Load test ELT mount

[triple8s]

Whats the deal with ELT mounting. I at one time had an ELT mounted inside the baggage area and now getting a new ELT I hear of load testing the mount. I assume this is new ?

[N601RX]

The ACK E-04 406 mhz unit I installed specified a maximum amount of deflection when a given load is placed on the mounting member.

 

RTCA document DO-204 paragraph 3.1.8. prescribes the mounting requirements which
must be met when installing this ELT, these requirements are as follows:
The ELT shall be mounted to primary load-carrying structures such as trusses, bulkheads,
longerons, spars, or floor beams. (not aircraft skin.) The mounts shall have a maximum
static local deflection no greater than 2.5mm (0.1 inch) when a force of 450 newtons (100
lbs) is applied to the mount in the most flexible direction. Deflection measurements shall
2
be made with reference to another part of the airframe not less than 0.3 meter (1 foot) nor
more than 1.0 meter (3 feet) from the mounting location. After selecting a suitable location
meeting all of the above requirements. Drill and mount the ELT tray assembly as shown in
Fig 3. A doubler plate may be required. Secure latches with tie wrap as shown.

[M204ever]

Go with Service Instruction M20-116, .. no structural tests then, and, more important, approved data!

[danb35]

Why is approved data so important?  Installing an ELT isn't a major alteration, so it doesn't need approved data to support it.  OTOH, the Mooney SI does indicate where a suitable mounting place would be.