A new idea for ELT antenna placement

[jetdriven]

Originally Posted by Canadian_JOY

If you don't meet the FARs then your insurer will no doubt invalidate your insurance should an incident occur. You MUST use ONLY the antennas approved by the manufacturer, no substitutions allowed, period.

Can anyone provide an example of an insurer "invalidating" a policy because of some part not meeting the FAR's?

I have an ACK E-01 121.5 Mhz ELT. The new E-04 comes with an antenna that won't fit under the dorsal fin of our plane. Yet in the instructions, it says that you must use their antenna or one meeting the TSO. Turns our another brand does make a 406 whip antenna.

[Canadian_JOY]

Invalidation of insurance is certainly more common in the "certificated" world, but it has happened in the amateur-built world as well, particularly when dealing with unapproved modifications to engines and props. When there's a large liability suit at stake the insurance companies will do just about anything to avoid a payout.

With respect to antennas, please keep in mind that ELT manufacturers have to test their ELT as a complete "system" and as a result their TSO approval extends only to those components of the system which were tested together. You can't take an ACK antenna and use it on an Ameri-King ELT. In some instances the ELT manufacturer will list in their installation manual the part number of the antenna OEM so, if necessary, you can purchase the OEM part rather than buying the antenna from the ELT manufacturer, but this is not common practice. Listed below is information from the Kannad 406-AF Compact installation manual

KANNAD Designation Manufacturer KANNAD Part Number
ANT200 DAYTON GRANGER ELT 10-773-x 0145621
ANT300 CHELTON 1327-82 0124220
WHIP ANT AV200 RAMI AV-200 0146150
ROD ANT AV300 RAMI AV-300 0146151
ANT100(See note) PROCOM 0124206

[jetdriven]

Still, I never hear of insurance companies refusing to honor a claim, even when the owner messed up or the airplane is technically not airworthy. Not that they don't, but I cannot see a non-conforming antenna as a defense against payment.

According to ACK, you can use a different antenna with the E-04.
From their FAQ:
"Do I have to use the ACK antenna with my E-04 installation?
Yes, you have to use our antenna or a COSPAS/SARSAT / FAA TSO C-126 approved antenna meeting our VSWR requirements."

[az_gila]

Originally Posted by Canadian_JOY

Invalidation of insurance is certainly more common in the "certificated" world, but it has happened in the amateur-built world as well, particularly when dealing with unapproved modifications to engines and props. When there's a large liability suit at stake the insurance companies will do just about anything to avoid a payout.

With respect to antennas, please keep in mind that ELT manufacturers have to test their ELT as a complete "system" and as a result their TSO approval extends only to those components of the system which were tested together. You can't take an ACK antenna and use it on an Ameri-King ELT. In some instances the ELT manufacturer will list in their installation manual the part number of the antenna OEM so, if necessary, you can purchase the OEM part rather than buying the antenna from the ELT manufacturer, but this is not common practice. Listed below is information from the Kannad 406-AF Compact installation manual

KANNAD Designation Manufacturer KANNAD Part Number
ANT200 DAYTON GRANGER ELT 10-773-x 0145621
ANT300 CHELTON 1327-82 0124220
WHIP ANT AV200 RAMI AV-200 0146150
ROD ANT AV300 RAMI AV-300 0146151
ANT100(See note) PROCOM 0124206

From a FAA TSO point of view, substitution is allowed for an antenna IF it meets the manufacturer's electrical requirements, and the FAA requirements (ie, must be an aircraft antenna, not a bent piece of wire) -

http://rgl.faa.gov/Regulatory_and_Gu...H/ac20-41a.pdf

I would say an antenna change to another antenna that was designed for aircraft and met the published transmitters RF/electrical requirements would be a minor change per the AC above.

The SAR certification may be different though.

[bifft]

Originally Posted by cfiidon

I mounted mine in exactly the same spot, using a "rubber ducky" freq appropriate antenna. I use a piece of angle cut and shaped so as to provide a horizontal mounting plane.

Don

When you say "freq appropriate", did you measure the SWR on 121.5? I don't have the tools to do that, and don't have a beginning of a way to guess.

From the ACK E-04 manual it has:

Other antennas may be used provided they meet the
minimum VSWR requirements as noted in the specifications section of this manual, (Section 15) and meet COSPAS/SARSAT approval for use with the model E-04 ELT.

Section 15 has:

VSWR @ 121.5 MHz  2.0:1
VSWR @ 406 MHz  1.4:1

But then the COSPAS/SARSAT report only includes two antennas, the included 15 inch whip and a large blade that would be even harder to mount.

The extreme rear fuselage option isn't too bad, and aside from being right next to the vertical stab would be great. Probably better than having it inside the fuselage. I suppose that's the best of a bad lot.

I do like gereed's idea of having it inside a plastic tube to protect the canopy. That would be easy, not obstruct radio signals and you could replace the tube at any time. Need to think some more.

I'll look to see if I can find any COSPAS-SARSAT approved antennas that list the SWR measurements.

[jetdriven]

Try this. it fits the E-01 and E-04's requirements, without that stupid 8" rigid plastic section. To me, it sounds legal for an ACK E-04 install.
http://www.aircraftspruce.com/catalo...?clickkey=5356

[bifft]

Originally Posted by jetdriven

Try this. it fits the E-01 and E-04's requirements, without that stupid 8" rigid plastic section. To me, it sounds legal for an ACK E-04 install.
http://www.aircraftspruce.com/catalo...?clickkey=5356

at 13.75 it wouldn't fit under the canopy without bending, but being straight wouldn't lie directly along the VS if mounted at the rear. Thanks, will keep looking, but I do notice that none of the dual frequency antennas I find are 7 inches, probably a basic physics reason for that. (Although, I could probably fit a blade antenna back there, sideways. Expensive and would look really silly)

[AirbusPilot]

I have my ELT antenna under empenage fairing (AK-451), for year I was wondering if it works in that position. Some time ago I was cleaning the panel from my 8, inside my metal hangar with doors closed and I pushed ELT button by mistake and also didn't hear the alarm for 1 or 2 minutes

Ten minutes later my wife call me almost crying, someone from SAR call my house and said that my ELT was activated.

Now I know my ELT works and I promised my wife not to clean my panel again

[az_gila]

Originally Posted by AirbusPilot

I have my ELT antenna under empenage fairing (AK-451), for year I was wondering if it works in that position. Some time ago I was cleaning the panel from my 8, inside my metal hangar with doors closed and I pushed ELT button by mistake and also didn't hear the alarm for 1 or 2 minutes

Ten minutes later my wife call me almost crying, someone from SAR call my house and said that my ELT was activated.

Now I know my ELT works and I promised my wife not to clean my panel again

That installation would not meet the required US TSO.

From the ACK-451 manual

The antenna must be installed VERTICALLY (within ? 15o of the vertical plane is acceptable).

Again, a rule bending DAR would be needed....

[Mel]

It is not the responsibility of the DAR to see that TSOs are met.
That is the responsibility of the owner/operator.
Same goes for the transponder/altitude reporting system, lighting systems, etc.

It is the DARs responsibility to confirm that the aircraft meets 21.191(g).