cabin fires.
Engine Fire
An in-flight engine compartment fire is usually caused by a failure that allows a flammable substance, such as fuel, oil, or hydraulic
fluid, to come in contact with a hot surface. This may be caused by a mechanical failure of the engine itself, an engine-driven
accessory, a defective induction or exhaust system, or a broken line. Engine compartment fires may also result from maintenan ce
errors, such as improperly installed/fastened lines and/or fittings resulting in leaks.
Engine compartment fires can be indicated by smoke and/or flames coming from the engine cowling area. They can also be indicated
by discoloration, bubbling, and/or melting of the engine cowling skin in cases where flames and/or smoke are not visible to the pilot.
By the time a pilot becomes aware of an in-flight engine compartment fire, it usually is well developed. Unless the airplane
manufacturer directs otherwise in the AFM/POH, the first step on discovering a fire should be to shut off the fuel supply to the engine
by placing the mixture control in the idle cut off position and the fuel selector shutoff valve to the OFF position. The ignition switch
should be left ON in order to use up the fuel that remains in the fuel lines and components between the fuel selector/shutoff valve and
the engine. This procedure may starve the engine compartment of fuel and cause the fire to die naturally. If the flames are snuffed out,
no attempt should be made to restart the engine.
If the engine compartment fire is oil-fed, as evidenced by thick black smoke, as opposed to a fuel-fed fire, which produces bright
orange flames, the pilot should consider stopping the propeller rotation by feathering or other means, such as (with constant-speed
propellers) placing the pitch control lever to the minimum rpm position and raising the nose to reduce airspeed until the propeller
stops rotating. This procedure stops an engine-driven oil (or hydraulic) pump from continuing to pump the flammable fluid that is
feeding the fire.
Some light airplane emergency checklists direct the pilot to shut off the electrical master switch. However, the pilot should consider
that unless the fire is electrical in nature, or a crash landing is imminent, deactivating the electrical system prevents the use of panel
radios for transmitting distress messages and also causes air traffic control (ATC) to lose transponder returns.
Pilots of powerless single-engine airplanes are left with no choice but to make a forced landing. Pilots of twin-engine airplanes may
elect to continue the flight to the nearest airport. However, consideration should be given to the possibility that a wing could be
seriously impaired and lead to structural failure. Even a brief but intense fire could cause dangerous structural damage. In some cases,
the fire could continue to burn under the wing (or engine cowling in the case of a single- engine airplane) out of view of the pilot.
Engine compartment fires that appear to have been extinguished have been known to rekindle with changes in airflow pattern an d
airspeed.
The pilot should be familiar with the airplane’s emergency descent procedures. The pilot should also bear in mind the following:
⦁ The airplane may be severely structurally damaged to the point that its ability to remain under control could
be lost at any moment.
⦁ The airplane may still be on fire and susceptible to explosion.
⦁ The airplane is expendable and the only thing that matters is the safety of those on board.
Electrical Fires
The initial indication of an electrical fire is usually the distinct odor of burning insulation. Once an electrical fire is detected, the pilot
should attempt to identify the faulty circuit by checking circuit breakers, instruments, avionics, and lights. If the faulty circuit cannot
be readily detected and isolated, and flight conditions permit, the battery master switch and alternator/generator switches should be
turned off to remove the possible source of the fire. However, any materials that have been ignited may continue to burn.
If electrical power is absolutely essential for the flight, an attempt may be made to identify and isolate the faulty circuit by:
1. Turning the electrical master switch OFF.
2. Turning all individual electrical switches OFF.
3. Turning the master switch back ON.
4. Selecting electrical switches that were ON before the fire indication one at a time, permitting a short time
lap
se after each switch is turned on to check for signs of odor, smoke, or sparks.
This procedure, however, has the effect of recreating the original problem. The most prudent course of action is to land as soon as
possible.
Cabin Fire
Cabin fires generally result from one of three sources: (1) careless smoking on the part of the pilot and/or passengers; (2) electrical
system malfunctions; or (3) heating system malfunctions. A fire in the cabin presents the pilot with two immediate demands: attacking
the fire and getting the airplane safely on the ground as quickly as possible. A fire or smoke in the cabin should be controlled by
identifying and shutting down the faulty system. In many cases, smoke may be removed from the cabin by opening the cabin air vents.
This should be done only after the fire extinguisher (if available) is used. Then the cabin air control can be opened to purge the cabin
of both smoke and fumes. If smoke increases in intensity when the cabin air vents are opened, they should be immediately closed.
This indicates a possible fire in the heating system, nose compartment baggage area (if so equipped), or that the increase in airflow is
feeding the fire.
On pressurized airplanes, the pressurization air system removes smoke from the cabin; however, if the smoke is intense, it may be
necessary to either depressurize at altitude, if oxygen is available for all occupants, or execute an emergency descent.
In unpressurized single-engine and light twin-engine airplanes, the pilot can attempt to expel the smoke from the cabin by opening the
foul weather windows. These windows should be closed immediately if the fire becomes more intense. If the smoke is severe, th e
passengers and crew should use oxygen masks if available, and the pilot should initiate an immediate descent. The pilot should also
be aware that on some airplanes, lowering the landing gear and/or wing flaps can aggravate a cabin smoke problem.
Flight Control Malfunction/Failure
Total Flap Failure
The inability to extend the wing flaps necessitates a no-flap approach and landing. In light airplanes, a no-flap approach and landing
is not particularly difficult or dangerous. However, there are certain factors that should be considered in the execution of this
maneuver. A no-flap landing requires substantially more runway than normal. The increase in required landing distance could be as
much as 50 percent.
When flying in the traffic pattern with the wing flaps retracted, the airplane should be flown in a relatively nose-high attitude to
maintain altitude, as compared to flight with flaps extended. Losing altitude can be more of a problem without the benefit of the drag
normally provided by flaps. A wider, longer traffic pattern may be required in order to avoid the necessity of diving to lose altitude
and consequently building up excessive airspeed.
On final approach, a nose-high attitude can make it difficult to see the runway. This situation, if not anticipated, can result in serious
errors in judgment of height and distance. Approaching the runway in a relatively nose-high attitude can also cause the perception that
the airplane is close to a stall. This may cause the pilot to lower the nose abruptly and risk touching down on the nose-wheel.
With the flaps retracted and the power reduced for landing, the airplane is slightly less stable in the pitch and roll axes. Without flaps,
the airplane tends to float considerably during roundout. The pilot should avoid the temptation to force the airplane onto the runway
at an excessively high speed. Neither should the pilot flare excessively because without flaps, this might cause the tail to strike the
runway.
Asymmetric (Split) Flap
An asymmetric “split” flap situation is one in which one flap deploys or retracts while the other remains in position. The pr oblem is
indicated by a pronounced roll toward the wing with the least flap deflection when wing flaps are extended/retracted.
The roll encountered in a split flap situation is countered with opposite aileron. The yaw caused by the additional drag created by the
extended flap requires substantial opposite rudder resulting in a cross-control condition. Almost full aileron may be required to
maintain a wings-level attitude, especially at the reduced airspeed necessary for approach and landing. The pilot should not attempt to
land with a crosswind from the side of the deployed flap because the additional roll control required to counteract the crosswind may
not be available.
The approach to landing with a split flap condition should be flown at a higher than normal airspeed. The pilot should not risk an
asymmetric stall and subsequent loss of control by flaring excessively. Rather, the airplane should be flown onto the runway so that
the touchdown occurs at an airspeed consistent with a safe margin above flaps-up stall speed.
Loss of Elevator Control
In many airplanes, the elevator is controlled by two cables: a “down” cable and an “up” cable. Normally, a break or disconnect in
only one of these cables does not result in a total loss of elevator control. In most airplanes, a failed cable results in a partial loss of
pitch control. In the failure of the “up” elevator cable (the “down” elevator being intact and functional), the control yoke moves aft
easily but produces no response. Forward yoke movement, however, beyond the neutral position produces a nose-down attitude.
Conversely, a failure of the “down” elevator cable, forward movement of the control yoke produces no effect. The pilot, however, has
partial control of pitch attitude with aft movement.
When experiencing a loss of up-elevator control, the pilot can retain pitch control by:
⦁ Applying considerable nose-up trim
⦁ Pushing the control yoke forward to attain and maintain desired attitude
⦁ Increasing forward pressure to lower the nose and relaxing forward pressure to raise the nose
⦁ Releasing forward pressure to flare for landing
When experiencing a loss of down-elevator control, the pilot can retain pitch control by:
⦁ Applying considerable nose-down trim
⦁ Pulling the control yoke aft to attain and maintain attitude
⦁ Releasing back pressure to lower the nose and increasing back pressure to raise the nose
⦁ Increasing back pressure to flare for landing
Trim mechanisms can be useful in the event of an in-flight primary control failure. For example, if the linkage between the cabin and
the elevator fails in flight, leaving the elevator free to weathervane in the wind, the trim tab can be used to raise or lower the elevator
within limits. The trim tabs are not as effective as normal linkage control in conditions such as low airspeed, but they do have some
positive effect—usually enough to bring about a safe landing.
If an elevator becomes jammed, resulting in a total loss of elevator control movement, various combinations of power and flap
extension offer a limited amount of pitch control. A successful landing under these conditions, however, can be problematic.
Landing Gear Malfunction
Once the pilot has confirmed that the landing gear has in fact malfunctioned and that one or more gear legs refuses to respond to the
conventional or alternate methods of gear extension contained in the AFM/POH, a gear-up landing is considered inevitable. The pilot
should select an airport with crash and rescue facilities, if possible. The pilot should not hesitate to request that emergency equipment
is standing by.
When selecting a landing surface, the pilot should consider that a smooth, hard-surface runway usually causes less damage than a
rough, unimproved grass strip. A hard surface does, however, create sparks that can ignite fuel. If the airport is so equipped, the pilot
can request that the runway surface be foamed. The pilot should consider burning off excess fuel. This reduces landing speed and fire
potential.
If the landing gear malfunction is limited to one main landing gear leg, the pilot should consume as much fuel from that side of the
airplane as practicable, thereby reducing the weight of the wing on that side. The reduced weight makes it possible to delay the
unsupported wing from contacting the surface during the landing roll until the last possible moment. Reduced impact speeds result in
less damage.
If only one landing gear leg fails to extend, the pilot has the option of landing on the available gear legs or landing with all the gear
legs retracted. Landing on only one main gear usually causes the airplane to veer strongly in the direction of the faulty gear leg after
touchdown. If the landing runway is narrow and/or ditches and obstacles line the runway edge, maximum directional control after
touchdown is a necessity. In this situation, a landing with all three gear retracted may be the safest course of action.
If the pilot elects to land with one main gear retracted (and the other main gear and nose gear down and locked), the landing should
be made in a nose-high attitude with the wings level. As airspeed decays, the pilot should apply whatever aileron control is necessary
to keep the unsupported wing airborne as long as possible. [Figure 18-7] Once the wing contacts the surface, the pilot can anticipate
a strong yaw in that direction. The pilot should be prepared to use full opposite rudder and aggressive braking to maintain some
degree of directional control.
Figure 18-7. Landing with one main gear retracted.
When landing with a retracted nose-wheel (and the main gear extended and locked), the pilot should hold the nose off the ground
until almost full up-elevator has been applied. [Figure 18-8] The pilot should then release back pressure in such a manner that the
nose settles slowly to the surface. Applying and holding full up-elevator results in the nose abruptly dropping to the surface as
airspeed decays, possibly resulting in burrowing and/or additional damage. Brake pressure should not be applied during the landing
roll unless absolutely necessary to avoid a collision with obstacles.
Figure 18-8. Landing with nose-wheel retracted.
If the landing occurs with only the nose gear extended, the initial contact should be made on the aft fuselage structure with a nose-
high attitude. This procedure helps prevent porpoising and/or wheelbarrowing. The pilot should then allow the nose-wheel to
gradually touchdown, using nose-wheel steering as necessary for directional control.
System Malfunctions
Electrical System
The loss of electrical power can deprive the pilot of numerous critical systems, and therefore should not be taken lightly even in
day/visual flight rules (VFR) conditions. Most in-flight failures of the electrical system are located in the generator or alternator. Once
the generator or alternator system goes off line, the electrical source in a typical light airplane is a battery. If a warning light or
ammeter indicates the probability of an alternator or generator failure in an airplane with only one generating system, however, the
pilot may have very little time available from the battery.
The rating of the airplane battery provides a clue as to how long it may last. With batteries, the higher the amperage load, the faster
any available stored energy gets consumed. Thus, a 25-amp hour battery could produce 5 amps per hour for 5 hours, but if the load
were increased to 10 amps, it might last only 2 hours. A 40-amp load might discharge the battery fully in about 10 or 15 minutes.
Much depends on the battery condition at the time of the system failure. If the battery has been in service for a few years, its power
may be reduced substantially because of internal resistance. Or if the system failure was not detected immediately, much of the stored
energy may have already been used. It is essential, therefore, that the pilot immediately shed non-essential loads when the generating
source fails. [Figure 18-9] The pilot should then plan to land at the nearest suitable airport.
What constitutes an “emergency” load following a generating system failure cannot be predetermined because the actual
circumstances are always somewhat different —for example, whether the flight is VFR or instrument flight rules (IFR), conducted in
day or at night, in clouds or in the clear. Distance to nearest suitable airport can also be a factor.
The pilot should remember that the electrically-powered (or electrically-selected) landing gear and flaps do not function properly on
the power left in a partially-depleted battery. Landing gear and flap motors use power at rates much greater than most other types of
electrical equipment. The result of selecting these motors on a partially-depleted battery may well result in an immediate total loss of
electrical power.
Figure 18-9. Electrical load for light single.
If the pilot expects an imminent and complete in-flight loss of electrical power, the following steps should be taken:
⦁ Shed all but the most necessary electrically-driven equipment.
⦁ Understand that any loss of electrical power is critical in a small airplane—notify ATC of the situation
immediately. Request radar vectors for a landing at the nearest suitable airport.
⦁ If landing gear or flaps are electrically controlled or operated, plan the arrival well ahead of time. Expect to
ake a no-flap landing and anticipate a manual landing gear extension.
Pitot-Static System
The source of the pressure for operating the airspeed indicator, the vertical speed indicator (VSI), and the altimeter is the pitot-static
system. The major components of the pitot-static system are the impact pressure chamber and lines and the static pressure chamber
and lines, each of which are subject to total or partial blockage by ice, dirt, and/or other foreign matter. Blockage of the pitot-static
system adversely affects instrument operation. [Figure 18-10]
Partial static system blockage is insidious in that it may go unrecognized until a critical phase of flight. During takeoff, climb, and
level-off at cruise altitude the altimeter, airspeed indicator, and VSI may operate normally. No indication of malfunction may be
present until the airplane begins a descent.
Figure 18-10. Effects of blocked pitot-static sources.
If the static reference system is severely restricted, but not entirely blocked, as the airplane descends, the static reference pressure at
the instruments begins to lag behind the actual outside air pressure. While descending, the altimeter may indicate that the airplane is
higher than actual because the obstruction slows the airflow from the static port to the altimeter. The VSI confirms the alti meter’s
information regarding rate of change because the reference pressure is not changing at the same rate as the outside air pressure. The
airspeed indicator, unable to tell whether it is experiencing more airspeed pitot pressure or less static reference pressure, indicates a
higher airspeed than actual. To the pilot, the instruments indicate that the airplane is too high, too fast, and descending at a rate much
lower than desired.
If the pilot levels off and then begins a climb, the altitude indication may still lag. The VSI indicates that the airplane is not climbing
as fast as actual. The indicated airspeed, however, may begin to decrease at an alarming rate. The least amount of pitch-up attitude
may cause the airspeed needle to indicate dangerously near stall speed.
Managing a static system malfunction requires that the pilot know and understand the airplane’s pitot-static system. If a system
malfunction is suspected, the pilot should confirm it by opening the alternate static source. This should be done while the airplane is
climbing or descending. If the instrument needles move significantly when this is done, a static pressure problem exists and the
alternate source should be used during the remainder of the flight.
Failure of the pitot-static system may also have serious consequences for Electronic Flight Instrument Systems (EFIS). To satisfy the
requirements of Title 14 of the Code of Federal Regulations (14 CFR) part 23, section 23.2615(b)(2), information essential for
continued safe flight and landing will be available to the flightcrew in a timely manner after any single failure or probable
combination of failures. However, many of the light aircraft equipped with glass displays typically share the same pitot-static inputs
for the backup instrumentation. Since both systems are receiving the same input signals, both could fail if affected by obstructed or
blocked pitot tubes and static ports and create a difficult situation for a pilot flying in IMC. Some manufacturers combine both the air
data computer (ADC) and the attitude and heading reference system (AHRS) functions so that a blockage of the input system may
also affect the attitude display.
With conventional instrumentation, the design and operation are similar regardless of aircraft or manufacturer. By
comparing information between the six conventional instruments, pilots are able to diagnose common failure modes.
Instrument failure indications of conventional instruments and electronic flight displays may be entirely different, and
electronic systems failure indications are not standardized. With the wide diversity in system design of glass displays, the
primary display and the backup display may respond differently to any interruption of data input, and both displays may
function differently than conventional instruments under the same conditions.
It is imperative for pilots to obtain equipment-specific information in reference to both the aircraft and the avionics that fully prepare
them to interpret and properly respond to equipment malfunctions of electronic flight instrument displays. Rapidly changing
equipment, complex systems, and the difficulty or inability to simulate failure modes and functions can impose training limitations.
Pilots still should be able to respond to equipment malfunctions in a timely manner without impairing other critical flight tasks should
the need arise.
Abnormal Engine Instrument Indication
The AFM/POH for the specific airplane contains information that should be followed in the event of any abnormal engine instrument
indications. The table shown in Figure 18- 11 offers generic information on some of the more commonly experienced in-flight
abnormal engine instrument indications, their possible causes, and corrective actions.
Figure 18-11. Commonly experienced in-flight abnormal engine instrument indications, their possible causes, and corrective actions.