a. Compressor stall
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.
2. Demonstrate:
a. Low altitude power loss from the pattern (LAPL(P))
The simulated Low Altitude
Power Loss (LAPL) in the pattern will be initiated above 800’ AGL by the
instructor reducing the power to 200 ft-lbs torque and informing the student
there is a simulated power loss.
The power loss on takeoff
will require immediate reaction to prevent catastrophic results.
About the only recourse for the pilot in this situation is to land straight
ahead changing direction only to avoid major obstacles. Do not try
to turn back to the runway from which you departed. Making a crash
landing straight ahead with the aircraft under control affords a much higher
likelihood of survival than an uncontrolled crash. Depending upon
your altitude, you may be able to reach an off duty runway if it is forward
of the wings. On entry to any airfield, an alert pilot will take
notice of the options available in the event a failure occurs ANYWHERE
in the pattern. Obviously, the most critical area is that from takeoff
until commencing the crosswind turn. Thereafter, your options will
greatly improve as an off duty runway will probably be within gliding distance
IF THE FIRST SIX PROCEDURES OF THE LAPL ARE EXECUTED.
Procedures:
1) DUMP. Obtain
a safe flying speed by lowering the nose. If in a climb with the
gear and/or flaps down, the aircraft will rapidly decelerate toward stall
speed. Immediate forward stick is required while you simultaneously
asses (CHECK) the engine difficulty.
2) If a rollback condition exists, use the EPL for power.
3) SUCK. FEATHER. If not, feather the prop and raise the gear and flaps while you are setting up for the landing (POINT).
4) LOCK. Check your harness locked prior to landing.
5) Altitude permitting, disconnect the fuel source by placing the condition lever to fuel off and pulling the t-handle.
6) CONFIGURE THE AIRCRAFT AS APPROPRIATE. Lower the flaps whenever the landing site is made. Or gear if able to make it to an off-duty runway.
7) BROADCAST. MAYDAY report:
ICS “MAYDAY, MAYDAY, MAYDAY, 6E123, ENGINE FAILURE, 3 MILES NORTH OF BARIN AT 1400’, I PLAN TO LAND IN A FARMER’S FIELD.”
8) CANOPY. Blow.
9) BATTERY. Secure.
Common errors:
1) Not lowering the
nose to maintain safe flying airspeed - 100 kts.
2) Not feathering
prop (simulated).
3) Not cleaning up
the aircraft’s configuration.
4) Failure to lower
flaps when field is made.
5) Poor field selections.
6) Failure to intercept
ELP profile when possible.
7) Getting too verbose
with the “MAYDAY” call. Fly the aircraft, be brief with the call.
b. PPEL from the pattern (PPEL(P))
Purpose. Utilize the
PEL procedure to ensure that a safe landing at a paved field can be made
if indications of an impending engine failure should occur. Indications
of an impending failure or power loss are: system malfunction, excessive
vibration, smoke or fumes, chip detector annunciator light, fuel leaks
or siphoning, prop malfunction or any other condition listed in NATOPS
requiring that you land as soon as possible due to impending engine/airframe
problems.
Although the situations
requiring a PEL are impending engine failures, unlike the total power loss
situations, POWER IS AVAILABLE and should be used to reach High Key, Low
Key, and the runway at a paved field. Utilize maximum power (1015
ft-lbs) if the emergency is not related to the Oil System or strong engine
vibrations, if related, use 850 ft-lbs torque and climb at 120 knots.
Realize that power may cease at any time, anticipate forward stick to maintain
flying speed should this occur.
Procedures:
1) TURN towards the nearest paved field.
NOTE - For PPEL’s turn towards the nearest manned OLF designated for PPEL’s. Realize that for actual conditions, you would land at the best suitable field commensurate with altitude and gliding distance.
2) CLIMB to intercept at or below HIGH KEY. LOW KEY is probably going to be your best option. Use a 120 kt climb with 1,015 ft-lbs (850 if oil related). In an actual emergency, use a 100 kt climb attitude to increase your rate of climb. Once on profile, pull power to 200 ft-lbs, transition to a 100 kt glide. Do not lose sight of your landing field by turning the aircraft away from it (remember, you just took off a few seconds ago).
3) CLEAN with gear and flaps up and report
ICS “AIRCRAFT CLEAN”
4) CHECK engine and flight instruments. Try to ascertain the cause and functional status of the aircraft.
5) DETERMINE. The runway shouldn’t have changed in the last 2 mins.
6) DELIVER PAN voice report using ISPI format to RDO
ICS (UHF if actual) “PAN-PAN, PAN-PAN, PAN-PAN, 6E123, FUEL PRESSURE LIGHT IN FLIGHT, 8 MILES WEST OF BREWTON AT 5500 FT, I INTEND TO EXECUTE A PEL TO RUNWAY 32”
7) REDUCE torque to 200 ft-lbs and transition to a 100 kt glide when back on profile. Drop your gear as soon as you intercept X-WIND/LOW KEY.
8) REPORT landing checklist
ICS “HARNESS LOCKED, GEAR THREE DOWN AND LOCKED, BRAKES PARKING BRAKE OFF, BRAKES PUMPED FIRM, ENGINE INSTRUMENTS CHECKED, LANDING LIGHTS ON”
9) CROSSWIND (2000’ AGL, 100 KIAS) Vary your AOB to arrive 2/3 WTD out at Low Key. This is your only valid crosscheck if you are at the proper altitude.
10) LOW KEY (1200’, 100 KIAS, 2/3 WTD)
CH X “BARIN RDO, 6E123, PATTERN LOW KEY, GEAR DOWN AND LOCKED”
11) FLAPS if required and the field is made
12) 90 POS (600-800’ AGL, 90 KIAS)
ICS “GEAR DOWN, FLAPS (UP/DOWN), LANDING CHECKLIST COMPLETE”
13) FINAL (1200-1500’ straight-away, 90/95 KIAS)
ICS “GEAR DOWN, PADDLES CHECKED”
14) Reduce power to idle for the transition to touchdown at the intended point of landing.
NOTE - Touchdown is made on the main gear, then gently lower the nosewheel as in a normal landing. The descent to final will generally be at a greater rate than for normal touch-and-go’s. Adjust nose attitude and power in the flare to transition to a normal landing. If making a full stop, apply BETA and braking commensurate with runway remaining. Should insufficient runway remaining preclude a full stop before going off the runway execute a waveoff if in the pilot’s judgment the engine will continue to develop sufficient power to obtain a low key position for another attempt. If the pilot feels that the engine is not reliable for another attempt, utilize NATOPS ABORTED TAKEOFF procedures.
NOTE - When executing a PEL with the EPL, exercise caution in power
application to prevent a compressor stall. Be sure the EPL is in
either DISCONNECT or IDLE before selecting BETA with the PCL.
3. Introduce:
a. LAPL
4. Practice:
a. Course rules/COMM/IFF/HFE
b. ATS
c. Spin
d. HAPL
e. PPEL
f. Landing pattern
g. Full flap landings
h. No flap landings
i. Waveoff
5. Non-graded:
a. Ground procedures
b. Takeoff/departure
c. TP
d. OFO