Blade Fold Wing Stow Flashcards
How long does the BFWS sequence take
90 seconds to stow, 60 seconds to unstow the wing and 30 seconds to unfold the blades
RPU
Rotor Positioning Unit - A hydraulically operated drive speed reduction unit, mounted on the Midwing Gearbox (MWGB). Its primary purpose is to rotate the proprotor blades to the desired position for BFWS operations.
RPU Proximity Sensors
Provide a LOCKED, INDEX, or FLY position signal to the Mission Computers during the selected BFWS sequence.
Slip Ring Assembly
Provides an electrical interface between the stationary nacelle and the rotating electrical components mounted on the proprotor assembly
Which blade does not fold
The red blade
Stow Ring
Fastens the wing to the fuselage. It allows the wing to rotate to the stowed position.
What is the primary indication that the wing is in flight ready or full stow condition
Lockpins and 57 degree switches; 4 wing lockpins are reequired to be engaged in the flight ready position. There are 2 lockpin indicators on each side of the fuselage
Lockpin indications for locked and unlocked
Unlocked = the checkerboard black and white patternLocked = solid black
Conducting BFWS above __ may damage the Blade Fold Planetary Assembly
45 kts
Ship Motion Limitations
Should not exceed 3 degrees pitch and 15 degrees roll when executing BFWS sequence
Temperature below ___BFWS will be sluggish taking __ minutes, and below ___ will take ___ minutes
-29 degrees C, 3 minutes-40 degrees , 8 minutes
Purpose of the BFWS
to reduce the overall dimensions of the aircraft for shipboard operations and hangar storage, and to provide access for maintenance.
5 BFWS Positions
- Flight Ready2. Maintenance3. Fold Horizontal4. Fold Vertical 5. Fully Stowed
6 BFWS Maintenance Positions
- Rotor Lock2. Fold Horizontal 3. Fold Vertical4. Maintenance Red5. Maintenance White6. Maintenance Green
Resolver Select Key on the BFWS SYST Layer
Monoplane sensors determine the rotor azimuth and speed for the BFWS. This key is used to select either the left or right resolver in the event of ROTOR POSITION UNKNOWN or ROTOR POSITION RESOLVER DISAGREE
BFCU
Blade Fold Control Unit - Actuates the Blade Fold Relay Assembly to control the blade fold operation
Blade Fold Relay Assembly
Interfaces with the Cockpit Management System (CMS) to regulate, sequence, and control signals from the CMS to the BFWS system
BFWS Power Module
Mounts inside the blade bolt and has an electric motor and gear train that folds the blade
Blade Fold Sensors
Detects when blade fold is complete and sends a message to the MC
Shear pin sensor
Sense a system jam an prevent overloading of the blade actuator assembly by stopping the blade fold sequence when a jam is sensed. There are 2 sensors per blade
Blade Latch Pin Sensor
Lock the blade in flight position and react to blade beam wise loads
Capstan Drive Actuator
Winds the cable to rotate the stow ring and wing. Has a mechanical connection to allow manual wing stow in case of electrical or hydraulic failure
What will improve BFWS performance in cold weather
Preheating of the midwing gearbox area above 29 degrees C
What conditions will trigger BFWS NOT FLIGHT RDY Caution
- Wing is not locked2. Left BFCU is operational and left blades are not unfolded3. Right BFCU is operational and right blades are not unfolded4. RPU is either coupled or locked5. BFWS is in progress and BFWS deadman switch is not enabled
What conditions trigger BFWS FAULT Advisory
- Rotor Phase unit fail2. BFWS in progress and Flight ready switch, stow switch or 57 degree switch has failed.
BFWS FAULT Advisory Procedure
Monitor EICAS for BFWS NOT FLT RDY
BFWS NOT FLIGHT RDY Caution Procedure
- Maneuver Severity - Reduce2. Land as soon as possible
What powers the BFWS
The utility subsystems portion of HYD 3
Procedure if you get BFWS Halt
Contact maintenance regardless of the reason for the halt
