Dash 1 Section 1 Flashcards
What kind of aircraft is the T-6A?
A single engine, two-place (tandem), pressurized, low-wing training aircraft made by Beechcraft and approved for day or night VFR and IFR flight
What is the T-6A powered by?
Pratt and Whitney PT6A-68 free turbine turboprop engine with a Hartzell four blade prop
What type of landing gear does the T-6 have?
A retractable tricycle type which is electrically controlled and hydraulically operated
What is the definition of max abort speed?
The maximum speed at which you can bring the aircraft to a stop in the remaining runway.
What is the definition of max braking speed?
The speed at which maximum braking effort will bring the aircraft to a stop without exceeding the maximum brake absorption energy (3.96 million ft-lbs).
What type of engine is the PT6A-68?
A reverse-flow free-turbine turboprop engine
How much thrust does the PT6A-68 produce?
1100 SHP, 2900 ft lbs torque, 2750 lbs of thrust at SL
What are the three engine sections?
The gas generator, the power turbine and the reduction gearbox
What is the capacity of the oil system?
18.5 US quarts
What are the oil system components?
Pressure, scavenge, cooling and breather
Describe airflow’s movement through the engine.
Rearward through intake duct–>through inertial separator–>annular plenum case–>four stage axial compressor and centrifugal compressor–>through diffuser tubes and straightening vanes–>combustion chamber–>ignited gases drive single stage gas gen turbine which drives compressor–>two stage power turbine drives reduction gearbox–>ejected out exhaust stacks
What is the diameter of the prop?
97”
How long is the aircraft from nose to elevator?
33’ 4”
How long is the T-6 from wingtip to wingtip?
33’ 5”
How wide is the horizontal tail?
11’ 4”
How tall is the T-6 from the ground to the top of the vertical tail?
10’ 8”
When must oil level be serviced?
Within 30 minutes of engine shutdown
For most accurate results check the oil level when?
15-20 minutes after engine shutdown
Describe the oil pressure system.
Two oil pickup elements, one in the center of the tank and another which picks up oil near the top of the tank in inverted flight.
Describe the oil scavenging system.
Two dual element gear type pumps, one inside and one outside of the accessory grbox which return scavenged oil from the bearings and gearbox and routes scavenged oil through the oil cooler
The engine oil pressure indicator may display oil pressures up to what with the engine shut down?
4 psi
When does the red OIL PX annunciator go on?
Either when oil pressure is at or below 15 psi at IDLE, when oil pressure is between 15 and 40 psi at IDLE for more than 5 seconds, or when oil pressure is below 40 psi above IDLE
When does the amber oil PX annunciator go on?
Either when the oil pressure is between 15 and 40 psi at IDLE or between 40 and 90 psi for 10 seconds above IDLE
The reduction gearbox reduces power turbine output shaft speed of what to propeller operating speed of what?
30,000 RPM; 2,000 RPM
Describe what components are mounted on the reduction gearbox.
A chip detector; propeller interface unit (top), torque probe (top), and permanent magnet alternator (top); air conditioning compressor (right side)
100% torque is available between which two altitudes on a standard day?
Sea level to 12,000’-16,000’ MSL
What controls the propeller pitch?
The PMU and PIU
What are the 3 basic conditions of prop pitch and what do they represent?
Feathered, low pitch for low speeds and low throttle settings, high pitch (between feather and low pitch)
When at low pitch the prop blade angle is approximately how many degrees from the reference plane?
15
How does the PIU/PMU control prop pitch?
The PMU sends a signal to the PIU which varies the oil pressure in the prop shaft through a transfer sleeve. Pressurized oil forces a piston forward which makes the pitch lower (more fine) or reduces oil pressure which drives a piston backwards and makes the pitch higher (more coarse)
With the PMU functioning the mechanical overspeed governor limits Np below what?
106%
The electronic governor with the PMU on will keep the prop functioning at what?
100%
The mechanical fly weight overspeed governor keeps Np at what with the PMU off (think overspeed governor check)?
100+/-2%
How does manual governing work?
The centrifugal force moves counterweights outwards causing oil pressure to dump and the feathering spring to make the pitch higher (more coarse) to keep Np in limits.
What are the two methods to feather the prop and how do they work?
- Engine shut down with PMU NORM
- Placing the PCL to cutoff
The PMU sends a signal to the prop servo valve to drain prop oil pressure
The PCL to OFF activates micro switches that power the feather dump solenoid valve which drains prop oil pressure.
When will the PMU abort a start (specific parameters)?
- If no light-off within 10 seconds of AUTO/RESET with the STARTER switch
- If ITT exceeds 940 deg C for 2 seconds, 870 deg C for 4 seconds, or 840 deg C for 19 seconds
- If N1 acceleration rate to IDLE is 50% of normal.
What five parameters may cause the PMU to abort a battery start attempt?
High IOAT; high ITT; weak battery; tailwind; high density altitude
What powers the PMU?
The PMA
The PMA supplies how many volts to the PMU?
32 VAC
The PMU automatically switches to the 28 VDC battery bus when what?
When prop RPM drops below 40-50% RPM or when the PMA fails
What controls whether the PMU operates in flight or ground mode?
The weight on wheel switches
What does it mean if an EDM FAIL message appears on the lower portion of the EID screen?
EID is not receiving all data in proper format; only the dashed out parameters/missing pointers are invalid.
What is the only signal which is processed before going to the AEDD?
Torque
For engine starts between what ranges of IOAT does the PMU default to 121 deg C?
When IOAT is between 96 and 121 deg C. If IOAT is above 121 deg C the PMU will go offline. If the PMU is activated with an IOAT at or above 96 deg C, IOAT and ITT info will be invalid (dashes) and the display will read EDM FAIL in the lower portion.
What are some of the approximate PCL handle positions?
OFF- -5-0 deg PROP FEATHER-7 deg AUTO START-20 deg BOOST PUMP-27 deg IDLE-30 deg GEAR WARNING-45 deg (mid range) SPEED BRAKE-77 deg MAX POWER-80 deg
What does it mean if the IGNITION switch is set to NORM?
The PMU controls the igniters
What non-engine related functions does the EDM perform?
Fuel balancing, fuel quantity indication, display of DC volts, amps, hydraulic pressure, cockpit pressure altitude and cockpit differential pressure
What does EDM A/B FAIL and EDM FAIL mean?
If one output is bad or either data bus channel fails. EDM FAIL means that the EDM has failed.
Which FP FAIL numbers apply to which probe?
0-collector tank fuel probe 1-left inboard 2-right inboard 3-left middle 4-right middle 5-left outboard 6-right outboard
What does a CONFIG ERROR on an EID mean?
Invalid or missing configuration straps for EID.
The ST READY light illuminates for how long regardless of position?
3 seconds
When do the starters and igniters deenergize?
At approximately 50% N1
What does “shall” and “will” mean in technical orders?
A mandatory requirement.
What does “should” mean?
A non mandatory, desired or preferred method of accomplishment.
What does “may” mean in technical orders?
An acceptable or suggested means of accomplishment.
What is a warning?
An operating procedure, technique etc which could result in personal injury or loss of life if not carefully followed.
What is a caution?
An operating procedure, technique etc which could result in damage to equipment if not carefully followed.
What is a note?
An operating procedure or technique etc which is essential to emphasize.
When will cycling the PMU switch work if there are dashed out values?
If the rate of change of the dashed out values exceeded the PMU sensor validity check limit. If the dashes are actually because of a sensor failure, though, cycling the switch will not fix it.
What should you do if the IGN SEL annunciator remained continuously illuminated?
Just notify maintenance personnel after the mission.
How is the PCL connected to the FMU?
Mechanically and electrically.
True/False. There is PCL friction adjustment in both cockpits.
False. Only the FCP
What non-engine related functions does the EDM perform?
Fuel balancing, fuel quantity, DC volts, DC amps, hydraulic pressure, ckpt pressure altitude and ckpt differential pressure.
Above what altitude does the PMU raise N1 to maintain Np above 80% to avoid prop stresses?
10,000’ PA
The PMU will abort a start based on ITT if what?
ITT exceeds:
1) . 940 deg C for 2 seconds
2) . 870 deg C for 4 seconds
3) . 840 deg C for 19 seconds
4) . N1 acceleration rate is less than 50% of normal
What does it mean if the ST READY light goes out?
The PMU is no longer monitoring the start.
True/False. During an airstart the PMU does not provide engine protection.
True.
What is the maximum increase and decrease in power when the PMU goes to manual mode?
280 shp
550 shp
How does the fire system work?
Dual sensor tubes with helium gas and a hydrogen charged core. The core responds to localized heat. The helium responds to overall high temp. The expanding helium pressurizes a diaphragm which trips an electrical circuit which sets the FIRE annunciator.
True/False. Flattening, twisting, kinking or denting of the fire warning loop will not affect test or flight operation.
True.
What does the firewall shutoff handle turn off?
Fuel, hydraulic fluid and bleed air
The fuel system provides how much fuel through single point refueling? Through over the wing?
1100 lbs; 1200 lbs; 100 lbs is 15 gallons
When parking on ramps with greater than 1% slope, the fuel system may do what?
Vent fuel overboard through a pressure relief valve.
When will the transfer valve close the motive flow to the light tank (fuel balancing)?
When 20 lbs has been detected for more than 30 seconds.
When does the FUEL BAL annunciator illuminate?
If fuel imbalance is not reduced to less than 30 lbs in 2 minutes.
What does the red FUEL PX annunciator mean?
Less than 10 psi fuel pressure in the motive flow line.
When is the BOOST PUMP annunciator illuminated?
1) . BOOST PUMP switch is ON
2) . PCL above IDLE position and low pressure
3) . Whenever STARTER switch is activated
When do the amber L FUEL LO and R FUEL LO annunciators come on?
When the optical sensors indicate below 110 lbs in the respective wing tank.
When should you not attempt to manually balance the fuel load?
With FP FAIL on the AEDD
How many fuel probes are there and what fuel readings do they provide?
Seven, three in each wing, one in the collector.
Outer probe: 445 +/-50 lbs
Middle probe: 308 +/- 50 lbs
Inner probe: readings until approximately 20 lbs
How is positive pressure maintained in the collector tank?
Gravity from wings to center. During inverted flight a weighted rod closes off normal fuel pickup and activated inverted flight pickup.
How long does the inverted fuel pickup work?
At least 15 seconds.
What happens if the low pressure fuel pump fails?
High pressure pump can suction feed sufficient fuel; BUT if the engine flames out, you cannot restart it.
What’s in the electrical system?
- 28 VDC, 300 A starter/generator
- 24 VDC lead acid battery 42 Amp-hr
- 24 VDC auxiliary battery 5 Amp-hr
- external power receptacle
The generator needs to supply a minimum of how many volts to charge the battery?
25 V
If there’s a red GEN annunciator what will happen?
Air conditioning will automatically be shed.
Where is the aux battery located?
The left avionics bay
The auxiliary battery will power standbys for how long?
Approximately 30 minutes.
What’s a consideration with the aux battery and the radio?
Excessive radio communications will reduce available battery time.
Do not connect external power with what battery voltage?
22.0 V
If the GEN BUS has failed and the BUS TIE is in the NORM position what will happen?
The items on the gen bus will not be powered but the generator will continue to charge the battery.
What kind of system is the brake system?
Non-boosted, mechanically actuated, hydraulically operated system.
What determines the braking force being applied?
The pilot applying the most pedal force.
What do the three bands on the filler plug mean?
Top line means system needs servicing, green middle band means it’s good, bottom line means it’s over serviced.
What capacity is the hydraulic system?
5 quarts
When does the pressure relief valve begin working?
3250-3500 psi
To what does the hydraulic pump pressurize the normal system and accumulator?
3000 +/-120 psi
When can the system power the associated hydraulic based systems?
1800 psi; if it drops below that HYDR FL LO annunciator will come on
What does the HYDR FL LO light indicate?
The reservoir level has dropped below approximately 1 qt
With the HYD SYS circuit breaker open what will be available?
Pressure indication and HYDR FL LO sensor will not be available but EHYD PX LO will be available.
When does the EHYD PX LO light come on?
2400 +/-150 psi
What does the check valve do?
It prevents the emergency system from bleeding back into the main system
What does the hydraulic fuse check?
It prevents a leak in the emergency system from depleting the main system. It’s restricted to less than 0.25 gallon/minute
In the event that there’s a system leak how much fluid loss can you have (if the leak exceeds 0.25 gallon/minute)?
0.5 quarts
What kind of landing gear is on the T-6?
A retractable tricycle landing system with four actuators, one for each gear and one for the main gear doors
When does the gear handle turn red?
1) . Whenever the nose gear is in transit or main gear doors are not down and locked
2) . PCL is approaching IDLE with the gear handle UP
True/False. If the gear handle is difficult to raise use the DOWNLOCK OVERRIDE button to raise it.
False. If the WoW micro switch has failed (on the right) the downlock override can be used to raise the gear handle without raising the gear.
The landing gear system is _______actuated and __________sequenced.
Hydraulically; electrically
Normal gear extension/retraction takes how long?
6 seconds approximately.
