Ammeter - Required?

[Bennett]

Always looking for panel space. The JPI 830 reports Voltage, and the annunciator

will light for low or high Voltage. I do have the factory Ammeter (2 1/4" hole)

in the upper left side of the panel, next to the ASI. This would be a great

place for an AOA indicator, so my question is: Is an Ammeter required equipment

for a M20J? Thank you for whatever authoritative information you can give me.

Much appreciated. Yes, I know an Ammeter gives you information that is different from a Voltmeter, but if an alternator fails, Voltage will drop.

[Mooneymite]

Always looking for panel space. The JPI 830 reports Voltage, and the annunciator

will light for low or high Voltage. I do have the factory Ammeter (2 1/4" hole)

in the upper left side of the panel, next to the ASI. This would be a great

place for an AOA indicator, so my question is: Is an Ammeter required equipment

for a M20J? Thank you for whatever authoritative information you can give me.

Much appreciated. Yes, I know an Ammeter gives you information that is different from a Voltmeter, but if an alternator fails, Voltage will drop.

 

Check your POH.

 

It is not listed as "Required Equipment" in my POH.  However, it depends on what the POH specific to your aircraft says.

[Bennett]

Along these lines, I also have a combination EGT/OT gauge on the left side of my panel. Both EGT and OT

are reported by the JPI 830. I seem to recall that the model 830 cannot be primary for EGT/OT. Is this

true? I would install the 930, except the fact it is larger, and my 830 is flush mounted without

additional room to flush mount the 930. Wish JPI would have understood how important it is to keep the

boxes uniform in size.

[Bennett]

Mooneymite, Thank you for your reply. I've gone through my POH several times, and I cannot find a

"Required Equipment" listing. I do find an Equipment listing with check marks for items that can be

installed, but there is no Ammeter shown on that list. The POH does talk about how the Ammeter functions,and shows an Ammeter in their graphic panel depiction. Hence my question: "Is an Ammeter required?"

[Mooneymite]

Hmmmm.  My POH is probably older than yours and includes a "required equipment list" for VFR and IFR ops.  Strange that yours does not.  The minimum equipment list is almost always part of modern aircraft POH's.  Perhaps it is listed elsewhere?

[Bennett]

Dang! I lost my reply again. I looked up a generic POH on the web, and it shows a Section II,

Limitations, and that an alternator load indicator (Ammeter) is shown as required for Day/Night/VFR/IFR

operations. My POH has a section II, Limitations, but does NOT contain a page showing "Required

Equipment" for these categories. Strange! I will have to check into this further. 1983 M20J POH for me.

[N601RX]

According to the sales brochure the EGT is optional on my F and I don't use it anyway because I have a JPI 830 also.  I will probably remove it when I need room to add something else.

 

Aerospace logics also has some nice 2 in 1 and 3 in 1 gauges that might buy you some panel space.

[Cruiser]

Bennett,

 

I just looked in a 1984 M20J POH and none of the instruments you mention are listed as required.

[Marauder]

Bennett -- the EGT is definitely not primary or required. I removed mine when I recently upgraded the engine analyzer to the 830.

[201er]

I'm pretty sure the EGT/OT is not required. It's even less useful than the ammeter because you have the exact same information but better coming from the 830. That's why I had the factory EGT/OT removed to make room for a Century IIb mode selector knob. By moving my clock over to the EGT/OT space, I was able to get the Century IIb selector away from under the copilot side of panel (horrible placement before). I'd definitely dump the factory EGT/OT before the ammeter. But that would be next on the list to go if there was something more useful to put in its place.

[201er]

I don't think EGT or OAT are required equipment though. So there is no "primary" or not. I didn't see it listed on the TCDS or in the POH. Nor it is required equipment for VFR/IFR operations. Same goes for ammeter.

 

What you may be confusing this with is the cluster gauges. For example the factory Oil Temp gauge is primary and cannot be replaced by the 830 as it is advisory only. Yet the factory fuel pressure and cht gauge can be placarded inop as they are not required instruments. Who can validate this?

[Bennett]

Thanks everyone. From the replies you can see why I asked the question. If LASAR agrees, I will dump my combination EGT/OT gauge (which I never look at since I use the JPI for that information) and put the Ammeter in that hole. That will leave a 2 1/4 inch hole next to ASI, where I will (probably) mount an AOA indicator if I can be convinced by Alpha (at Oshkosh) that it can be calibrated for my Mooney.

[larryb]

I thought all required equipment was listed in the type certificate? I just checked, I see no mention of egt/oat/clock/ammeter in the type certificate.

 

I also don't see any gauges listed. No fuel pressure or oil pressure, or even fuel quantity. The only warning systems listed are stall and gear. I'm not sure what to make of this.

 

Larry

mooney_FAA_type_certificate.pdf

[201er]

Thanks everyone. From the replies you can see why I asked the question. If LASAR agrees, I will dump my combination EGT/OT gauge (which I never look at since I use the JPI for that information) and put the Ammeter in that hole. That will leave a 2 1/4 inch hole next to ASI, where I will (probably) mount an AOA indicator if I can be convinced by Alpha (at Oshkosh) that it can be calibrated for my Mooney.

Can you make them calibrate it for you?

[201er]

I thought all required equipment was listed in the type certificate? I just checked, I see no mention of egt/oat/clock/ammeter in the type certificate.

Larry, clock is required for IFR.

[larryb]

Larry, clock is required for IFR.

True. I just mentioned it is not in the type certificate. 91.205 has the rest of the required equipment. So my thinking is that it is the combination of the type certificate + 91.205 = required equipment for your plane. Much of what is listed in 91.205 is not included in the type certificate. I suppose that if the POH has a list it must be adhered to as well. I can't check my POH right now since it's in the plane. But if the POH doesn't have a list, then you are left with the type certificate + 91.205.

 

Regarding the clock, would the clock display in my GTN650 meet the requirement? My reading indicates it would.

 

(6) A clock displaying hours, minutes, and seconds with a sweep-second pointer or digital presentation.

[PTK]

Bennett -- the EGT is definitely not primary or required. I removed mine when I recently upgraded the engine analyzer to the 830.

Let me add to the confusion. During my recent panel upgrade, I was told that I could not remove the EGT/OAT despite having an 830 because the EGT/OAT was factory installed and the 830 is not primary.

I also had a similar experience! There seems to be confusion and can't get a straight answer. I had this EGT/OAT gauge on the right side also and NEVER did I look at it since I have the EDM in front of my face. I replaced it with a Davtron M655 primarily for readily available DA. It has a few other functions incl. OAT.

Because I couldn't get a straight answer if the combo gauge was necessary or not I had the installer just stow it behind the panel just in case!

I also took out the oem clock and updated it with an M802. I really like it because it has two displays. It permanently displays zulu time on the top display, as well as local time along with the usual timer functions on the other.

[jetdriven]

That's not my opinion.  It's what I was told by a very reliable source when I wanted to remove the OAT/EGT.  If the info I was given is incorrect, I would certainly appreciate an update.

Call my mechanic, they can remove it with a log entry if he agrees with you.  You have more glass than a 747-400, I find it laughable that your mechanic doesnt want to remove the OAT.

 

We dumped the OAT gauge for a Davtron M803. In addition to OAT, it also has bus voltage and a nice clock/flight timer.

[Marauder]

I have 4 sources of OAT! The Mooney one in the side window, the Aspens each have their own and now the JPI has added another one! Too many of them -- at least they agree...

[Oscar Avalle]

I have 4 sources of OAT! The Mooney one in the side window, the Aspens each have their own and now the JPI has added another one! Too many of them -- at least they agree...

 

Mine don't agree...but Bennet asked if we needed the Ammeter... I checked the POH and I could not find a reference to it... 

[jlunseth]

You can't stop at the POH with a Mooney.  You need to review the Type Certificate, http://www.67m20e.com/Mooney%20TCDS%202A3%20Rev%2052%20dtd%209DEC10.pdf

 

and since the aircraft was certified under CAR 3 and must have the equipment required in CAR 3, you need to check that also.  Here is a copy of CAR 3.  http://www.supercub.org/photopost/data/500/CAR-PART3.pdf .  In the type certificate, note the Required Equipment para. and all the numbered notes listed there, you have to check through those notes. 

 

Most 830's are not STC'd I don't believe, so if an ammeter or voltmeter is required equipment, having one on a non-STC'd 830 does not count for airworthiness.

[201er]

§ 3.675 Cylinder head temperature
indicating system for air-cooled engines. A
cylinder head temperature indicator shall be
provided for each engine on airplanes equipped
with cowl flaps. In the case of airplanes which do
not have cowl flaps, an indicator shall be
provided if compliance with the provisions of §
3.581 is demonstrated at a speed in excess of the
speed of best rate of climb.

 

Interestingly CHT and Fuel Pressure gauge are required equipment for our airplanes in order to be type certified. Ammeter, OAT, EGT are not. So it is my understanding they can be removed entirely. However, the CHT and Fuel Pressure, since they are not required for VFR/IFR flight can be marked inop (if broken) till the next annual. They way I understand it they are required for certification rather than flight rules or airworthiness.

[PTK]

This in an interesting question. Whether an ammeter is listed the Mooney put it in the panel. My question is would we want to be flying an aircraft that heavily depends on its electrical system without an ammeter? 

[Bennett]

Thanks for all the commentary and opinions relating to my question about removing the ammeter from my panel. Obviously there are many viewpoints, and I am still not convinced that I can have it removed to allow room for a AOA indicator, if I decide I want one. I also thought removing my factory combination OAT/EGT gauge and moving the ammeter to that hole could accomplish the same thing, but again I don't believe there is a clear answer if it can pass FAA scrutiny. If I were younger I think I would just build a RV10 and equip it the way I would want to using the newest avionics available to the experimental market.

[jetdriven]

This in an interesting question. Whether an ammeter is listed the Mooney put it in the panel. My question is would we want to be flying an aircraft that heavily depends on its electrical system without an ammeter? 

Ammeters are important for generator installations because you can often exceed the output of the generator at times, such as on final at night with everything turned on and low RPM.  With a generator you can see how many amps you have to shed.  I find a voltmeter more important for alternator airplanes. It shows system voltage. The early M20J's at least, have a voltage warning light. it flashes below 12 volts.