OAT requirement?

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JC150

Pre-takeoff checklist
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JC150
I have a PA28R which has the OAT gauge on the windshield. I am replacing the windshield currently as was wondering if I could legally get rid of the OAT gauge since I have the Aspen PFD which also has the temperature information on it? Thanks
 
I was faced with the same delima when I replaced all of the plexiglass in my Cherokee. I did not want another temperature probe sticking through the windshield. I installed this in my old Wakmann clock hole to replace my thermometer and clock. I love it. It is so easy to read and operate. The thermometer in the windshield was so hard to see and read. Best of luck with whatever you go with.

http://www.fdatasystems.com/gt-50
 

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For $160, that's probably the cheapest actual useful instrument out there.
 
Thanks. So Since I have the OAT on the Aspen already I guess I can ditch the one in the windshield.
 
Back to the title of this thread...

...is there anywhere a legal requirement for an OAT?

I don't recall one for either VFR or IFR, but I may be mistaken.
 
FastEddieB said:
Back to the title of this thread...

...is there anywhere a legal requirement for an OAT?

I don't recall one for either VFR or IFR, but I may be mistaken.
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I'm thinking it is required equipment for VFR... just thinking logically (TAS, Density Alt and performance, icing).
 
OAT is not in any of the required equipment lists, for VFR or IFR, day or night. But then again, neither is any specific navigation equipment. Much like navigation equipment, just because it isn't required doesn't make it practical.
 
As an aside, my Sky Arrow was shipped without an OAT gauge.

Due to the vagaries of S-LSA, before going Experimental, I could not have installed one without a Letter of Authorization from the manufacturer, often not easy or cheap to acquire.

Being Experimental made it not only easy, but cheap!

15676236960_c4eb54feb9_z.jpg
 
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TOMATO FLAMES
GRABCARDD
I don't see any requirement for an OAT gauge, although it would be good to have one IMO
 
If nothing else, it's nice to watch it go down as the altimeter slowly goes up in the summer.
 
jordane93 said:
TOMATO FLAMES
GRABCARDD
Click to expand...
I don't know what all those letters mean (does one o those T's stand for "temperature", or one of the O's for "OAT" :dunno:), but if you look in 91.205 in your FAR/AIM or on the FAA RGL Home page, you won't find an OAT gauge listed as a requirement for any flight mode -- day/night, VFR/IFR.
 
Day VFR:

T achometer
O oil pressure gauge
M anifold pressure gauge for each atmosphere engine
A irspeed indicator
T emperature gauge for each liquid cooled engine
O il temperature gauge


F uel level gauge
L anding gear position indicator
A ltimeter
M agnetic heading indicator
E mergency locator transmitter (ELT)
S eat belts


Night VFR Additional:

F uses
L anding lights
A nticollision lamps
P position indicator lamps
S ource of power
 
Pedals2Paddles said:
Day VFR:

T achometer
O oil pressure gauge
M anifold pressure gauge for each atmosphere engine
A irspeed indicator
T emperature gauge for each liquid cooled engine
O il temperature gauge


F uel level gauge
L anding gear position indicator
A ltimeter
M agnetic heading indicator
E mergency locator transmitter (ELT)
S eat belts


Night VFR Additional:

F uses
L anding lights
A nticollision lamps
P position indicator lamps
S ource of power
Click to expand...

WHOGAS?
 
Ron Levy said:
WHOGAS?
Click to expand...

Oh that is my new favorite response to tomato flames. Thanks ron!

My glider actually is required to have an OAT gauge when flying with water to ensure that the water doesn't freeze in the tanks.
 
Is adding a digital OAT and sensor to the side of my plane something I can legally install on my own or is this something I need to have done by a licensed avionics shop? Where do I find the ins-and-outs of what I can and can't do to my own airplane?
 
CherokeeGirl said:
Is adding a digital OAT and sensor to the side of my plane something I can legally install on my own or is this something I need to have done by a licensed avionics shop? Where do I find the ins-and-outs of what I can and can't do to my own airplane?
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That’s not preventative maint. You need an AP
 
Old thread.

But as seen upthread, my Amazon.com OAT gauge is still working fine 8 years on. I think I replaced the battery once.

I think if an owner were to Velcro a similar gauge somewhere and run the sensor to somewhere in the free air stream, I think it would be OK, so long as nothing was bolted in place or otherwise permanently mounted.
 
jordane93 said:
TOMATO FLAMES
GRABCARDD
I don't see any requirement for an OAT gauge, although it would be good to have one IMO
Click to expand...
The only place I know of: (Which admittedly doesn't apply to many of us.)

§ 125.205 Equipment requirements: Airplanes under IFR.
No person may operate an airplane under IFR unless it has -
(a) A vertical speed indicator;
(b) A free-air temperature indicator;
(c) A heated pitot tube for each airspeed indicator;
(d) A power failure warning device or vacuum indicator to show the power available for gyroscopic instruments from each power source;
(e) An alternate source of static pressure for the altimeter and the airspeed and vertical speed indicators;
(f) At least two generators each of which is on a separate engine, or which any combination of one-half of the total number are rated sufficiently to supply the electrical loads of all required instruments and equipment necessary for safe emergency operation of the airplane; and
(g) Two independent sources of energy (with means of selecting either), of which at least one is an engine-driven pump or generator, each of which is able to drive all gyroscopic instruments and installed so that failure of one instrument or source does not interfere with the energy supply to the remaining instruments or the other energy source. For the purposes of this paragraph, each engine-driven source of energy must be on a different engine.
(h) For the purposes of paragraph (f) of this section, a continuous inflight electrical load includes one that draws current continuously during flight, such as radio equipment, electrically driven instruments, and lights, but does not include occasional intermittent loads.
(i) An airspeed indicating system with heated pitot tube or equivalent means for preventing malfunctioning due to icing.
(j) A sensitive altimeter.
(k) instrument lights providing enough light to make each required instrument, switch, or similar instrument easily readable and installed so that the direct rays are shielded from the flight crewmembers' eyes and that no objectionable reflections are visible to them. There must be a means of controlling the intensity of illumination unless it is shown that nondimming instrument lights are satisfactory.
 
CherokeeGirl said:
Is adding a digital OAT and sensor to the side of my plane something I can legally install on my own or is this something I need to have done by a licensed avionics shop?
Click to expand...
Its considered an alteration and requires a mechanic sign off.
CherokeeGirl said:
Where do I find the ins-and-outs of what I can and can't do to my own airplane?
Click to expand...
Look to Part 43 Appx A(c) for a list of work categories you can perform under your pilot certificate. So long as the work fits into one of those 32 items and falls under the Part 1 definition of preventative mx you good to go. However, I'd recommend going over that list with a mechanic if you dont have a lot of experience with this and making the Part 43 entries.
 
My plane has an OAT guage in one of the wing vents. I've never used it for anything other than to satisfy my curiosity. What am i missing out on?
 
Lindberg said:
My plane has an OAT guage in one of the wing vents. I've never used it for anything other than to satisfy my curiosity. What am i missing out on?
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All depends on what kind of flying you do.

I wouldn’t want to be flying IFR in IMC without one.

On the other hand my T6 doesn’t have an OAT gauge and I’ve never missed it. If it feels cold, I close the canopy.
 
Lindberg said:
My plane has an OAT guage in one of the wing vents. I've never used it for anything other than to satisfy my curiosity. What am i missing out on?
Click to expand...

Well, clearly you live in the flatlands...probably in the south?
 
Lindberg said:
No. But I also don't know why I'd need to calculate TAS while I'm flying.
Click to expand...

I don’t think I’ve calculated my TAS in flight in the last 1000+ hours of flying.

Last time I did was when I had first gotten my Twin Beech and I wanted to see what my TAS was for cruise power settings. Haven’t done it since.
 
I like to calculate TAS to gauge whether forecast winds were accurate as a part of fuel planning on long XCs.
 
Lindberg said:
Don't you use ground speed for that?
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How can you tell wind speed from ground speed alone? You need both ground speed and TAS to determine the wind, as well as crab angle if you want to know more than the headwind (or tailwind) component. Wind makes ground speed different from TAS. If there’s zero wind, ground speed = TAS.

Modern electronics have largely made it unnecessary to calculate TAS, though. What we really care about for navigation is ground speed, which gives us the time to our next checkpoint and to our destination. EFBs and GPS do that for us. Still good to know how to do the calculations manually, of course, but seldom necessary.


EDITED - If you meant using ground speed to check fuel planning, not to determine winds, I agree with you.
 
kaiser said:
I like to calculate TAS to gauge whether forecast winds were accurate as a part of fuel planning on long XCs.
Click to expand...

Half Fast said:
How can you tell wind speed from ground speed alone?
Click to expand...

How can you tell wind speeds from TAS alone? ;) You can't. In flight, you'd need TAS, GS, and track to calculate wind velocity. But if you already know GS, there's no reason to go back to TAS for fuel calcs..... So even without GPS, when flying XC, you've never needed to know wind velocity or TAS to check your fuel planning, you just go by your time across your checkpoints. Calculating GS just requires a map and a watch, not a thermometer. :cool:
Expected TAS is needed for fuel planning on the ground, but only to combine with forecast winds to calculate expected GS. :D
 
I should have explained better. It’s more about measuring winds aloft and verifying accuracy of forecast/monitoring Wx trends in flight. Sure, TAS is just one input. But I’ve changed course and enroute fuel stops due to “actual winds aloft”.
 
kaiser said:
I should have explained better. It’s more about measuring winds aloft and verifying accuracy of forecast/monitoring Wx trends in flight. Sure, TAS is just one input. But I’ve changed course and enroute fuel stops due to “actual winds aloft”.
Click to expand...
How do you measure winds aloft by knowing TAS?
 
Lindberg said:
How can you tell wind speeds from TAS alone? ;) You can't. In flight, you'd need TAS, GS, and track to calculate wind velocity. But if you already know GS, there's no reason to go back to TAS for fuel calcs..... So even without GPS, when flying XC, you've never needed to know wind velocity or TAS to check your fuel planning, you just go by your time across your checkpoints. Calculating GS just requires a map and a watch, not a thermometer. :cool:
Expected TAS is needed for fuel planning on the ground, but only to combine with forecast winds to calculate expected GS. :D
Click to expand...
All true, except where you used the word “planning”. If you don’t know how your TAS compares to what you think it’s going to be, we call it “guessing”.
 
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