C4103 "Fam 7"

Last updated: 3 June, 2008 16:46 by Bryan Weatherup
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Engine failure indications
Engine instruments, in particular the N1 and ITT, are provided to assist in determining the condition of the engine. These instruments should be monitored closely on an active schedule to detect early indications of impending engine problems. An indication of impending engine failure or flameout may be preceded by unstable engine operation. One or a combination of symptoms may prevail such as fluctuating turbine rpm, torque, and ITT, illumination of fuel system warning lights, dropping oil pressure, loss of thrust, etc. In the event engine failure or unexpected flameout occurs, an airstart my be accomplished provided time and altitude permit. Do not attempt an airstart if the engine failure can be attributed to:

  1. A mechanical malfunction
  2. It was accompanied by an explosion, overheating condition, vibration,
  3. Strong fuel fumes in the cockpit, or fire.
  4. N1 tachometer indicates zero rpm (engine seizure)
  5. If you intentionally shutdown the engine.
Condition
Torque
N1
ITT
Prop RPM
FF
Oil Temp °C
Oil Press
ROLLBACK
Low
40-62%
dropping from normal
decaying below 2200 RPM
80-100 PPH
-
-
FLAMEOUT
0
10-12%
dropping to 200° C
if <110 KIAS, dropping to 200 RPM
<50 PPH
decreasing
~10 PSI
COMPRESSOR STALL
wild
wild*
wild*
minor surges
wild
-
-
(Possible flameout or overspeed)

Flameout
A flameout condition indicated by a drop in ITT, torque, and turbine rpm. Propeller rpm will remain at the rpm selected with the condition lever as long as the airspeed is maintained above 110 KIAS. If flameout was caused by fuel flow interruption, restart may be spontaneous within 10 seconds because of residual heat retention in the combustion chamber.

Fuel control stuck at minimum flow (Rollback)
Reduced fuel flow (rollback) is typical of a fuel control unit pneumatic sensing system malfunction. If engine will not respond to PCL movements and ITT and N1 indicate the engine is running at a very low power settings, advance the EPL in an attempt to regain control of engine power by use of the manual fuel control system.

Compressor stalls
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 my be caused by damaged or degraded compressor or turbine blades, disrupted airflow, or compressor bleed valve malfunction.

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, fuel flow go to maximum and the engine is unresponsive to PCL movements, execute UNCONTROLLABLE HIGH POWER procedures. Take advantage of the power available to climb to within dead engine glide range distance.

* The instant failure generally occurs due to fuel starvation and dependent upon altitude, may require immediate response. Impending engine problems may be prefaced by loss of oil pressure, excessive ITT, fluctuating N1 or prop rpm, vibrations, chip light, etc..

T-34C glide characteristics

Several of the many factors that affect power-off glide performance can usually be controlled to some degree by the pilot. Primary among these controllable factors are airspeed, aircraft configuration (gear, flaps, canopy), propeller condition, angle of bank, and balanced or unbalanced flight. Maximum range power-off glide airspeed (VBEST GLIDE) differs with changes in aircraft configuration. Power-off glide performance at any particular VBEST GLIDE will be optimized with a closed canopy, feathered propeller, and level wings in balanced flight.

Gear
Flaps
Condition
V best glide (KIAS)
Descent rate 100KIAS (FPM)
Glide ratio
-
-
FTHR
100
800
12:1
DOWN
-
FTHR
87
1200
8:1
-
DOWN
FTHR
93
1250
8:1
DOWN
DOWN
FTHR
88
1650
6:1
-
-
UNFTHR
117
2400
3:1

With both canopies open, the sink rate typically increases by 300 fpm. Rate of sink changes as altitude changes.

Emergency voice reports
Emergency voice reports consist of Identification, Situation, Position, and Intention (ISPI). Emergency reports of an immediate or serious nature are prefaced by the word, "MAYDAY." Emergency reports of a delayed or less serious nature are preceded by the words, "PAN-PAN." Repeating either word three times is the widely accepted method of clearing the frequency for an emergency voice report (ISPI format).
I "MAYDAY, MAYDAY, MAYDAY,
Ranger ______,
"PAN-PAN, PAN-PAN, PAN-PAN,
Ranger _______,
S ENGINE FAILURE, CHIP LIGHT,
P SEVEN MILES SOUTH OF NAVY CORPUS AT 3500 FEET, OVER MALAQUITE BEACH AT 2000 FEET,
I INTEND A FORCE LANDING ON THE MUD FLATS." INTEND A PRECAUTIONARY EMERGENCY LANDING AT WALDRON"


New Maneuvers for this event:

When should I feather the prop?
Check the VSI while descending at 100 KIAS clean. A descent rate in excess of 600-800 fpm will require the propeller to be feathered.

Feather while airborne
This maneuver will not be performed by the student. The zero-thrust torque setting for the T-34C is 205 ft-lbs at VBEST GLIDE of 100 KIAS with gear and flaps up. This power setting approximates the performance of the aircraft with the propeller feathered.

  1. 5000 ft+ AGL over a hard surface runway. Trim for 100 KIAS glide (torque at 200 ft-lbs). Note the rate of descent and nose attitude.
  2. PCL - IDLE (note the deceleration and increased rate of descent)
  3. Condition lever - FTHR (note the acceleration effect and decreased rate of descent as the prop goes to +87.5 degrees)

    To return to normal propeller operating speed:
  4. Condition lever - FULL INCREASE RPM (note the time it takes for the propeller to return to governing range, and deceleration at flat pitch) NOTE - the propeller should unfeather in approximately 15 seconds.
  5. PCL - NORMAL OPERATING RANGE AFTER PROPELLER RPM RISES TO A STABILIZED RPM.

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