Radio with Weak Transmit. Placard? Avionics Shop?

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Nate G

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Nate G
Hi All,

I have a KX 155A for COM 2 that receives fine for ATIS, but transmit is weak. Really only good for contacting ground. Do I need to placard it somehow like "receive only?" I feel like flagging it "INOP" wouldn't be right as it does have use for receiving weather. I have a GNS 430 on COM 1 that transmits/receives fine.

On a side note, I'm trying to find an avionics shop that is willing to diagnose the problem (antenna, cable, unit) and suggest a solution, but haven't had luck so far (too busy, don't have bench equipment, etc). Any suggestions? I'm in Reno, NV.

Thanks

Nate
 
Nate

You may have a failing antenna or cable to antenna. A failing antenna will receive but has trouble getting power out. I had a failing antenna cable that would receive for 50+ miles but transmit only around 100 yards.

Try swapping antenna cables between com 1 and com 2 to see if it follows the antenna.
Get a SWR meter and see what your SWR is during transmit.
 
FORANE said:
Nate

You may have a failing antenna or cable to antenna. A failing antenna will receive but has trouble getting power out. I had a failing antenna cable that would receive for 50+ miles but transmit only around 100 yards.

Try swapping antenna cables between com 1 and com 2 to see if it follows the antenna.
Get a SWR meter and see what your SWR is during transmit.
Click to expand...

:yeahthat:

Had a similar experience. Replaced the coax and the antena and it was like a new radio.
 
Why placard it… I see way too many of those stickers, plus unless you’re an A&P you can’t really inop something.
 
Skymac said:
plus unless you’re an A&P you can’t really inop something.
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FYI: a pilot can comply with 91.213(d) via a deactivation of the equipment. It can be as simple as turning it off or pulling a CB or anything that would fall under a preventative maintenance category. Outside of that you'll need an AP to take care of it.
 
Bell206 said:
FYI: a pilot can comply with 91.213(d) via a deactivation of the equipment. It can be as simple as turning it off or pulling a CB or anything that would fall under a preventative maintenance category. Outside of that you'll need an AP to take care of it.
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I think if you read AC91.67, Deactivation means to make a piece of equipment or an instrument unusable to the pilot/crew by preventing its operation. Simply turning something off is not a deactivation.
 
Clip4 said:
I think if you read AC91.67, Deactivation means to make a piece of equipment or an instrument unusable to the pilot/crew by preventing its operation. Simply turning something off is not a deactivation.
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AC 91-67 was cancelled a few years ago. But when it was valid reference it stated turning off the equipment was acceptable form of deactivation. There is another reference to this somewhere but I'm unable to locate it at present.
upload_2022-4-9_8-45-57.png
 
Part 91 requires the equipment to be deactivated or removed. Preventative maintenance does not contain a turn off your inop radio section.

k. Inoperative means,that a system and/or component has malfunctioned to the extent that it does not accomplish its intended purpose and/or is not consistently functioning normally within its approvedoperatinglimits or tolerances


g. Deactivation means to make a piece of equipment or an instrument unusable to the pilot/crew by preventingits operation.

u. Preventive Maintenance. The term preventivemaintenancerefersto simple or minor preservationoperationsand/orthereplacementof small standard parts not involving complex assembly. FAR Part 43, Appendix A(c), contains a list of preventive maintenanceitems.
Qualified mechanics or certificated pilots may accomplishpreventivemaintenanceand approve the aircraft for return to service
 
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...if a tree falls in the forest....
 
Clip4 said:
Part 91 requires the equipment to be deactivated or removed.
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So where does it state a pilot can not deactivate inoperative equipment per 91.213(d)? Pulling a CB or placarding a switch and making a write up are all within a pilot's cert.

upload_2022-4-9_14-26-50.png
 
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Clip4 said:
Part 43. Deactivation by pulling a breaker is not in preventative maintenance item.
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I believe Part 43 only applies to 91.213(d) when maintenance is performed. So pulling a CB is maintenance now? Or placarding a switch he turned off is maintenance? You may want to review 91.213(d) again as it is pretty ambiguous on deactivating equipment and by whom. Just as the cancelled AC was.
 
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Doug Reid said:
Got any friends who are active in amateur radio that can help you ?

Forane is on the right track :)
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I was thinking the same thing. They probably have an antenna analyzer that will quickly tell you where the problem is. 73
 
Bell206 said:
I believe Part 43 only applies to 91.213(d) when maintenance is performed. So pulling a CB is maintenance now? Or placarding a switch he turned off is maintenance? You may want to review 91.213(d) again as it is pretty ambiguous on deactivating equipment and by whom. Just as the cancelled AC was.
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The regulation applies to inoperative equipment. Inoperative equipment turned off is still inoperative equipment unless the aircraft has an MEL permitting the flight. If just turning it off was permissible, the FAA would not provide an MEL portion of the regulation, which does provide a method to just turn off and placard inop.
 
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Clip4 said:
Inoperative equipment turned off is still inoperative equipment unless the aircraft has an MEL permitting the flight.
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The point you’re missing is that the placard and logbook entry is what satisfies 91.213(d). Whether the equipment is deactivated or removed is simply a condition. So turning the system off, placarding that power switch, and making the logbook entry completes the 91.213(d) requirement. And while the AC was cancelled, the latest revision of Order 8900.1 basically states the same process as shown below. It further defines when a mechanic should be involved. Regardless, if you prefer not to follow this guidance that’s your decision as the owner/operator, however, pilots have been performing this type task in this manner for decades.
upload_2022-4-10_11-52-17.png

Clip4 said:
If just turning it off was permissible, the FAA would not provide an MEL portion of the regulation, which does provide a method to just turn off and placard inop.
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True. But 91.213(d) is only applicable to a specific group of small aircraft. All other aircraft require an MEL. So there is no real comparison. Its also the reason you don’t see MMELs for those small aircraft.
 
I flew for years with no radio in my plane and even into LAX with permission of the tower. Why is a radio required now?
 
  1. VFR Requirements. It is the responsibility of the pilot to ensure that ATC clearance or radio communication requirements are met prior to entry into Class B, Class C, or Class D airspace. The pilot retains this responsibility when receiving ATC radar advisories. (See 14 CFR Part 91.)
 
Nate G said:
Hi All,

I have a KX 155A for COM 2 that receives fine for ATIS, but transmit is weak. Really only good for contacting ground. Do I need to placard it somehow like "receive only?" I feel like flagging it "INOP" wouldn't be right as it does have use for receiving weather.
Click to expand...

Placard "Yell loud when using Com 2"
 
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