Date post: | 17-Dec-2015 |
Category: |
Documents |
Upload: | lee-barnett |
View: | 216 times |
Download: | 1 times |
EPIRB’sHow They Work
&DF-430
On the C-130H
January 2010
How the System Works
L Yarbrough/D7 CFVS
LEOSAR & GEOSAR Satellites
L Yarbrough/D7 CFVS
Types of Beacons
• EPIRBs
406 MHz (w/ 121.5 homer)
Automatic activation when out of bracket and wet.
Floats upright to transmit
Strobe light
Min 48 hour transmit
Some GPS enabled
Maritime Distress Beacon
L Yarbrough/D7 CFVS
Types of Beacons
• PLBs406 MHz (w/ 121.5 homer)Manual activationCarried on persons May or may not floatHeld out of water to transmitNO Strobe light requiredMin 24 hour transmit Some GPS Enabled
Distress Beacon for Personal Use (Land Rescue)
L Yarbrough/D7 CFVS
Types of Beacons
• ELTs
Transmit on 121.5 (most) or 406 MHz
Integrated 121.5 MHz homerCrash activation
Floats upright to transmit
No Strobe light
Min 48 hour transmit
Aviation Distress Beacon
L Yarbrough/D7 CFVS
EPIRB
• Maritime Satellite
• Emergency
• Position-Indicating
• RadioBeacon
L Yarbrough/D7 CFVS
EPIRB Operational Requirements• EPIRB 406 MHz Signal - 5 Watts• Short bursts at approximately 50 second
intervals (varies between 47.5 and 52.5 s), with a transmission time of 440 ms or 520 ms.
• Transmits in the 406.0 to 406.1 MHz band.• Transmission consists:
– unmodulated carrier, for 160 ms,– short synchronization signal, signal inverted for test,– Digital message that provides stored information
(identification, nationality, type of user),– Optionally, current information like, type of emergency
and estimated location.
Designed to prevent inadvertent activation
L Yarbrough/D7 CFVS
Hex ID• EPIRB’s identification, when decoded into
its 15 character hexadecimal representation, which is the EPIRB’s unique identifier number.
• http://www.cospas-sarsat.org/Beacons/decode.htm
• Normally readout in 3 groups of 5 characters. Example: ABCDE 12345 ABCDE
L Yarbrough/D7 CFVS
Battery Replacement• Required at Expiration date or if EPIRB
activated for any reason besides test.
• Useful Life = power for all required testing + 48 hrs operation.
L Yarbrough/D7 CFVS
EPIRB Operational Requirements
• Positive visual and/or audible indication that EPIRB is activated (strobe light flashing).
• Easily manually deployed, activate, and deactivated, and transferred to survival craft.
• Not be activated or deactivated by conditions encountered in maritime environment.
L Yarbrough/D7 CFVS
EPIRB Control
• Ready – EPIRB should be ON in the water unless in its bracket. Sometimes labeled “OFF”.
• ON – EPIRB operates regardless of location or orientation. Unconditional “ON” position. (Requires two physical actions)
• Test – Self-test Function.
L Yarbrough/D7 CFVS
Prevention of Inadvertent Activation
• Must be fitted with means to prevent inadvertent activation and deactivation.
• Not automatically activate when water washes over while in bracket.
• Most EPIRBs use bracket with magnet to disable activation circuit.
L Yarbrough/D7 CFVS
EPIRB Deactivation
• Remove beacon from water and dry off or replace in bracket
• Move switch to OFF or Ready position
• If the above failed then: – Remove cover and disconnect battery
L Yarbrough/D7 CFVS
EPIRB Activation
• How– By definition it transmits:
• out of bracket and wet,
• by manual switch, in or out of bracket,
Or– Self test
L Yarbrough/D7 CFVS
EPIRB Activation
• What Happens;– Beacon starts transmitting its Unique
Hex ID in a 406 MHz digital message,
– 121.5 MHz homer with an audible warble,
– Strobe Light starts flashing.
L Yarbrough/D7 CFVS
Rockwell Collins DF-430
DF-430 Bearings
• Bearing are relative– (Heads up, not compass).
• Bearing Accuracy – less than 3°
• Bearing Stability - +/- 5° (means less needle swing, a more stable point)
• Bearing Range – continuous 360°
L Yarbrough/D7 CFVS
Bearing Inhibit
• Bearing Inhibit – during on-board transmission, the bearing computation is frozen (DF LOCK is displayed during on-board transmissions)
L Yarbrough/D7 CFVS
SLDMBs
• ARGOS (401.650) is the frequency for your SLDMB.
L Yarbrough/D7 CFVS
DF Bearing Pointer
• DF pointer only updates on receipt of next 406 MHz EPIRB burst transmission.
– Will seem jerky.
• EPIRB transmission only every ~50 sec.
• Burst transmission only half sec duration.
L Yarbrough/D7 CFVS
Figure-of-Merit (FOM) Values
• DF-430 will display a FOM value in range of 0-255.
• Practical application is as a secondary level of confidence the aircraft is tracking towards target.
L Yarbrough/D7 CFVS
406 MHz Detection Range
Altitude (ft)Detection
Range (nm)
25,000 133
22,500 129
20,000 124
17,500 119
15,000 113
12,500 106
10,000 99
7,500 88
5,000 76
2,500 57
1,500 23
L Yarbrough/D7 CFVS
Operational Considerations
• Transit in SAR Scan, unless tasking indicates a need to monitor a tactical freq.
• Greatest range/ earliest detection opportunity at higher altitudes.
• If a 406 signal is detected, DF needle will point.
L Yarbrough/D7 CFVS
406 Beacon Tests• Every 406 MHz Beacon is supposed to be
tested (using the self-test function) once every month.
• Each test transmits one live 406 burst.
• Wait at least two bursts before you react to a 406 Det.
L Yarbrough/D7 CFVS
EPIRB Prosecution
What Does the CC/RCC
do with a 406 Alert?
Registered/Unlocated 406MHZ EPIRB
• 1. RCC or RSC on receipt of unlocated registered 406 EPIRB:– a. Place case in the DISTRESS phase.– b. Assume SMC.– c. Determine status of vessel from contact
number listed, available databases, etc.
L Yarbrough/D7 CFVS
Registered/Unlocated 406MHZ EPIRB (cont)
• 2. If vessel is determined to be safe underway or in port:– a. Close case. A case will be claimed for all
406 alerts prosecuted
L Yarbrough/D7 CFVS
Registered/Unlocated 406MHZ EPIRB (cont)
• 3. If vessel is underway and cannot be contacted:– a. Issue UMIB for Home Port and general
area in which vessel is believed to be operating.
– b. Contact AMVER Ships and request callouts for the vessel.
– c. Contact USMCC and request satellite forecast for the geographic area.
L Yarbrough/D7 CFVS
Registered/Unlocated 406MHZ EPIRB (cont)
• 3. If vessel is underway and cannot be contacted:– d. If the next forecast satellite pass does not
locate the beacon consider sending an SRU to the area to attempt to hail the vessel or DF on 406/121.5MHZ homing signal. Continue investigating to try to determine last known position/probable track of vessel for additional searches.
L Yarbrough/D7 CFVS
Registered/Unlocated 406MHZ EPIRB (cont)
• 3. If vessel is underway and cannot be contacted:– e. If vessel cannot be located after reasonable
search is conducted, search will be suspended.
L Yarbrough/D7 CFVS
Registered/Unlocated 406MHZ EPIRB (cont)
• 4. If SRU is tasked to search for vessel:– a. Proceed to LKP/tasked search area. Make
callouts for vessel and attempt to DF homing beacon on 406/121.5MHZ.
L Yarbrough/D7 CFVS
Registered/Unlocated 406MHZ EPIRB (cont)
• 4. If SRU is tasked to search for vessel:– b. If signal cannot be DF’d once on scene and
unless otherwise tasked, aircraft shall complete a VS search at radius of 12NM. Vessels shall complete the same search at 3NM.
L Yarbrough/D7 CFVS
“A” solution located 406MHZ EPIRB
• 1. RCC or RSC on receipt “A” solution located 406MHZ EPIRB:– a. Place case in the DISTRESS phase.– b. Assumed SMC. – c. Determine status of vessel from contact
number listed (if registered), available databases, etc.
L Yarbrough/D7 CFVS
“A” solution located 406MHZ EPIRB (cont)
• 2. RCC or RSC if vessel is determined to be safe/underway or in port:– a. Close case.
L Yarbrough/D7 CFVS
“A” solution located 406MHZ EPIRB (cont)
• 3. RCC or RSC if vessel is underway and cannot be contacted:– a. Issue UMIB for general area in which
vessel is believed to be operating.– b. Contact AMVER ships in vicinity and
request callouts for vessel.– c. Dispatch SRU to located vessel and
determine status. SRU’s should be tasked to DF on the signal.
L Yarbrough/D7 CFVS
“A” solution located 406MHZ EPIRB (cont)
• 3. RCC or RSC if vessel is underway and cannot be contacted:– d. If vessel cannot be located after reasonable
search is conducted, search will be suspended.
L Yarbrough/D7 CFVS
“A” solution located 406MHZ EPIRB (cont)
• 4. SRU if tasked to search for vessel:– a. Proceed to position/tasked search area.
Make callouts for vessel and attempt to DF homing beacon on 406/121.5MHZ.
– b. If a signal cannot be DF’d once on scene and unless otherwise tasked, aircraft shall complete a VS search at radius of 12NM. Vessels shall complete the same search at 3NM.
L Yarbrough/D7 CFVS
“B” solution with alert probability less than or equal to 20%
1. RCC or RSC on receipt “B” solution with probability less than or equal to 20%:
a. Place case in the UNCERTAINTY phase.
b. Assume SMC.
c. Coordinate investigation with RCC responsible for “A” solution. If investigation determines “B” solution is the likely position, respond in same manner as an “A” solution.
L Yarbrough/D7 CFVS
“B” solution with alert probability greater than 20%
• 1. RCC or RSC on receipt “B” solution with probability greater than 20%:– a. Place case in the ALERT phase.– b. Assumed SMC.– c. Coordinate investigation with RCC
responsible for “A” solution. If investigation determines “B” solution is the likely position, respond in same manner as an “A” solution.
L Yarbrough/D7 CFVS
Unregistered/Unlocated EPIRB alerts:
• 1. RCC or RSC investigate identity of vessel through vessel data bases.
• 2. RCC or RSC contact RCC country of vessel registered and attempt to determine vessel’s status.
L Yarbrough/D7 CFVS
False Alerts
False Alerts
• If a false alert is determined upon arrival on-scene complete the following actions:– Have vessel de-activate the beacon.– Have vessel provide the beacon “HexID”– Have vessel provide the reason beacon
alerted and include in MISLE Reporting.– Advise vessel that EPIRB and bracket require
servicing and battery replacement.– Relay to tasking authority as required.
L Yarbrough/D7 CFVS
Operator Induced False Alerts
• 10% were Testing without following manufactures instructions, or other deliberate non-emergency activations
• 6% were EPIRBs deliberately taken out of bracket and naked of any control of the wet sensor.
L Yarbrough/D7 CFVS
EPIRB False Alerts
69% Caused by Failure of “The bracket decoupling function” to control the EPIRB–Manufactures, makes and models
in the US registration data base were proportionally represented by False Alerts
L Yarbrough/D7 CFVS
Why didn’t I get a 406 Detection or
How Long do False Alerts Last?
105 36 20 12 9 2 48
45.3%
60.8%69.4% 74.6% 78.4% 79.3%
100.0%
0
20
40
60
80
100
120
10 20 30 40 50 60 More
Alert Duration (in minutes)
Nu
mb
er
of
Ale
rts
L Yarbrough/D7 CFVS