Adding basic IFR avionics to a C150

dmspilot

Final Approach
Joined
Oct 20, 2006
Messages
5,826
Display Name

Display name:
DISPLAY NAME
I have a Cessna 150 that's minimally equipped. The radio rack is original from 1975 except that the sole NAV/COMM has been replaced by an MX300. It also has an ADF, and, strangely, marker beacons but no glideslope. Also has a 4-pound paperweight aka LORAN. I would like to add enough equipment for basic IFR and to train instrument students.

At a minimum for IFR training, I would need to add a glideslope receiver and indicator. Preferably, I would also want to add a second NAV/COMM or just a NAV, and/or a DME, or a GPS that can at least be used in lieu of DME to identify fixes--I don't necessarily need GPS approach capability.

I have come up with a very interesting option which is to add a KNS-80 VOR/DME RNAV. Not because I actually want an RNAV, but because I would get a second VOR/LOC receiver, a glideslope, and a DME transceiver all in one box. I can probably get the KNS-80 and an indicator to go with it for ~$1,000. I know it's a large box but my panel appears to have the space--unless there's not enough depth. Am I crazy?

On the other hand, I am less concerned about spending money than I am about negative ROI (I wouldn't mind spending $ if it increases the value of the airplane).
 
I would stay away from the kns80,not worth the hassle or weight.
 
I would stay away from the kns80,not worth the hassle or weight.

Only two more pounds than the Loran it would replace. Add another pound for the indicator.
 
I would stay away from the kns80,not worth the hassle or weight.
The KNS 80 I had in my old Mooney was far more trouble than it was worth. It was OK when it worked, but let's just say I left a key to the airplane with the avionics guy. Far, far better to up the ante a little and go with a 430 or something.
 
The KNS 80 I had in my old Mooney was far more trouble than it was worth. It was OK when it worked, but let's just say I left a key to the airplane with the avionics guy. Far, far better to up the ante a little and go with a 430 or something.

Interesting, what kind of problems did it have? Just didn't work at all sometimes?

I realized it requires forced air cooling so installation might be more hassle than I thought. Will go back to the drawing board probably.
 
Interesting, what kind of problems did it have? Just didn't work at all sometimes?

I realized it requires forced air cooling so installation might be more hassle than I thought. Will go back to the drawing board probably.
I recall a fairly large number of display problems, but there were others. The hand-soldered circuit boards in those things just did not hold up to the vibration.
 
Apollo used to make slide-in replacement GPS for many LORANs.
 
What's about the garmin 300XL
 
If it were me, I would go for the maximum functionality for the least space and weight, probably a Garmin 430W or 650 at minimum. I would ditch the ADF for weight considerations, and of course the LORAN because it doesn't serve any purpose anymore.
 
Last edited:
If it were me, I would go for the maximum functionality for the least space and weight, probably a Garmin 430W or 650 at minimum. I would ditch the ADF for weight considerations, and of course the LORAN because it doesn't serve any purpose anymore.

Here we go again - someone spending 20k on "basic IFR equipment".

What he needs is a G/S receiver, $25 plus labor - it works with MX300, second COMM/GPS(and an audio panel), likely a GX50/60 that might be a slide-in replacement for the LORAN. Maybe around $1500 all in.
 
Here we go again - someone spending 20k on "basic IFR equipment".

What he needs is a G/S receiver, $25 plus labor - it works with MX300, second COMM/GPS(and an audio panel), likely a GX50/60 that might be a slide-in replacement for the LORAN. Maybe around $1500 all in.

Not exactly, he would also need a indicator with glideslope needle. all the slide in replacement gps's really weren't slide in, they required a new antenna and sometimes a new coax. I Don't believe the gx was a slide in for any of the loran units. I believe that all the slide ins were all vfr units.

Bob
 
Not exactly, he would also need a indicator with glideslope needle. all the slide in replacement gps's really weren't slide in, they required a new antenna and sometimes a new coax. I Don't believe the gx was a slide in for any of the loran units. I believe that all the slide ins were all vfr units.

Bob

GX50/55/60/65 are slide-ins for some LORANs too and can be installed VFR or IFR. Not much to it, the installation manual explains the requirements and there are good template AFMS available online as well.
 
GX50/55/60/65 are slide-ins for some LORANs too and can be installed VFR or IFR. Not much to it, the installation manual explains the requirements and there are good template AFMS available online as well.

Good to know. It's been so long since they hit the market I could not recall which ones were slide in.
 
Good to know. It's been so long since they hit the market I could not recall which ones were slide in.

Actually, scratch the 50 and 60, they have comm too so aren't slide ins, the GPS only units are slide in.
 
I have a Cessna 150 that's minimally equipped. The radio rack is original from 1975 except that the sole NAV/COMM has been replaced by an MX300. It also has an ADF, and, strangely, marker beacons but no glideslope. Also has a 4-pound paperweight aka LORAN. I would like to add enough equipment for basic IFR and to train instrument students.

At a minimum for IFR training, I would need to add a glideslope receiver and indicator. Preferably, I would also want to add a second NAV/COMM or just a NAV, and/or a DME, or a GPS that can at least be used in lieu of DME to identify fixes--I don't necessarily need GPS approach capability.

I have come up with a very interesting option which is to add a KNS-80 VOR/DME RNAV. Not because I actually want an RNAV, but because I would get a second VOR/LOC receiver, a glideslope, and a DME transceiver all in one box. I can probably get the KNS-80 and an indicator to go with it for ~$1,000. I know it's a large box but my panel appears to have the space--unless there's not enough depth. Am I crazy?

On the other hand, I am less concerned about spending money than I am about negative ROI (I wouldn't mind spending $ if it increases the value of the airplane).
For an IFR C150, you might consider an audio panel that will also be your intercom and your Com 2.
At a MAP of $2595, best value in the certified world.
Www.ps-engineering.com/PAR200.shtml
Mark Scheuer
PS Engineering
(Consider the GNS430W for Com 1)
 
For an IFR C150, you might consider an audio panel that will also be your intercom and your Com 2.
At a MAP of $2595, best value in the certified world.
Www.ps-engineering.com/PAR200.shtml
Mark Scheuer
PS Engineering
(Consider the GNS430W for Com 1)

That's a great option, especially if you wanted to pair it with the ValAvionics INS429 (nav only, no comm) and then later install something like a 430w
 
Good to know. It's been so long since they hit the market I could not recall which ones were slide in.

Actually, scratch the 50 and 60, they have comm too so aren't slide ins, the GPS only units are slide in.

The Loran is a Narco unfortunately so I believe none of them would be slide ins in my case. According to Bennett the Apollo GX-60 and 65 are the ones with the Comm, the 50 and 55 are without the comm, the ones that end in 0 are IFR approach and the ones that end in 5 are IFR enroute only.

Any comments on the SL-50 GPS? It's enroute only but it's inexpensive. I'm also looking at the the KLN-89B, 90B, 94, and 90A (90A is enroute only). Do you need the whole shebang--CDI and Annnunciator panel, for IFR enroute only approval?

My understanding is that both the Apollo/Garmin GX series as well as the KLN series all have display issues that are not economically repairable. Not sure about SL-50. Is one of these more reliable or less costly to repair than the others? What about database costs?

I think I might just start by trying to add the glideslope to the existing NAV/COMM as a first step and then decide on the rest at a later date.
 
Last edited:
The Loran is a Narco unfortunately so I believe none of them would be slide ins in my case. According to Bennett the Apollo GX-60 and 65 are the ones with the Comm, the 50 and 55 are without the comm, the ones that end in 5 are IFR approach and the ones that end in 0 are IFR enroute only.

Any comments on the SL-50 GPS? It's enroute only but it's inexpensive. I'm also looking at the the KLN-89B, 90B, 94, and 90A (90A is enroute only). Do you need the whole shebang--CDI and Annnunciator panel, for IFR enroute only approval?

My understanding is that both the Apollo/Garmin GX series as well as the KLN series all have display issues that are not economically repairable. Not sure about SL-50. Is one of these more reliable or less costly to repair than the others? What about database costs?

I think I might just start by trying to add the glideslope to the existing NAV/COMM as a first step and then decide on the rest at a later date.

I got my numbers mixed up too. The non-comm Apollos are the slide ins. 55 is en-route only, 50 is en-route and approach.

The installation manual for whichever one you decide to go for will specify the requirements for IFR installation. GX55, which is en-route only, requires a CDI and a lamp annunciator. Mid-continent makes (well, made) an annunciator/CDI that has both in same package. These can be found second hand for $50-150.
The display issues aren't a big deal really. They usually fail pretty gradually as dead pixels take over, but replacements(not screens, but serviceable units) are easy to find, if you get 3-4 years out of one, then have to replace, it's not a huge cost.

Jeppesen sells you a database, they weren't outrageously expensive.
 
any of the multi-line apollo gps units are doa when the screen dies. they are just not available. since the sl-50 was a single line character screen i would think that a replacement is available. most of the single line character displays used were off the shelf standard displays. now, getting someone to replace it could be difficult, a lot of shops will not work on older radios.
 
OP,
I am going through a similar panel process right now. (see thread 172 panel)
I considered old/obsolete avionics too. The labor will be nearly the same no matter what vintage you install. I'd consider how long you plan on keeping the plane. If it's long term, I'd suggest going with current avionics.
Another option is to look for "slide in" replacements that are new, such as the MX-170c.

I may have missed it, but what is your ADSB plan?
 
If your plan is to train students for the instrument rating, I would say you should really look at getting a 430W or better. That is, unless you have stash of instrument students who won't have access to GPS-approach equipped planes for rent after they have their rating. If I was investing in an instrument rating as a student today, there is no way I would spend money renting something that wasn't capable of training me to operate using modern airspace. I would not want to train in something with an ADF, because I would have to waste time and money learning to use it just for the practical test. When I was an IR student, the club I was in had some planes that had ADF, and others that did not. While I did spend some time in the simulator doing ADF approach work, I made sure that the plane I used for the check ride did not have an ADF, as it was nearly obsolete (at least in my area) 14 years ago when I got the IR.

Just my $0.05.
 
If your plan is to train students for the instrument rating, I would say you should really look at getting a 430W or better. That is, unless you have stash of instrument students who won't have access to GPS-approach equipped planes for rent after they have their rating. If I was investing in an instrument rating as a student today, there is no way I would spend money renting something that wasn't capable of training me to operate using modern airspace. I would not want to train in something with an ADF, because I would have to waste time and money learning to use it just for the practical test. When I was an IR student, the club I was in had some planes that had ADF, and others that did not. While I did spend some time in the simulator doing ADF approach work, I made sure that the plane I used for the check ride did not have an ADF, as it was nearly obsolete (at least in my area) 14 years ago when I got the IR.

Don't worry. You're not in the target market. :rolleyes:
 
I kindof agree with Jeff here. An IFR trainer without a reasonably modern GPS has limited training value. I've been told that my airplane has a "perfect panel for IFR training", and as I've gone through my own IFR I can now see why. It has:

GNS-430W with 106 CDI/GS
KX-155 with CDI
STEC-20
KMA-24
 
Apparently the meaning of the word "basic" is lost on some.

The number of people that want to get instrument ratings in any 150 is already limited regardless of how many gadgets it has.
 
No mention of budget?
I have a gx50, great unit, takes a little getting used to, but when you do it's very capable. Get a later unit and the screen problems were pretty much solved.
I recently saw a GX50, SL30, sl15 panel, indicator and xponder with encoder and annunciator/suicide switch stack advertised for $5k on the airplane stuff for sale group on Facebook. Lots of capability, little money.
 
Last edited:
Do you have any instrument students that would train in such a panel? Or is this an purely an academic question?
 
No mention of budget?
I have a gx50, great unit, takes a little getting used to, but when you do it's very capable. Get a later unit and the screen problems were pretty much solved.
I recently saw a GX50, SL30, sl15 panel, indicator and xponder with encoder and annunciator/suicide switch stack advertised for $5k on the airplane stuff for sale group on Facebook. Lots of capability, little money.

Thank you for the information. How do I know if a particular unit is a later with solved screen problems?
 
Thank you for the information. How do I know if a particular unit is a later with solved screen problems?

Wel, now that's a good question. As it was explained to me, the displys were manufactured in two production runs, the first had epoxy sealant problems at the edges that were corrected before the second. At what serial number break that occurred, I don't know. I believe the GX series was discontinued in 2008 or so.
 
Back
Top