1. 406MHz ELT’s and 406MHz Antenna’s Presented by Lloyd Klee Aviation Safety Supplies Ltd.
NZHA Conference June 2016

2. Reasons as ELT to “failures”
Most Helicopter ELT failure to alert RCC are due to
Broken antenna (as it is on the outside of the aircraft)
Separation of BNC connectors on Coax Cable
Failure of the coax cable by earthing
Failure of the ELT to stay in the mounting bracket (Velcro strap separates or is loose)
Incorrectly mounted to allow G switch to activate
(many Artex ME406 mounted in AF configuration)
ELT not correctly encoded (factory maintenance code)
Fire
NZHA Conference June 2016

3. Slow Roll overs
Helicopter accidents in particular have a high failure of ELT systems generally due to broken antennas
Loss of control -slow roll overs will not activate an ELT even with multi axis G –Switches as the G-Switches are all the same specification and slow rollover sideway forces are always less than forward or vertical accident forces
NZHA Conference June 2016

4. Antenna Location
One of the major issues is the location of the Antenna
Many are installed on the side of the helicopter – Which side?
The side that the helicopter naturally lies on due the torsional rotation of the blades
NZHA Conference June 2016

5. Antenna Location The rest are on the top and just as vulnerable
NZHA Conference June 2016

6. Results of ELT location
Then there is the issue with the location of the ELT !
The main mast to the rotor can crush the ELT especially if it is a R22 or R44
NZHA Conference June 2016

7. Antenna Cables through bulkheads The new cable “stripper”
Passing Coax thru a bulk head is a nonsense
The Coax in this case earthed and no signal was receipted
NZHA Conference June 2016

8. Velcro straps that are not tight or suffer UV deterioration
Strap must be tight, I recommend replacement at battery time
Once again, no signal heard due to broken antenna
NZHA Conference June 2016

9. So what is to be done to improve installations ?
NZHA Conference June 2016

10. We have Tested an antenna within a Tail Boom – R44
NZHA Conference June 2016

11. Test of an antenna within a tail boom
Check BT
Power measured BT100 = 35.2dBm
Power receipted on GEO satellite =
dBm average
This test was with the ELT out in the open
NZHA Conference June 2016

12. Within Tail boom Test- (success)
 406AP- Vertical Antenna bent in “h” shaped to fit boom
then tail boom enclosed
Power measured on LEO satellite
dBm average
Satellite location correct
Latitude
longitude
This test was also successfully
repeated with a whip antenna
Horizontal within the tail boom
NZHA Conference June 2016

13. Testing on three separate occasions we have has proven
That a 406MHz antenna within an aircraft fuselage will transmit successfully to the Cospas-sarsat system
The tests show that it matters little if the fuselage material is composite or aluminium
i.e. You do not need a window
However NOTE that the signal will not transmit through a carbon fibre fuselage
NZHA Conference June 2016

14. The Issues
We needed to change some of the wording of the RTCA document D-204A
This is to do with antenna location
The word shall be needed to be replaced with should be
Current Wording DO-204A
Antenna Polarization The antenna shall be mounted to provide either right-hand circular or vertical polarization when the aircraft is in the normal flight attitude.
Actually most, if not all 406MHz ELT antennas are now omni directional
NZHA Conference June 2016

15. The Issues 3.1.10.4 Internal Antenna Location
The antenna shall / should be installed as close to the ELT unit as practicable, insulated from metal window casings and restrained from movement within the cabin area. The antenna shall / should be located such that its vertical extension is exposed to a RF transparent window.
The proximity to the vertical sides of the window and to the window pane and casing and the minimum acceptable window dimensions shall / should be in accordance with the equipment manufacturer’s instructions
This part of the regulation written around 121.5/243MHz ELTs
NZHA Conference June 2016

16. Results if wording change
Engineers will be able to install 406MHz ELT systems in the most crash worthy position & still comply with international regulations
ELT systems currently fail due to these same regulations that prevent ELT antennas being placed in a crashworthy position
NZHA Conference June 2016

17. Failure- Back to square one
Regretfully, and despite the evidence of the testing, I have failed to get the RTCA working group to change the wording.
The people within the group want surety of their documents. (NASA & others do not like the word should)
At this stage, it appears that the working group do not trust installers to use their judgement
They want rules that are black & white and not open to interpretation
NZHA Conference June 2016

18. CAA requested support
Following a request from me, the Director wrote to the chair of the WG and requested support for the research that I undertook
The group responded that they (including NASA) could not afford to re conduct the tests 1 (really?)
NZHA Conference June 2016

19. However in the meantime, PLEASE
Change the location of antenna to a crash worthy position
Check the Coax cable does not pass over fuselage joints or through metal bulkheads
Always ensure that there is some slack in the coax cable
Ensure all ELT installations are engineered and not installed as per the “book” because the NZ accident data clearly show that the “book” is wrong
NZHA Conference June 2016

20. However in the meantime
As of 10 June 2016, The NZ CAA have amended AC43-14 see
AC43-14 quote “Where an antenna is not installed in an approved location, suitable testing should be carried out to determine the suitability of the selected location.” 
AC43-14 also uses the word SHOULD BE for
Location 
Polarisation 
but still requires an electronic window for an internal antenna 
Thank you NZ CAA
NZHA Conference June 2016

21. Next generation Cospas-Sarsat 406MHz beacon systems to include
Mandatory GNSS specifications (GPS)
In-flight activation because of flight anomaly including Altitude, banking, depressurisation
ELT Power source options (rechargeable battery)
Increase ELT Crashworthy specifications
Return link services specifications options (SMS)?
Second generation homing? Possibly just 406MHz (although I am against that)
Improved Antenna and cabling specs incl. mandatory fire proof sleeves
Effectively a flight computer connected to the ELT providing inflight data for the ELT to act from
NZHA Conference June 2016

22. Next generation Cospas-Sarsat 406MHz beacon systems
RTCA are developing aviation-based 406 MHz MEOSAR distress alerting and location proposals for consideration by Cospas-sarsat.
Defining the frequency of transmission of data and applicable parameters- Rapid 406MHz pulses in the first few minutes
Can the MEOSAR cope with flight 1000Km/hr
Most importantly reduce the time for the first 406MHz burst to 5 seconds? (currently 50 seconds) & making GPS mandatory
NZHA Conference June 2016

23. The new MEOSAR system
Russia (SAR/GLONASS), USA (SAR/GPS) and ESA/EC (SAR/Galileo) working to include 406 MHz repeater instruments on future medium Earth altitude orbiting (MEO) GNSS satellite constellations
•Constellations will be fully compatible (72 Satellites)
• Global detection + location:
• Any beacon without embedded GPS - greater than Cospas-Sarsat accuracy with 3 bursts or less
• Self-locating beacons - GPS accuracy after single beacon burst
•Return Link Capability – May allow two messages
•Currently under in NZ
NZHA Conference June 2016

24. Existing C-S system vs MEOSAR
NZHA Conference June 2016

25. One Solution to ELT issues
As a commercial plug with a small apology 
You can OVERCOME many of the existing issues by
Installing a Kannad Integra which has a backup 406MHz antenna inside the actual ELT thereby overcoming two of the main failures
The Coax Cable and connectors
&
The Antenna breaking
& GPS
NZHA Conference June 2016

26. Also announced-10 year warranty
NZHA Conference June 2016

27. Summary
The NZ CAA has supported my involvement within the RTCA working group.
However the RTCA is, at this stage, not going to assist with a wording change
As I indicated previously, they want specifics not a generalisation. ( Shall vs Should)
HOWEVER with the new revision of AC43-14 the Director of NZCAA has given the installers an opportunity to save more lives with better ELT installations –
We all know about that golden hour
NZHA Conference June 2016

28. The Tui beer circle of life- yeh right
NZHA Conference June 2016

29. Questions ??
For any questions or comments on this presentation,
NZHA Conference June 2016