Avionics Research & Installation

Scott F. Smith


Buying a Used Single Engine Aircraft
Engine Research & Installation
Avionics Research & Installation
Air Frame Repair
Finding a Flight School
Negotiating a Lease Back Agreement
Commercial Operations
Cash Flow Analysis

Even though I flew 50037 for approximately 20 hours before having the engine overhauled, it took some time to decide what the plane needed in terms of Avionics. We decided that we need at least be able to tune VORs and intercept a the localizer for IFR approaches.

N50037 didn't come with much in terms of avionics. The radio was a single Val Com Radio with an LED that had missing portions of the numbers. It also had a NARCO AT50A Transponder with an Ameri-King Encoder.

The turn coordinator didn't work, but the Directional Gyro, Attitude Indicator, Vertical Speed Indicator, Altimeter, Airspeed Indicator, Fuel Gauges, Oil Pressure, Engine Temp, Volt Meter, and Tachometer all worked.

Below is a picture of the panel I took on the trip from Florida to Ohio.

Below is a picture of the panel after upgrade.

Upgrades Included:

Bendix/King KX-155 Nav/COM.
Bendix/King KMA-26 Audio Panel
Dual Head Set Jacks
New Turn Coordinator
Factory Overhauled KI-209A Glide-Slope/Localizer Indicator
Push-to-Talk Grips
Pull-Start Handle to Key Starter Conversion
5 Amp Circuit Breaker for the Starter.
New Pitot Heat Switch
New Flashing Beacon Switch
Several Fuse Housings Replaced
IFRCertified with a KLN-89B GPS
New Narco KX-155 Solid State Transponder (Not Pictured Yet)

For added safety, I also carry GPSMap 196 VFR Only but with a current Jeppesen Database America's database and an ICOM A-23 Portable NAV/COM for Communications back-up. (removable)

I decided on using an avionics shop called Mac-Michael Avionics to put in the new KMA-26 Audio Panel, KX-155 Nav/Com, and KI-209A Glide Slope Indicator, and Glide Slope Antenna. Another company called Spirit Avionics did the IFR Certification. What still amazes me is how much avionics cost to purchase and install. Typically you are not able to buy avionics over the counter, but finding used avionics with a 6 month warranty can save a bundle of money. Used avionics from an authorized shop and with the proper paperwork supplies 100% of the functionality as new. So I think this is the way to go with respect to avionics, at least for a 1968 C-150.

One thing I cannot emphasize enough is keeping all the paperwork and log books for the plane up to date. FAR Section 91.403 charges the owner/operator responsible for the airworthiness of the aircraft. Making sure your aircraft meets all Airworthiness Directives is also the responsibility of the owner/operator. I like the fact there are a lot of checks and balance in the aviation industry.

I also think it is important to do thorough research before making a decision as to what equipment to put in a plane. One major factor affecting the Cessna 150 is weight and balance. Below is a weight and balance worksheet for N50037. If you are not careful you can  put your plane over its useful load very quickly. Below is the estimated weight and balance after the IFR Certified GPS.

Cessna 50037 Weight & Balance Qty. Units Multiplier Units Weight Arm Moment
        (lbs.) (inches) (lb-inches)
Empty Weight (Includes Unusable Fuel)         1,072.45 33.55 35,980.70
Oil (6 qts. Full oil may be assumed for all flights) 6 Qts 1.875 lbs 11.25 -9.09 -102.27
Useable Fuel (Standard - 22.5 gal @ 6 lbs./gallon) 22.5 Gal 6 gal/hr 135.00 42.22 5,700.00
Pilot         180.00 39.00 7,020.00
Passenger         180.00 39.00 7,020.00
Baggage - Area 1 (or children on child's seat)         5.00 64.00 320.00
Baggage - Area 2         5.00 84.00 420.00
KLN-89B GPS         4.40 12.40 54.56
GPS Antenna         0.30 43.50 13.05
GPS Cable Assembly         0.80 18.50 14.80
KX-155 w/no GS         3.50 12.50 43.75
KI-208 Nav Indicator         1.00 13.90 13.90
VHF COM Antenna         0.50 56.69 28.35
COM Antenna Cable         0.40 25.00 10.00
Antenna Coupler         0.20 18.50 3.70
Annunciator Panel         0.50 16.00 8.00
Ramp Weight         1,600.30 509.67 56,548.53
Fuel Allowance for engine start, taxi, and runup 6 lbs 0.2 hours 1.20 49.69 59.63
        1,599.10 459.98 56,488.90
Moment /1000 56.49 Within Limits   60 Max Allowable
  CG 35.33        
Fuel Avail   Reserve   Endurance Endurance  
(Hours)       Hours Minutes  
    Day   Day Day  
3.75   0.50   3.25 195  
    Night   Night Night  
3.75   0.75   3.00 180  



• Home • Introduction • Buying and Aircraft • Engine Research & Inst. • Avionics Research & Inst. • Air Frame Repair • Finding a Flight School • Negotiating a Lease Back Agreement • Insurance • Maintenance • Commercial Operations • Cash Flow Analysis • Conclusion •

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