ALFS Flashcards
Cable Angle corrective actions in order
- Use cyclic trim (4-way) to command the aircraft in the corrective direction.
- Fly against lateral trim.
- Using trim release button, reposition aircraft.
- Fly against longitudinal trim.
If RADALT hold fails or malfunctions in coupled hover, the use of BARALT is not recommended for what?
continued dipping operations in moderate or heavy sea states
Cable Angle Hover requirements
“Nickel Dime Wet, +3”
- Groundspeed less than 5 knots
- RADALT within 10’ of selected alt. hold
- Dome wet indication
- AFCS DEGRADED not illuminated
- AUTO PLT engaged
- DPRT or CREW HVR not engaged
Cable angle hover mode disengagement occurs:
- Automatically when dome is raised thru 27 +/- 12’ water depth (if SUBM OVRD not engaged)
- When cable angle hover mode is manually disengaged
- If the difference between RADALT and selected alt. is > 10’
- When both cable angle longitude an latitude sensor channels fail
- When HVR pushbutton on AFCS CONTROL panel is manually disengaged
What are the six operating modes of the reeling machine?
- Automatic (remote) hydraulic
- Manual (RMCU) hydraulic
- Aux hydraulic
- Aux electric
- Aux hardware electric
- Hand crank
ALFS: Approximately how many feet of cable is on the reel?
2550’
AUX Hydraulic Mode functionality
Allows operator to manually control the servo valve in the event of a RMIU failure, bypassing the RMIU and RMCU.
Does not have the following:
- Safety interlocks
- Auto stop at trail
- Seats or locks the TA
- ESD protection
Requires only hydraulic power and 28 Vdc.
DO NOT lower TA into the water in AUX HYD because ESD is bypassed. Can only lower when TA is submerged.
AUX Electric Mode functionality
In Auxiliary Electric mode, the reeling machine uses the auxiliary motor to drive the gear train assembly.
- Full safety features
- Will stop at trail, seat, and lock TA
- Cable raise speed 6’/sec (slower than usual)
- Utilizes AC electric power
- Only operates in raise
Requires 115 Vac, 3-phase, 400 Hz power.
[CAUTION]: Except when executing sonar troubleshooting, AUX Electric shall only be used when TA is submerged.
AUX Hardware Electric Mode functionality
In Auxiliary Hardware Electric mode, the reeling machine uses the auxiliary motor (AC power) to drive the gear train assembly. Controlled by RMCU, bypassing RMIU.
Does not have the following:
- Safety interlocks
- Auto stop at trail
- Seats or locks the TA
- Only operates in raise
Used as a last resort to recover TA when failures prevent use of any other mode.
When would you use Hand Crank Mode to control the reeling machine?
used only for maintenance purposes
The following should be performed for all sonar malfunctions, caution lights, or error codes:
- Alert the crew.
- Execute Reeling Machine Malfunction emergency procedure.
- Complete the Sonar Troubleshooting checklist.
After how many faults requiring an Aux mode of operation do you need to cease dipping operations?
2 consecutive faults
How many unknown error codes can you clear before you have to cease dipping operations?
Unknown error codes should not be cleared more than three times. Upon clearing unknown error code the third time, the crew shall cease dipping operations
How much battery charge is needed to unfold the array?
10%
The presence of a steady ________ RMCU error code could indicate a loss of TA or severed sonar cable.
1177
Which landing site is the primary consideration when recovering a hung dome?
primary consideration shall be given to recovering a hung dome ashore or aboard aviation ships (CVN or LHA/LHD)
air capable ships may be considered if ambient conditions and POCL permits pilots’ adequate reference to position the helicopter
Raise speed limiter function
- Works with servo-valve on hydraulic motor to ensure raise speed does not exceed a set threshold
- Ensures safe TA approach speed
- Does not provide any function during lowering
- Does not function during AUX Hydraulic or AUX Hardware Electric modes
- [RSL FAIL] error if threshold exceeded
ESD protect functionality
At approx. 20' below the aircraft the RMIU commands the ST/R into ESD protect mode. This disconnects the TA from the ST/R prior to water entry.
ESD protection disabled when the submerged switch and depth sensor within the TA both indicate that the TA is submerged and the RMIU detects a change in cable tension as the TA enters the water. 28' - 40' depth.
Automatic Approach
can be initiated at any airspeed and altitude < 5000’ AGL
On profile >40kts: 215fpm descent / 2.5kt/sec decel.
On profile <40kts: 130fpm descent / 1.5kt/sec decel.
Above profile: 360 fpm descent / airspeed hold
Below profile: RADALT hold / 2.5kt/sec. decel.
Automatic Departure
can be performed from a coupled hover or automatic approaching will terminate at 150’ / 120kts
Profile:
< 85kts: 3kt/sec accel. / 240fpm climb
>100kts: 1kt/sec accel. / 240fpm climb
AFCC monitors torque to prevent increase >120% below 80kts and above 106% above 80kt.
Hover Coupler requirements
engages when:
- within 1 KGS of longitudinal velocity selected
- within 5 KGS if manually engaged
- RADALT engaged within 2’ of hover altitude selected
AFCC monitors torque to prevent increase above 116%
Cable angle hover display references when submerged and not submerged
submerged: cable’s vertical angle relative to the surface of the water
not submerged: cable’s vertical angle relative to the center of the funnel
Cable angle hover display associated numbers and cautions/warnings:
Inner ring = 4.25 degrees
Outer ring = 8.5 degrees
Tick marks = 2 degrees
[CAUTION] If the 4.25 inner ring is exceeded as the dome is leaving the water, there is an increased risk of the transducer striking the aircraft which may result in aircraft damage.
[WARNING] If the 8.5 outer ring is exceeded while the dome is leaving the water there is a significantly increased risk of the dome striking the aircraft, including the rotors which may result in aircrew injury or death.
How long does it take the AFCS to calculate a solution for current, winds, sea state, etc. in cable angle hover?
25 seconds
Which modes only raise and not lower?
- AUX Electric
- AUX Hardware Electric
Which modes have full safety features?
- Normal Hydraulic (Auto/Manual)
- AUX Electric
Which modes do not have safety features?
- AUX Hydraulic
- AUX Hardware Electric
When do you get the “Dome Wet” indication?
Once both the SUBMRG indicator and the ESD sequence is complete, the dome wet indication on the flight display will be displayed. Then Cable Angle hold is enabled.
RMCU
Reeling Machine Control Unit.
Contains operating controls and failure indications for the reeling machine and provides the means for lowering and raising the transducer.
In AUTO mode, preset depth commands may be issued from a menu, and acknowledged or cancelled via the RMCU. In MAN mode, the SO commands depth changes via the RMCU. The RMCU also contains indicators for monitoring reeling machine control system status.
RMIU
Reeling Machine Interface Unit
RMIU controls the reeling machine functions, regulates smooth transitions of transducer dipping activities, and performs the reeling machine BIT.
The RMIU also provides electrical interfaces between components of the dipping sonar system. There are no controls or indicators on the RMIU. It is on the starboard side of the reeling machine at the rear starboard corner of the aircraft cabin.
TILT indicator in RMCU
TA tilting > 10.5 deg
KITING indicator on RMCU
A kiting condition is when the cable is paying out at a greater rate than the TA depth is increasing.
BOTTOM indicator on RMCU
TA < 50’ from ocean floor
[CABLE ANGLE AT LIMIT]
Caution to alert the crew of potential cable damage.
The cable angle has exceeded 7.5 deg of total deflection relative to the center of the funnel.
Submerged Override
SUBM OVRD allows pilot to override the 27 +/- 12’ water depth requirement for engaging cable angle hover mode.
Cable angle must be manually disengaged when TA raised through 27 +/- 12’ water depth when using SUBM OVRD.
If cable angle hover fails to engage with TA submerged, pressing SUBM OVRD then pressing Cable Angle will engage cable angle hover mode.
[CAUTION] Failure to delay a minimum of _________ for oscillations to dampen at trail before raising to seat increases risk of damage to TA and cable.
two seconds
The auxiliary hydraulic control system provides the capability to raise or lower the TA in the event of a loss of _____________.
Normal reeling machine control
The auxiliary electric motor provides the capability to raise the transducer in the event of a loss of ___________________.
Hydraulic power
What is “trail” defined as?
TA is 6’ below the aircraft (10’ of POCL).
Automatic (remote) and Manual (RMCU) Hydraulic modes
- Normal dipping sonar operating modes
- Full capabilities
- Full safety features
