Bell 212/412 headset plug diameter

[Moemen Shahawy]

Hello,

I was having a debate about the headset plug diameter of the Bell 412 with a colleague, however no information regarding this matter was found in the pilot's manuals. I guess it would be mentioned in the tech. & maintenance manuals, but I don't have those.

So, 1. is the 412 headset plug is a U-174/U or a U-93A/U (TP120) plug ? I was told that the U-174/U is (7.1mm / 0.281in. diameter)

I believe that the U-174 is standard on most civilian helicopters, but I'm not sure, so I need clarification for that matter.

Also, 2. the 412 being a civilian helicopter that is developed from the 212 which has an original military variation (Huey), does it make its radios high impedance levels or low ones ? I am aware that the low impedance are for military and high for civilian, but I don't know if Bell brought the low levels from the Huey along with civilian variation or not considering other things were brought from the Huey to the 212.

Just need clarification as I'm new to this helicopter and still didn't get into every detail of it past the pilot's manuals.

Thank you.

[Gomer Pylot]

The jack is whatever is installed. You can put whatever plug you want on the cables. Every 412 I've flown has had standard jacks and standard civilian radios, high impedance. But anything can be installed, so nobody can tell you for sure what is in your helicopters.

[Troglodita]

Gomer is spot on!

High impedance is most common on the 412 but every now and then you will find a low impedance fit.

Bristow 212's in Nigeria in the old days were generally low impedance.

A switchable headset is the answer.

Same applies to the S76 fleet - no 2 seem to be identical in all respects!

Trog

[Good Vibs]

The size of the headset plug is 7.2mm diameter and 19.2 mm long.

[212man]

Also known as the 'US NATO' or 'UK NATO' question! Both can be found....,

[500e]

av_plug_main (http://www.mobileone.com.au/electro_acoustics/av_plug_main.html)

micl_main (http://www.mobileone.com.au/electro_acoustics/mic_main.html)

[Torquelimited]

The current Production 412EP is produced with a low impedance ICS although some are re-configured to a high impedance system as a customer option during customizing.