107 Components

Question 1

What components are driven by the aft transmission?

Answer 1

Two AC generators & Aft transmission pump
(mounted on the bottom of the transmission and driven by an accessory drive gear)

Nr tachometer generator & the rotor overspeed sensor
(mounted on, and driven by, the aft transmission oil pump)

WARNING: losing NR & AFT XMSN oil pressure simultaneously indicates the oil pump has failed and transmission failure is imminent.
“IMMINENT XMSN FAILURE” EP

Question 2

Generators

Answer 2

2 Generators
3-phase AC power (ABC)
Mounted on and driven by aft transmission
115V (to ground) / 208V phase to phase
20 KVA / 400 hz
One primary, one standby
Air cooled
Can be reset w/switch (or AUX BATT flash if complete electrical failure)

Question 3

Negative Sequence Relay

Answer 3

Monitors 3-phases of AC bus
If one phase (AB or C) isn’t getting the same power, FEEDERS FAIL light illuminates

Question 4

Main Battery

Answer 4

25.8 V
DC - Direct Current
SLAB - Lead Acid
Backup electrical power in case generators fail
Used for starting

Question 5

AUX Battery

Answer 5

24 VDC
Located in companionway
Provides ‘Keep Alive” power to Engine Control System
Can be used to field flash the generators (reset)

Question 6

AC Feeder Failure

Answer 6

AC FEEDER FAIL (red warning light) illuminates when a fault is detected in the selected feeder.

Pilot must manually switch feeders (no automated switching)

Loads of AC electrical will occur until pilot manually selects operable feeder: AC BUS FEED (NORM/AUX)

STM 5-3

Question 7

AC Bus Feeders

Answer 7

Transfer electricity from AC distribution panel to cockpit circuit breakers
Either NORM or AUX feeder wires/lines can transfer electricity
Cockpit switch AC BUS FEED enabled pilot to select NORM (with both generators on and switch in norm, the #1 Gen power AC bus via normal feeders)

Question 8

Hydraulic Brake Systems

Answer 8

Two hydraulic break systems:
Rotor Brake
Wheel Brakes

Both systems are self-contained

Question 9

Rotor Brake Description

Answer 9

Self-contained hydroelectric unit (28 VDC)
Single disc brake
Mounted on aft end of forward transmission input

Used to stop rotors expeditiously in gusty or high wind conditions to minimize possibility of blades striking the tunnel

Question 10

Rotor Brake - operation

Answer 10

• When arming lever up and switch held in on position
• Self-contained hydroelectric unit
  - 28VDC motor pumps hydraulic fluid 550PSI
  - Takes five seconds to fully engage pads on disc
  - Turns off over 800 PSI
  - Back on below 600
  - Over 900 PSI pressure relief valve
  - Pressure switch/ 10 +/-2 PSI/ ROTOR BRAKE ON
  - Should be fully engaged by 40% NR

Operation: Aply rotor brake prior to 45% Nr
•Must be fully engaged prior to 40% NR to prevent cracking of fwd XsmN case

Question 11

Rotor Brake Unit
(description)

Answer 11

disc bolted to fwd transmission input shaft
w/ hydraulically operated friction pads
stop the disc stops the entire drive train

Question 12

Rotor Brake Safety Features

Answer 12

1) prevent the brake from being applied when either ECL is beyond the START position

2) prevent the ECLs from being advanced beyond
START if the rotor brake is already engaged

Question 13

Rotor Brake Start

Answer 13

Start the aircraft with rotor brake engaged
When ready to go to fly, release warning lever and immediately start advancing ECL(s) up to 40% NR to help prevent tunnel strike

Question 14

Rotor Brake Components

Answer 14

Rotor Brake Unit
Power Package
Rotor Brake Arming Lever
Rotate Brake Control Switches
ROTOR BRAKE ON - warning light

Question 15

Rotor Brake EP’s

Answer 15

“EMERGENCY A/C SHUTDOWN”

Question 16

Rotor Brake Arming Lever
(description)

Answer 16

• UP = armed: physicaly blocks ECLs →FLY interlock alows for activation of brake; ECL’s must be below FLY to Arm brake
•DOWN = disarmed: interlock prevents rotor brake activation
•AC Freq. Relay: one on each ECL, electicaly prevents rotor brake activation if ECL In FLY.

Question 17

Rotor Brake Control Switches
(description)

Answer 17

1) Cockpit switch (ON, NORMAL, OFF)
- works in conjunction w/ interlock / arming lever
- with arming lever up & DC power applied
- hold brake on 5 seconds
- release with switch or disarm
2) Remote switch on fwd XSMN cowling for MX

Question 18

When does the ROTOR BRAKE ON - warning light illuminate?

Answer 18

anytime pressure exceeding 10±2 PSI is detected in the system

Question 19

Rotor Brake Power Pack
(description)

Answer 19

Mounted on fwd transmission.
• motor operated pump: pressurizes fluid to 550 PSI in ~ 5 seconds
•combined reservoir/accumulator: dampens pressure surges and compensates for thermal expansion/contraction
•pressure switch: inturrupts elec. power to pump if system pressure >800 PSI; reactivates when < 600 PSI
•relief valve: returns excess pressure if >900 psi
•glass dome indicator + manual release plunger (red when brake applied)