OAT probe

[Critter]

I am trying to get my outside air temp working properly, i have checked the gauge and bonding, however l cannot find the OAT probe.

could someone please give give me an insight to where the probe is?

'77' 201.

Thank you in advance

Chris

[Cruiser]

On the M20J model it could be mounted in third or fourth access plate outboard of the wheel well, check both wings most likely under the right wing.

[carusoam]

In '94 the OAT gauge is located as Tom is describing, but is notable to say it is a very small protuberance and black in color.

You need to be under it to see it.

Hope that helps...

Best regards,

-a-

[N201MKTurbo]

On my 77 it was under the left wing. I couldn't get it to work so I replaced it with a Davtron digital which works great. The probe mounted in the same hole as the factory probe.

[Critter]

Thanks guys, l shall check tomorrow. I did locate a pitot drain at the left leading edge wing root which I did not know about. Initially I thought that was the probe.

I hope I can get it working, otherwise I shall go down the Davtron path, though $400 for a OAT gauge is hard to justify.

[OR75]

on a 77'J, it is attached to a panel under the right wing (copilot side / door wing). it looks like a small nipple protruding down.

many look for it in the vent on the pilot side. the probe is supposed to be installed for a reading not disturbed by exhausts, prop wash, cabin heating, etc ...

from what i read, i believe an OAT install is considered a major item ( for an IFR plane) and will require a 337 form.

Any A&P / IA input on that ?

otherwise, i would love to replace my clock and OAT with 1 Davtron 803

[BillC]

As odd as it may be, a temperature gauge is NOT required for IFR flight.

[Awful_Charlie]

As odd as it may be, a temperature gauge is NOT required for IFR flight.

 

Not true!  Depends on the country of registration and where used, eg http://www.caa.co.uk/docs/33/CAP393.pdf Schedule 4 Item F - Required by all aircraft flying IFR in classes A B C D and E

[OR75]

For IFR flights , an OAT and a clock are required

[N201MKTurbo]

What is so hard about a 337?

[BillC]

Okayyy....... Let me clarify. To all the pilots flying "N" registered airplanes flying under FAR's. An OAT gauge is NOT required.

OR75-Yes, a clock is required.

[OR75]

IA vs A&P

[Critter]

ok, found it.

Just outboard of RH fuel tank, fwd. 

Now i just have to figure how to get the thing to work.   

IFR or not i still want to be able to work out my TAS

 

Thanks all

[Awqward]

My plane had the OAT replaced just before I bought it. It was placed on the LHS of the fuselage just fwd of the leading edge....so it sticks out sideways....not sure why they didn't put it under the right wing where the old probe (still is)....I did a search of CAR3, FAR Part 23, part 91 and the M20 TCDS and I cannot find a requirement for an OAT probe, IFR or otherwise......however IMO it is still a Major Alteration requiring a 337 and IA....(and an STC).....so I'm still chasing this down with the previous owner as the paperwork is not quite right yet....a major hassle dealing with a French previous owner and the French shop and French IA who is rarely in the country!

[N201MKTurbo]

It was placed on the LHS of the fuselage just fwd of the leading edge....so it sticks out sideways....not sure why they didn't put it under the right wing where the old probe (still is)..

 

Easier wiring, lazy mechanic.

[OR75]

My plane had the OAT replaced just before I bought it. It was placed on the LHS of the fuselage just fwd of the leading edge....so it sticks out sideways....not sure why they didn't put it under the right wing where the old probe (still is)....I did a search of CAR3, FAR Part 23, part 91 and the M20 TCDS and I cannot find a requirement for an OAT probe, IFR or otherwise......however IMO it is still a Major Alteration requiring a 337 and IA....(and an STC).....so I'm still chasing this down with the previous owner as the paperwork is not quite right yet....a major hassle dealing with a French previous owner and the French shop and French IA who is rarely in the country!

the requirement for OAT is in the POH. you should find a page with 4 columns for the requirements for VFR day, VFR night, IFR day and IFR night.

the OAT requirement has a note associated with it indicating " when required buy regulations" - i guess country specific.

[N201MKTurbo]

FWIW

 

I wont fly IFR without a working OAT.

[Mooneymite]

I always know what the outside air temperature is.....I don't need no stinkin' gauge!

[Awqward]

FWIW

I wont fly IFR without a working OAT.

[Awqward]

Me either....

[KSMooniac]

And especially an accurate one!  I'd like to know if it is 31 dF or 35 dF before entering that cloud or precip...

 

It isn't difficult to put the probes in the proper location under the wing, so don't settle for one exposed to sunlight, engine heat, etc.

[N201MKTurbo]

As soon as my Davtron clicks over to +1 the ice starts to melt....

[carusoam]

Time to go digital...

I still have a few analog devices.

-a-

[jetdriven]

My plane had the OAT replaced just before I bought it. It was placed on the LHS of the fuselage just fwd of the leading edge....so it sticks out sideways....not sure why they didn't put it under the right wing where the old probe (still is)....I did a search of CAR3, FAR Part 23, part 91 and the M20 TCDS and I cannot find a requirement for an OAT probe, IFR or otherwise......however IMO it is still a Major Alteration requiring a 337 and IA....(and an STC).....so I'm still chasing this down with the previous owner as the paperwork is not quite right yet....a major hassle dealing with a French previous owner and the French shop and French IA who is rarely in the country!

Its not a major alteration, and we installed ours as a log entry (minor alteration) with guidance from Davtron:

 

"Davtron Inc has determined that installation of all Davtron products are considered minor according to (FAR) 21.93(a).  All of our units are similar in design, with their electrical, mounting size, and weight being similar.  Even though we consider installation of Davtron products to be minor, it is up to the installing mechanic to determine if the installation is minor or major.  For a minor, a maintenance log book entry is all that is required.   The FAA has determined that the installation of replacement clocks in non-transport category airplanes is considered to be minor, therefore only a maintenance log book entry is required referencing letter 100S-GA-10-53 from the FAA."

[larryb]

Here's something I've wondered for a while. Lets say you want that new Davtron OAT installed. One mechanic says it's a 337. So you shop around, find another guy who says a logbook entry is fine. You go ahead and get it installed and signed off. Now, is it a done deal? Or can some IA at some future annual say "Where's your 337 on that nifty OAT you've got?"