CALEDONIAN AIRBORNE SYSTEMS COMPONENT MAINTENANCE MANUAL CPT-900 AD/AF ELT System

Transcription

1 DESCRIPTION & OPERATION 1. GENERAL The CPT-900 Automatically Deployable/Automatic Fixed Emergency Locator Transmitter (AD/AF ELT) system (P/N /x) designed to be carried principally by helicopters involved in both maritime and land based operations, provides VHF (121.5MHz and 243MHz) homing, and UHF (406MHz) COSPAS-SARSAT satellite compatible transmissions. In the event of a forced or precautionary ditching in the maritime situation, the beacon can be deployed manually at the system control panel by the flight crew, or automatically when submersion is detected. The beacon is buoyant and self-righting for operation under extreme sea state conditions. When upright and floating in water, the transmitters are automatically activated. Activation can also be effected manually from the cockpit or locally at the beacon. The beacon reacts to the effects of wind, wave and current in a similar manner to survivors, liferafts, or floating wreckage, thus aiding rapid and effective search and rescue. In land based operations the CPT-900 beacon, while mounted within it's carrier on the aircraft, can be activated manually by the flight crew, or automatically by means of a carrier mounted G- switch. Manual activation can also be achieved by local control at the beacon. Generally, system readiness for deployment would be applicable when flight over water is undertaken, with readiness for activation applying for flight over land. However, no specific recommendations are made regarding the use of particular system operating modes for differing flight phases for which local flight safety regulations will prevail. 2. CPT-900 SYSTEM DESCRIPTION A. General The CPT-900 AD/AF ELT system consists of the CPT-900 beacon, a beacon carrier assembly and a cockpit control panel. The carrier contains the deployment and release mechanisms, a deployment battery, submersion actuator and g-switch. The control panel provides the means for manual deployment or activation of the beacon and an indication of deployment and activation status. Aircraft installation configurations normally include a pair of crash sensors (typically frangible switches) to provide for automatic deployment. During non-operational periods the system is disarmed by positioning the control panel arm and operate switches, and beacon arm switch to "OFF". Additional ground safety for maintenance personnel is provided for by means of a safety strap P/N positioned around the beacon shoulder and attached to the carrier. Should inadvertent deployment occur, this permits the beacon to move sufficiently to operate the "DEPLOYED" warning indicator, while preventing damage caused by full deployment. Figure 1 is a list of the CPT-900 system Leading Particulars. Leading particulars for the main unit subassemblies are contained within the appropriate texts. Figure 2 illustrates the CPT-900 Beacon fitted within the Carrier, Figure 3 shows the cockpit Control Panel, and Figure 4 is a functional block diagram of the CPT-900 system. Page 1

2 General: MOPS CALEDONIAN AIRBORNE SYSTEMS Characteristics Approval Classification ELT Class 2 Temperature Range: Operating -20 o C to + 55 o C Storage (short term) -55 o C to + 70 o C Altitude 35,000 feet maximum Activation Sensors: Submersion/Immersion: Fluid detector Tilt Switch Impact: G-switch (P/N /1) Performance ETSO-2C91a (RTCA/DO-183) ETSO-2C126 (EUROCAE ED_62) CS-ETSO Subpart A ETSO authorisation reference EASA.21O.259 Operates within 4-8 seconds of immersion Operating Angle 35 o ± 5 o from horizontal See Section 5E and Figure 10 for details Deployment Sensors: Frangible Switch (P/N or ) Submersion Actuator (P/N BC85-200) Page 2 See Section 7 and Figures 14 & 15 for details See Section 5A for details Beacon Battery: Configuration 4 series connected DD hermetically sealed lithium cells Cell Type Lithium Oxyhalide Electrochem 3PD0164-XA Open Circuit Voltage 15.6 ± 0.5 Vdc Rated Average Load Value 13.6 ± 1 25 o C Maximum continuous discharge current 3A Mean load Current < 140ma Beacon VHF/UHF Homing Transmitter: Carrier Frequency: VHF MHz ± 6KHz UHF 243 MHz ± 12KHz Duty Cycle 33-50% nominal Output Power (PERP) 180mW typical, 50mW minimum into a 50 ohm load at each carrier frequency throughout 50 hour period Emission Type A3A (RTCA/DO-183 classification A9) Modulation - audio tone Downward swept: 700Hz minimum in range 1600Hz (max) to 300 Hz (min) at 85%-100% amplitude modulation Modulation - Sweep Repetition Rate 2 Hz to 4 Hz Sideband components Symmetrical, clearly defined and distinct from carrier at both & 243 MHz. ELT spectrum At MHz: 30% of energy in a bandwidth of ±30Hz about the carrier frequency over the audio/sweep modulation cycle. Antenna Radiation Pattern At 243 MHz: 30% of energy in a bandwidth of ±60Hz. Omni directional (Vertical Polarization) Figure 1 - CPT-900 System Leading Particulars

3 Characteristics Performance Beacon Satellite Transmitter: Carrier Frequency MHz ±1kHz Repetition Period 50 seconds ± 5% Transmission delay One repetition period after activation before first distress transmission Power Output (EIRP) 2dBW minimum Continuous Transmission Protection limited to 45 seconds maximum Transmission Time: Total 440 milliseconds ± 1% Unmodulated Carrier Transmission 160 milliseconds ± 1% Digital Message 280 milliseconds ± 1% Message bps ±1% Encoding Biphase L Phase Modulation Deviation ±1.1±0.1 radians peak Protocols All aviation ELT protocols supported Programmable Features Country Code Aircraft registration No. Serial No. 24 bit aircraft address Aircraft operator designator Antenna Pattern Hemispherical (azimuth 360 o, elevation 5-60 o ) Polarisation Linear vertical Figure 1 - CPT-900 System Leading Particulars (cont.) Page 3

4 ENVIRONMENTAL CHARACTERISTICS SUMMARY Conditions Applicable Document / Para No. & Category Temperature Altitude RTCA DO-160B/4.0 Low Temperature RTCA DO-160B/4.5.1 Cat B2 RTCA DO-183/ a High Temperature RTCA DO-160B/4.5.3 Cat B2 RTCA DO-183/ Altitude RTCA DO-160B/4.6 Cat B2 Temperature Variation RTCA DO-160B/5.0 Cat A Humidity RTCA DO-160B/5.0 Cat A RTCA DO-183/2.3.3 Operational Shock & RTCA DO-183/ Crash Safety Vibration RTCA DO-183/2.3.5 Explosion RTCA DO-160B/9.0 Waterproofness RTCA DO-160B/10.0 Cat R Fluid Susceptibility RTCA DO-160B/11.0 Sand & Dust RTCA DO-160B/12.0 Fungus RTCA DO-160B/13.0 Impact RTCA DO-183/ Crush RTCA DO-183/ Salt Spray RTCA DO-160B/14.0 Cat S Power Input RTCA DO-160B/16.0 Voltage Spike RTCA DO-160B/17.0 AF Susceptibility RTCA DO-160B/18.0 Induced Signal RTCA DO-160B/20.0 Susceptibility Drop Test CAA Spec ft Submersion CAA Spec 16 50ft Buoyancy/Stability CAA Spec 16 Figure 1 - CPT-900 System Leading Particulars (cont.) Page 4

5 P/No. S/No. MOD. CARRIER FLANGE INSTALL THIS WAY Kg inc COUNTRY CODE ELT ID HEX CODE: CALEDONIAN ABERDEEN AIRBORNE SCOTLAND SYS TEMS Figure 2 - CPT-900 Beacon and Carrier Page 5

6 Figure 3 - CPT-900 Control Panel Page 6

7 insert Figure 4 (A3) Page 7

8 insert Figure 4 (A3) Page 8

9 B. Deployment CAUTION. To prevent inadvertent deployment it is essential that operators have a clear understanding of the functions of the cockpit control panel operating controls, particularly the distinction between those for activation and those for deployment; and also that maintenance procedures are rigidly adhered to. Release of the beacon is effected by electrically firing a cartridge/squib located within the Carrier mounted deployment mechanism. Deployment can be by both manual and automatic means. Automatic deployment occurs by operation of a crash sensor e.g. fuselage mounted frangible switch due to impact; or by operation of the Carrier mounted submersion actuator due to immersion in water. In the latter case power is provided to the squib from the integrated deployment battery, independent of other control and sensor circuits and aircraft power. Manual deployment is initiated from the cockpit Control Panel. Visual indication of deployment is provided to the flight crew by an annunciator at the control panel remaining continuously lit. The annunciator is fed from a carrier mounted microswitch which closes on ejection of the beacon. C. Activation Activation of transmission of an armed ELT can occur while remaining fixed on the aircraft, and also following deployment; and can be by manual or automatic means. Automatic activation occurs (regardless of the status of the remote control panel switches): Within 8 seconds of contact of the beacon with water following deployment When the beacon is not deployed, and a deceleration in excess of the carrier mounted g-switch threshold is sensed. Manual activation can be initiated: From the cockpit Control Panel Locally at the CPT-900 Beacon Visual indications of activation are provided by flash of the Control Panel annunciator, and illumination of the CPT-900 Beacon indicators. Ground crew alert of activation is provided by an audible sounder within the CPT-900 beacon radome. D. Inadvertent Activation CAUTION. The beacon must be activated only in an emergency. It is unlawful to transmit a distress signal unless an emergency exists. All steps possible must be taken to prevent inadvertent activation. These steps should include ensuring that operators have a clear understanding of the functions of local and remote controls and associated indicators; and that maintainers ensure correct adjustment of the carrier "deployed" microswitch. The 406MHz satellite transmitter is prevented from transmitting by one repetition period (approximately 50 seconds) to enable deactivation following inadvertent operation, to prevent alert of the emergency services. Transmission at the homing frequencies of 121.5MHz and 243MHz occurs immediately. E. Deactivation If beacon transmission is inadvertently initiated, or is detected by ground personnel, it can be halted either by reset at the cockpit Control Panel; or locally at the CPT-900 Beacon itself by reset or disarming. See 8. OPERATION for details. Page 9

10 Page 10 CALEDONIAN AIRBORNE SYSTEMS 3. CPT-900 BEACON ( Figure 5) A. General The CPT-900 Automatically Deployable/Automatic Fixed Emergency Locator Transmitter (AD/AF ELT) Beacon (P/N /X) covered by this manual is a self contained unit employing an emergency radio beacon homing transmitter operating on 121.5/243 MHz combined with a COSPAS/SARSAT compatible satellite transmitter operating on 406MHz. When activated, the beacon radiates a swept audio tone signal on the international distress frequencies of and 243MHz; and regular bursts of a unique digital message coded 406MHz signal. Once activated, the beacon will continue to transmit for at least 48 hours, or until deactivated. The beacon contains the VHF & UHF transmitters, their power management and activation circuits, and a power source; within a robust, impact withstanding but buoyant housing. Reprogramming of the 406MHz digital message and functional test can be carried out in-situ on the aircraft. In the event of detection of inadvertent activation either at the control panel or beacon annunciators, or operation of the beacon sounder, beacon transmission must be halted immediately. All local operating controls and indicators (protected within a switch guard) are mounted on the top of the radome which houses the combined MHz, 243 MHz & 406 MHz antenna system. A combined instruction and data label provides brief operating instructions; warnings regarding unlawful tampering and transmissions; and information regarding the beacon identification (including part number, serial number, and unique digital message content in the form of the COSPAS-SARSAT 15 bit hex ID code). A programming sensor enables reprogramming of the digital message when the protocol used requires this to be changed, for example on transfer of the beacon between aircraft etc. A calendar label provides an indication of the month and year at which time beacon battery change is due. The water sense electrode enables the presence of water to activate the beacon. The umbilical connector provides the interface for remote manual control from the cockpit Control Panel, automatic activation by the Carrier mounted g-switch, and the means to flash the Control Panel annunciator to indicate activation/transmission. Figure 5 also shows the principal beacon subassemblies. B. Beacon Controls The Beacon local controls and LED indicators enable manual activation, reset and indication of activation, in addition to responding to remote control from the cockpit Control Panel, and automatic activation by operation of the carrier mounted g-switch or internal water sensor circuit. On the ground the CPT-900 beacon can be turned on and off, activated, reset and tested locally using the front panel controls. Inadvertent CPT-900 Beacon turn off is avoided by the ARM switch being of the locking toggle type. Precautions must be taken to prevent operation or switch off by unauthorised personnel. C. Leading Particulars Beacon performance See Figure 1 (CPT-900 System Leading Particulars) Body Material Flame retardant heavy gauge polyethylene Body Colour International orange Lower Cap & Retainer Sleeve Material Nickel Plated Brass Dimensions See Figure 5 Weight (excluding Retainer Sleeve) 4.7kg Weight (including Retainer Sleeve) 4.9kg Umbilical Interface Connector Mates with carrier Umbilical cable

11 207mm diameter "XMT" LED OPERATE/FUNCTION SWITCH SWITCH GUARD PROGRAMMING SENSOR "PWR" LED DO E C CARRIER FLANGE INSTALL THIS WAY ATTENTION IT IS UNLAWFUL TO TRANSMIT A DISTRESS SIGNAL UNLESS AN EMERGENCY EXISTS. I E V NO T D T THIS BEACON WHEN ACTIVATED (IN XMT) TRANSMITS SIGNALS ON THE INTERNATIONAL DISTRESS FREQUENCIES MHz (A9) : 243MHz (A9) : MHZ (SHORT MESSAGE) E T Y OU C DEACTIVATION REMOVE FROM WATER HOLD 'XMT/RST' FOR 2-5 SECS ENSURE INDICATORS OFF ACTIVATION ACTIVATE ONLY IN AN EMERGENCY 'ARM' MUST BE SELECTED AUTOMATIC IN WATER WITHIN 8 SEC AUTOMATIC IN CARRIER BY G-SWITCH MANUAL FROM ACFT CONTROL PANEL MANUAL BY PRESS TO 'XMT/RST' F H S A TO DISABLE TRANSMISSION SET 'ARM' SWITCH TO OFF FLASHES IN 'XMT' & 'TST' XMT PWR ON FOR 'XMT' & 'TEST' 'XMT' & 'TEST' INHIBITED FOR SHIPPING / STORAGE OFF TST/RST PRESS FOR 'TEST' LIFT TOGGLE TO UNLOCK AUTO AUTOMATIC ACTIVATION OPERATING POSITION PRESS FOR MANUAL 'XMT' ARMED FOR XMT & TEST ARM XMT HOLD 'RST' FOR 2-5 SECS COSPAS-SARSAT APPROVED COUNTRY CODE AIRCRAFT No. HEX CODE: ETSO-2C91a & ETSO-2C126 CPT-900 AD/AF CLASS 2 ELT P/No S/No. A/R 4.9Kg inc. Sleeve MOD. BATTERY MAINTENANCE - REPLACEMENT DUE : UNIT CONTAINS LITHIUM BATTERY. OBSERVE WARNING MAINTENANCE MANUAL SAFETY PROCEDURES. CALEDONIAN AIRBORNE SYSTEMS ABERDEEN SCOTLAND CALENDAR LABEL "ARM" SWITCH INSTRUCTION & DATA LABEL LOCAL CONTROLS & MONITORS (SWITCH GUARD REMOVED FOR CLARITY) RADOME ANTENNA SYSTEM AUDIBLE SOUNDER UHF XMTR PRESSURE TEST POINT (BEHIND) 367mm UMBILICAL CONNECTOR WATER SENSE ELECTRODE POWER MANAGEMENT BOARD BATTERY COMPARTMENT VHF XMTR LOWER CAP RETAINER SLEEVE 83 mm 105mm diameter Figure 5 - CPT-900 Beacon (Post SB-04) Page 11

12 4. CARRIER (P/N /X) AND TYPICAL PLINTH (P/N ) A. General The Carrier (illustrated in Figure 6) consists of a glass fibre shroud and nose fairing, release mechanism (compression springs), and deployment mechanism. Also included are a submersion actuator, deployment battery, g-switch, deployed warning microswitch, and electrical cartridge contactor, described in more detail in 5. Carrier Components. Typically, the carrier will be mounted on the fuselage or tailboom, either directly or interfacing with a plinth (e.g. type as illustrated in Figure 7) which accommodates the aircraft skin contours. The carrier has several functions. 1. It supports and affords a degree of environmental protection to the beacon. 2. It contains the beacon against the compressed springs until deployed. 3. When deployment occurs, it directs the beacon downwards and rearwards away from the aircraft. 4. It contains the submersion actuator, deployment battery, g-switch and associated interwiring (see Figure 8) to provide maximum independence from aircraft power and wiring in the event of a crash. A microswitch which closes after deployment indicates this condition to the control panel annunciator (Note - Correct adjustment of the microswitch is critical in avoiding inadvertent activation). 5. Provision of electrical interface between the carrier components (as shown in Figure 8) the beacon umbilical connection, and the aircraft (via flying lead and carrier disconnect). When the aircraft is not at operational readiness, a safety strap P/N hooked to the carrier restrains the beacon and prevents damage and injury in the event of accidental beacon deployment on the ground. The carrier and plinth are supplied with primary fixing holes not predrilled. Refer to 7. Guidance For New Installations for drilling and suitable fixings information. B. Leading Particulars Length (Shroud) excluding Release Mechanism Length (Fairing) Width (Shroud) Width (Fairing) Height (Shroud) Height (Fairing) Carrier Assembly all up Weight Total Spring Force under compression Typical plinth ( ) weight Carrier Disconnect (typical) Mating Connector type 370 mm (in.) 115 mm (in.) 285 mm (in.) 145 mm (in.) mm (in.) mm (in.) 3.5 kg 310 lbf 1.8 kg MS3126E-12-10P MS3120E-12-10S Page 12

13 Figure 6 - Carrier Shroud & Fairing Figure 7 - Typical Plinth (Type ) Page 13

14 Figure 8 - Carrier Wiring Page 14

15 5. CARRIER COMPONENTS (See Figure 9) A. Submersion Actuator (P/N BC85-200) The submersion actuator consists of a plastic moulded base and body containing two nickel tubes connected to a 2 pin electrical connector at one end. Slots spaced along the body allow for the rapid entry of water to cover the tubes regardless of orientation, with the resulting contact firing the impulse cartridge and releasing the beacon. Fit to the carrier is by means of a U-bracket (P/N ). Pressing and turning counter-clockwise a removable plastic plug at the other end of the body enables access for periodic cleaning. Leading Particulars: Length Width Height Weight Response Time Mating Connector type mm (4.43 in.) 36 mm (1.42 in.) 36 mm (1.42 in.) 145 gms 0.5 seconds at 4 A / 1.5 seconds at 1.5 A MS3106E16S-4S B. Deployment battery (P/N ) The deployment battery fires the electrical cartridge in the deployment mechanism through operation of the submersion actuator. The battery consists of four lithium sulphur dioxide cells in series within a plastic housing with flying lead terminated in a 4-pin connector. Series and shunt diode protection, main fuse and thermal fuses prevent accidental charging and excess discharge. Leading Particulars: Length (excluding cable) Cable Length Width Height Weight Minimum No-load Voltage Nominal On-load Voltage Rated Capacity Duty Discharge Mating Connector 143 mm (5.63 in.) 320 mm (12.6 in.) approx. 80 mm (3.15 in.) 36 mm (1.42 in.) 260 gms Vdc 10.5 Vdc 3Ah at 100mA rate 4.1A into ohms for minimum of 10 milliseconds MS3120E8-4P C. Impulse Cartridge (P/N BC85-070) The cartridge is an electrically activated pyrotechnic squib which when supplied with sufficient current for a minimum period will sever a shear pin within the carrier deployment mechanism, enabling the carrier springs to release the beacon. This item requires careful handling. Transportation methods must comply with statutory requirements. Leading Particulars: Length Diameter Weight Net explosive content Resistance 13 mm (0.5 in.) 17.8 mm (0.7 in.) 2 gms 0.17 gms ohms Page 15

16 Absolute Maximum Safe Current Continuity Test Current Firing Current Operate Time Power Output Shelf Life Operational/Installed Life Interface Seal 1 A for 5 minutes (with subsequent performance degradation, and requirement for replacement) 10 ma recommended, 0.3 A absolute maximum 4.1 to 4.25 A for minimum of 10 milliseconds 15 milliseconds (from application of firing current) MPa ( PSI) into 5.5cm 3 volume 5 years (stored within supplied container) 1 year NAS A D. Deployment Mechanism (P/N ) The deployment mechanism which is part of the beacon release mechanism is described fully in 8. OPERATION. P1 Release Mechanism Submersion Actuator Cartridge Contactor Cap (Note. Not in final position) Deployment Battery G-Switch "Deployed" Microswitch Deployment Mechanism & Carrier Disconnect not shown Page 16 Figure 9 - Carrier Components

17 E. G-Switch (P/N /1) The multi-axis G-switch assembly comprises an orthogonal array of six crash sensors which when subject to crash deceleration provides a momentary ground via the umbilical interface to activate a beacon still resident within the carrier. Packaging is within an internally stiffened plastic housing, with electrical interface by 4-pin connector. Leading Particulars: Length (excluding connector) 73 mm (2.87 in.) Width 52.8 mm (2.08 in.) Height 39 mm (1.54 in.) Weight 230 gms Sensor Characteristics See Figure 10 Mating Connector type MIL (D38999/26WA-98SN) Figure 10 - G-Switch Response Curve (extract from EUROCAE ED-62) F. "Deployed" Microswitch The microswitch is located at the exit rim of the carrier and serves to detect the deployment of the beacon, and signal this by application of a ground to the Control Panel "D'PLYD" annunciator. Note that correct adjustment of this switch is crucial to both correct operation of the annunciator, and in the prevention of inadvertent activation of the beacon under conditions of high vibration or shock. Page 17

18 6. CONTROL PANEL (Figures 11 & 12) The cockpit located control panel (P/N /X) provides: 1. Remote manual activation, reset and indication of activation of the CPT-900 beacon 2. Remote manual deployment and indication of deployment status of the CPT-900 beacon 3. Control panel and deployment system self test 4. Ground safety (off) settings. Manual activation requires that the Arm switch be set to XMT ARM prior to momentarily setting the operate switch to XMT/RST position. Similarly manual deployment requires that the Arm switch be set to DPLY ARM prior to momentarily setting the operate switch to DEPLOY position. The prevention of inadvertent activation or deployment is ensured by both switches being of the locking toggle type, and by both being required to be set to the same setting. The press-to-test button, and D'PLYD/XMT, cartridge (SQUIB), frangible switch (FR), and deployment battery (BATTERY) annunciators provide for deployment system and panel self test. The central off positions provide for ground safety by ensuring that the deployment system is not armed, and remote manual activation is prevented. Beacon automatic activation can occur regardless of the status of the cockpit Control Panel, as long as the beacon is in the armed condition. For control panel switch and annunciator operating details see 8. OPERATION. 5V and 28V panel lighting options provide for night use. Note that control panels at Mod State "0" have in-service modified light plates, and Mod State "1" control panels replacement light plates with improved illumination. The control panel is a Dzus rail mounting panel with operating controls on the front face, and the 19-pin electrical interface connector mounted on the rear. A terminal strip provides for discrete component mounting and unit internal interconnections. Page 18 Leading Particulars: Figure 11 - Control Panel Illustration Width 146 mm (5.75 in.) Height 38.1 mm (1.5 in.) Depth 111 mm (4.375 in.) Weight 270 gms Panel Lighting Supply 5V at 300 ma - Variant /1 Mod State "0" 5V at 420 ma - Variant /1 Mod State "1" 28V at 120 ma - Variant /2 Mod State "0" 28V at 170 ma - Variant /2 Mod State "1" +28V at 25 ma - Variant /4 Mod State "0" +28V at 60 ma - Variant /4 Mod State "1" Mating Connector MS3126E-14-19S

19 Figure 12 - Control Panel Wiring (read in conjunction with Figure 4) Page 19

20 7. GUIDANCE FOR NEW INSTALLATIONS A. General Figure 13 shows typical CPT-900 system component locations. Page 20 Figure 13 - Typical System Component Locations B. Carrier & Plinth Installation The ADELT carrier must be located such that the beacon's ejection trajectory will not hazard the helicopter in any flight condition. It must not be located on moveable surfaces, nor in such a way that the helicopter flight or operating characteristics are adversely affected. Mounting holes are to be drilled in the carrier mounting flange at installation to suit the structure of each particular aircraft and i.a.w. the content of this manual. For specific aircraft types, reference must be made to the appropriate aircraft manufacturer's or operator's modification documents. Care should be taken in selecting a mounting point on the aircraft for the carrier. The positive rearward trajectory of the beacon, at velocities in excess of 8m/s relative to the aircraft, gives a wide selection of suitable mounting points. Release even in low speed autorotation will not hazard the rotors, as the beacon will always fall downwards and rearwards. The following should be considered in selecting a mounting point: a. The mounting point should be located on the opposite side of the fuselage to the tail rotor, or underneath the aircraft. b. Beacon trajectory should avoid radio aerials or other equipment. c. The carrier should not be located on or in close proximity to control surfaces, or in areas likely to affect the flight characteristics of the aircraft, and should be sufficiently remote from the effects of engine exhaust efflux. d. The carrier should be located in an area where there is minimal risk of direct lightning strike. e. Due to the possibility of gas venting from damaged Lithium batteries used within the beacon and carrier assembly, the equipment should not be installed in proximity to passengers or flight crew.

21 The carrier and plinth are supplied without primary fixing holes drilled. To satisfy stress requirements the following pattern of fixings has proved satisfactory: Number of carrier shroud fixings Number of carrier fairing fixings Number of plinth fixings Fixing size 8 minimum (centred within flange and equispaced as near as practicable to suit fuselage skin rivet placement) 2 minimum (centred within flange) 14 minimum (centred within flange and equispaced as near as practicable to suit fuselage skin rivet placement) 10-32UNF or M5 It is recommended that the plinth be set on the fuselage on a bed of RTV sealant, and that a 6.4 mm (0.25 in.) diameter hole be drilled at lowest point to allow moisture drainage. C. Structural Considerations The structure of the helicopter must be suitable at the intended mounting point. The combined weight of the beacon and carrier is 8.4Kg, and should ideally be secured to rigid formers or stringers. Where surface curvature prevents direct mounting, a plinth (e.g. P/N see Figure 7) may interface between shroud and aircraft skin. D. Crash Sensor (Deployment) Installation The position and alignment of the chosen crash sensors must be such as to ensure that a crash in any likely attitude will be detected. Automatic deployment of the beacon can be achieved by a variety of sensing devices which react in the event of an aircraft accident or controlled ditching in the sea. The exact type and number of devices and how they are arranged and electrically connected will vary between aircraft types. Careful references should be made to the applicable modification documents for the aircraft type involved. Several of the following can be included: 1. Frangible switches - located internally on the aircraft fuselage in close proximity to the aircraft skin in a susceptible area, these switches fracture under impact conditions and cause an electrical switch to close. 2. Inertia or 'G' switches - set to operate under high deceleration forces but not operational shocks. 3. Float switches -located externally beneath the helicopter's fuselage, these switches will operate in the event that the aircraft ditches into or lands on the sea. 4. Hydrostatic switches -set to operate at a present level of water pressure. These switches ensure the beacon is deployed even if the aircraft ditches and sinks rapidly beneath the surface. 5. Submersion actuators - operate when immersed in water. A typical minimal installation for a small to medium sized aircraft will consist of: 1. Frangible switches to deploy the beacon - quantity 2 off located internally on the aircraft fuselage in typical positions as indicated in Figure 13, and installed as shown in Figure 15. Figure 14 is an illustration of the recommended switch type. 2. Submersion actuators to deploy the beacon - quantity 1 off located within carrier Page 21

22 In the typical installation with the deployment battery and submersion actuator located within the carrier with the minimum of wiring, a high degree of protection during a crash sequence is provided as independence from other control and sensor circuits is achieved. This therefore provides a means of positive deployment in the event of:- a. Loss of the aircraft power supply. b. Defective, damaged or destroyed airframe wiring circuits. c. Failure of other crash sensors. d. The control panel switches being in the incorrect positions for deployment. E. General Notes on Installation of Wiring New wiring should follow existing cable runs where practical, be routed well clear of any moving parts such as rudder pedals and foot wells, with cognizance of HIRF considerations, and be secured i.a.w. standard practices for the aircraft type. Cables should be protected against chaffing by use of cable sheaths, clips and other suitable supporting devices. The squib firing line must be suitably screened. Page 22

23 P/N (with integral flying lead & protective sleeve) P/N Figure 14 - Frangible Switch Variants Typical Mounting Bracket Forward - P/N 07625D10514 Rear - P/N 07625D10515 Protective Sleeving (required with variant only) Frangible Switch (see Figure 13) Aircraft fuselage) 6mm internal clearance typically Figure 15 - Typical Frangible Switch Mounting Arrangement Page 23

24 8. OPERATION A. Release and Deployment Mechanism Operation The beacon is retained in the carrier by a deployment mechanism. The deployment mechanism consists of an open-ended retainer sleeve attached to the base of the beacon, and a main case held to the shroud face by a pair of split rings. The main case is hollow, with a shouldered, waisted-section piston within its bore. The piston is located in the locked position by a shear pin, which passes through the main case and piston. Two concentric coil springs are compressed between the beacon base and the release mechanism pressure plate. The pressure plate is fitted to the forward inner face of the shroud, An internal groove near the open end of the retainer sleeve accommodates four small locking spheres, which ride on the shouldered portion of the piston. The spheres are positioned so that they project through apertures in the main case. By bearing on the internal groove of the retainer sleeve, the spheres lock the beacon into the shroud. Release of the beacon is effected by electrically firing a cartridge located at the forward end of the maincase. The resulting gas pressure propels the piston along the bore of the maincase, breaking the shear pin. This allows the locking spheres to fall from the shouldered portion of the piston into the waisted section behind the shoulder, thus unlocking the retainer sleeve, which is attached to the base of the beacon. The beacon is then ejected by the coil springs. Travel of the piston within the release mechanism is restricted by a circlip inside the bore of the maincase. At ejection, the springs and main case remain secured in the shroud. After the beacon has been ejected, the microswitch on the side of the shroud closes and illuminates the "D'PLYD/XMT" annunciator on the control panel. Page 24 Figure 16 - Release & Deployment Mechanisms

25 B. Beacon Operation 1. General CALEDONIAN AIRBORNE SYSTEMS Activation of an armed beacon can occur by one of several methods. a. Local manual control by operation of beacon radome mounted toggle switches b. Remote manual control by operation of cockpit control panel toggle switches c. Automatically by water sense circuits detecting conductive path between main body electrode and lower cap indicating submersion in water d. Automatically by input sense circuit sensing momentary ground at umbilical connector on main body indicating operation of the carrier mounted g-switch. The beacon then provides simultaneous transmission on the international distress frequencies of and 243 MHz, and in addition on 406MHz for improved location and host aircraft identification by COSPAS-SARSAT satellites. When the CPT-900 beacon is activated, the homing transmitter is automatically started immediately, and the 406MHz satellite transmitter primed ready for first transmission after approximately 50 seconds. When the 406MHz encoded signal is received by a passing satellite, the data is transferred globally to a series of Local User Terminals (LUTs) and thence to the Search and Rescue (SAR) services via the COSPAS-SARSAT Mission Control Centre (MCC) network as depicted in Figure 17. Figure 4 contains a functional block diagram of the CPT-900 beacon. COSPAS-SARSAT SATELLITES SAR FORCES LUT-LOCAL USER TERMINAL MCC-MISSION CONTROL CENTRE RCC-RESCUE CO-ORDINATION CENTRE SAR-SEARCH AND RESCUE CPT-900 Figure MHz Transmission System Page 25

26 Page 26 CALEDONIAN AIRBORNE SYSTEMS 2. Abbreviated Operating Instructions Brief instruction for functional checks and operation of the beacon, environmental certification categories, and beacon data are contained within the combined instruction and data label attached to the radome face. The label content is illustrated in Figure Self Test Holding the beacon operate switch to the TST/RST position bypasses the normal power management circuits, and applies battery power directly to the transmitters. Correct beacon operation is indicated by a continuously lit green PWR indicator, a flashing amber XMT indicator, and accompanying audio tone.. Operation of the TST/RST switch does not result in a normal distress transmission, but causes the VHF/UHF transmitter output to be routed to an internal dummy load rather than to the antenna, and the 406MHz to output a single test coded message designed specifically not to alert the rescue services. The TST/RST switch position is also used to reset the beacon to terminate transmission (indicated by extinguishing of the green and amber indicators) after it has been deliberately or inadvertently triggered. The integrity of the beacon umbilical to control panel interface is checked by send of signal to flash the remote D'PLYD/XMT annunciator during self test. 4. Automatic Activation by Immersion When the CPT-900 beacon in the armed condition is stowed in the carrier on the aircraft, a tilt switch is held open, the battery disconnected, and the beacon is inoperative. When the beacon is deployed into water it floats upright due to the weight of the lower cap assembly, the tilt switch closes, the fluid detector operates and the power management circuit applies power to the beacon transmitters. At this time the green PWR indicator lights to indicate that power is applied. This is immediately followed by flash of the amber XMT indicator, and output of an audible tone to indicate that the transmitters are operating. Physically, one electrode of the fluid detector circuit is the machine screw located under the external buoyancy rim of the beacon casing. The other electrode is the metal base at the lower cap at bottom of the beacon which is connected to the battery common. A 4-8 second timer ensures continued beacon operation should the tilt switch momentarily open in a rough sea. The audio modulated homing distress signals (at carrier frequencies of and 243 MHz) and satellite signal (at 406MHz at 50 second intervals) from the transmitters are fed through a diplexer assembly to the common antenna system located within the beacon radome. The beacon will operate continuously for the specified required operating duration, or until it is deactivated either by disarming, or by removal from the water and manually reset. 5. Automatic Activation by Impact When the CPT-900 beacon in the armed condition is stowed in the carrier on the aircraft, an open circuit sensor contact holds the battery disconnected, and the beacon is inoperative. When the beacon umbilical input is subject to a momentary ground from the carrier mounted g-switch, the sensor circuit is set, and the power management circuit applies power to the transmitter circuits. Again the green PWR indicator lights to indicate that power is applied, with this immediately followed by flash of the amber XMT indicator, and output accompanying audible tone to indicate transmission. The umbilical connector located within the main body section of the beacon, connects to the g-switch via the beaconto-carrier umbilical. The beacon will operate continuously for the specified required operating duration, or until disarmed, or reset.

27 6. Local Manual Operation (at Beacon) CAUTION. The beacon must be reset following intended or inadvertent activation. If transmission is curtailed by setting the arm switch to the OFF position, the beacon will reactivate when the switch is returned to the ARM position, and must be reset immediately. Mounted at the centre of the CPT-900 beacon radome (see Figure 18) are the local controls for beacon arming, manual transmission activation, reset and self test; and annunciators providing indication of activation, transmission and self test result. CPT-900 Beacon switch types and functions ARM switch 2 position change over with locking toggle. To operate, the toggle must be lifted to unlock. Positions are: OFF ARM Operate/Function Switch Activation/transmission and test are inhibited. This mode is provided essentially for use during handling at installation & removal; for transportation & storage; and for emergency disabling following an inadvertent activation on the ground. Arms the CPT-900 beacon for transmission and test. Must be in this position at all times for operation - either locally, automatically or from the cockpit Control Panel. 3 position momentary action with central auto return position. Positions are: AUTO TST/RST XMT CPT-900 Beacon annunciators PWR XMT The central return position. When the ARM switch is at ARM the beacon will respond to cockpit Control Panel stimulus; or the carrier g-switch or internal water sensor circuit can automatically activate. When the ARM switch is at ARM, holding operate switch to this position will result in the beacon PWR indicator lighting, and self test with test result indication provided at the XMT annunciator and mimicked by the audible tone. When a beacon has already been activated (either from the Control Panel or locally) holding operate switch briefly to this position will result in beacon reset and transmission end. When the ARM switch is at ARM, setting operate switch momentarily to this position will result in beacon activation regardless of the status of the Control Panel switches. As a secondary feature, when a beacon has already been activated (either from the Control Panel or locally) holding the operate switch for 2-5 seconds to this position will result in beacon reset and transmission end in an identical manner to the XMT/RST switch at the Control Panel. Illuminates continuously when the beacon has been activated. Flashes on and off at 2 second rate when the CPT-900 Beacon has been activated and is transmitting. Also provides indication of the test status following beacon self test as follows: 2 second rate when BITE checks OK Off when UHF or VHF transmitter inoperative or power low Rapid flash when battery voltage low Audible tone Mimics the action of the XMT annunciator, primarily provided as alert to ground crew of inadvertent activation. Page 27

28 Power Indicator Arm Switch Beacon ID Details ETSO-2C91a & ETSO-2C126 DO-160D DO-160B Env Cat C2/A/YR/XRFDFSBXXXB COSPAS-SARSAT APPROVED CPT-900 AD/AF CLASS 2 ELT DIGITAL MESSAGE P/No COUNTRY CODE S/No. A/R 4.9Kg inc. Sleeve ELT ID MOD. HEX CODE: CALEDONIAN AIRBORNE SYSTEMS ABERDEEN SCOTLAND Programming sensor Transmission/BITE Indicator Operate/Function Switch Instruction & Data Label O D C E I O T N D E V T O T Y U IT IS UNLAWFUL TO TRANSMIT A DISTRESS SIGNAL UNLESS AN EMERGENCY EXISTS. THIS BEACON WHEN ACTIVATED (IN XMT) TRANSMITS SIGNALS ON THE INTERNATIONAL DISTRESS FREQUENCIES MHz (A9) : 243MHz (A9) : MHZ (SHORT MESSAGE) ACTIVATION C H A F E ACTIVATE ONLY IN AN EMERGENCY 'ARM' MUST BE SELECTED AUTOMATIC IN WATER WITHIN 8 SEC AUTOMATIC IN CARRIER BY G-SWITCH MANUAL FROM ACFT CONTROL PANEL MANUAL BY PRESS TO 'XMT/RST' S Beacon Battery Replacement Reminder ON FOR 'XMT' & 'TEST' PWR CARRIER FLANGE INSTALL THIS WAY ATTENTION DEACTIVATION REMOVE FROM WATER HOLD 'XMT/RST' FOR 2-5 SECS ENSURE INDICATORS OFF XMT TO DISABLE TRANSMISSION SET 'ARM' SWITCH TO OFF FLASHES IN 'XMT' & 'TST' 'XMT' & 'TEST' INHIBITED FOR SHIPPING / STORAGE LIFT TOGGLE TO UNLOCK OPERATING POSITION ARMED FOR XMT & TEST OFF ARM TST/RST AUTO XMT PRESS FOR TEST/RESET AUTOMATIC ACTIVATION PRESS FOR TRANSMIT BATTERY MAINTENANCE - REPLACEMENT DUE : WARNING UNIT CONTAINS LITHIUM BATTERY. OBSERVE MAINTENANCE MANUAL SAFETY PROCEDURES. COSPAS-SARSAT Digital Message Details Figure 18 - Beacon Controls, Indicators & Instruction Label Page 28

29 7. Remote Manual Operation (from Control Panel) CAUTION. It is essential that the panel arm switch be set to the correct position before engaging the DEPLOY or XMT/RST switch positions of the function switch. Failure to do so may result in inadvertent beacon deployment or activation. The cockpit control panel (Figure 19) enables remote control of beacon deployment or activation, display of deployment and activation status, and means for system component checks. As long the beacon is armed auto activation can occur regardless of the status of the control panel switches. CPT-900 Control Panel switch types and functions TEST ARM OFF DPLY ARM XMT ARM DEPLOY - XMT/RST (Operate) OFF DEPLOY Momentary press-to-test. When operated:- 1. "SQUIB" green L.E.D. will illuminate if the cartridge is connected. 2. "BATTERY" green L.E.D. will illuminate if the deployment battery is available. 3. "FR/SW" Red L.E.D. will illuminate if this indicator is serviceable. 4. "DPLY'D/XMT" annunciator will illuminate if this indicator is serviceable. 3 position change over with locking toggle and central off position. To operate, the toggle must be lifted to unlock. Positions are: Neither position of the operate switch is functional. The DEPLOY position only of the operate switch is functional. The network of deployment crash sensors is connected to the DC essential bus to provide automatic deployment should any of these operate, and crew initiated deployment is also possible. The XMT/RST position only of the operate switch is functional. 3 position momentary action with locking toggle and central return off position. To operate, the toggle must be lifted to unlock. Positions are: The CPT-900 Beacon can neither be deployed nor activated or reset from the Control Panel. However, automatic activation, and manual activation or reset locally at the beacon is possible. When the ARM switch is at DPLY ARM, setting operate switch momentarily to this position will result in beacon deployment. WARNING The beacon must not be deployed while the aircraft is on the ground, particularly in the presence of personnel in the vicinity of the aircraft. On the ground the beacon must be restrained with safety strap P/N or similar safety device in accordance with the aircraft manual. Page 29

30 XMT/RST Control Panel annunciator functions SQUIB BATTERY FR SW D PLYD/XMT When the ARM switch is at XMT ARM, setting operate switch momentarily to this position will result in beacon activation. Note that this function is also available at the CPT- 900 Beacon (regardless of the status of the Control Panel switches). When a beacon has already been activated, holding the operate switch for 2-5 seconds to this position will result in beacon reset and transmission end. Test indication only. Illuminates while the TEST button held depressed if the deployment squib/cartridge is installed, connected and serviceable. Test indication only. Illuminates while the TEST button held depressed if the deployment battery is available. Illuminates when a deployment crash sensor has operated, irrespective of the position of the ARM switch. Tested while the TEST button held depressed. A deployed confirmation light, illuminated continuously by the operation of the carrier deployed microswitch when the beacon has been deployed. Tested while the TEST button held depressed. Flashes on and off at 2 second rate when the CPT-900 Beacon has been activated and is transmitting. The integrity of the Control Unit to CPT-900 Beacon umbilical/ activation wiring is displayed using this annunciator during test. Page 30

31 Figure 19 - Control Panel Controls & Indicators Page 31

32 C. Beacon Reprogramming CALEDONIAN AIRBORNE SYSTEMS The beacon identity is normally factory programmed in the 406MHz transmitter digital message user-accessible data fields to an operator's definition, and in accordance with COSPAS-SARSAT requirements. The national authority for the country in which the beacon is to be registered will provide advice as to the appropriate country code and aviation user protocol applicable. Further information on beacon registration is available within COSPAS-SARSAT document C/S G.005 (available on-line at The Programmer/Test Set P/N (SPECIAL TOOLS, FIXTURES & EQUIPMENT Figure 902) is required for beacon reprogramming. The programmer enables message compilation and upload via an IR link to the programming sensor located on the beacon radome top face. Programming is preceded by a beacon self test. The beacon is safeguarded against erroneous programming /reprogramming unless the self test routine is completed satisfactorily. A detailed operating procedure is contained in MAINTENANCE AND TEST section 4I. The procedure must be correctly followed to ensure that inadvertent activation does not occur. Page 32