Updating an Older Airplane
A forty year old Cessna 172gets a facelift and a new heart
April, 2005
Stan Cooper
A Metamorphosisfrom This… …to This
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N2686U – A ’63 Cessna 172D
• 2200 Hours Airframe Total Time• 220 Hours SMOH – Continental O-300-C• Original “Shotgun” Panel• Avionics Stack Limited to ½ Height (“T” Control
Column)• Optional 35 Amp DC Generator Electrical
System• Circuit Protection: AGS Fuses• Dual Narco Mark 16 360 Channel NavComs• 30 Years at SNA (Orange County) – Lots of
Surface Corrosion• Two previous owners (17 years) were A&P
mechanics and CFIs who taught their wives and children to fly in the airplane
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Why A 1963 Model?
• ’63 was the first year the 172 had the “Omni-Vision” rear window – looks similar to the new 2003 172S
• Higher gross weight (2,300 lbs vs. 2,250 lbs) with same empty weight, resulting in higher useful load than earlier years
• The ’63 still had manual flaps – simpler, faster to deploy and retract, and arguably more reliable than electric flaps
• Continental O-300 six cylinder engine (some will debate whether this is an asset or a liability)
• At $26,500 I could afford it ☺
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The Project Scope• Replace the instrument panel with a new STC’d one from Avion
Research conforming to FAR 23.1321, including new AI and DG• Update the electrical system from DC generator to 50 amp STC’d
Skytronics alternator; replace fuses with circuit breakers• New avionics stack-
– PS Engineering 6000 Audio Panel/Intercom– King KLX 135A GPS/Com– King KY97A Comm– Narco NAV 121 VOR Receiver– Monroy ATD300 Traffic Detector– Garmin GTX 320A Solid State Transponder– S-TEC 30 Autopilot– King KMD 150 MFD/GPS
• New electronic tach, volt/ammeter, and chronometer• Strip old paint, remove corrosion, prime and paint• New interior, including B.A.S. shoulder harnesses• Six new ECi “TITAN” cylinders with Real Gaskets pushrod tubes
A Few Words to the Wise
• Before beginning major work on any certificated airplane, discuss the project with your A&P/IA and your local FSDO inspector.
• Tell them exactly what you want to do and how you plan to do it.
• Find out what paperwork will be required and agree on who’s going to do what.
• After you’ve described what you’re going to do, don’t make any changes.
• Keep the FSDO inspector informed of your progress and invite him/her to stop by any time to inspect the work.
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The Mid-eighties Paint Job
….. It probably looked great at the time.
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The 1963 Vintage “Shotgun” Panel
’63 was the last year the 172 used a “T” control column.
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The “U” Column Permits a Full HeightCenter Avionics Stack
… and the ’64“U” Control
Column
The ‘63 “T” Control Column
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Hmmm.. Do I Really Want To Do This?? Original “T” Control Column
(Limits avionics stack tohalf height)
Original Defroster Nozzle(Interferes with new gyro
instrument vacuum fittingsand hoses)
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Getting There..New Defroster Nozzle(Prevents interference
with AI and DG vacuumfittings and hoses)
New “U” Control Column(Permits full height
Avionics stack)
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Testing the avionics andPre-wiring the panel…
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• Avionics and harness bench tested before installation• All panel instrument and avionics grounds terminate
on a copper buss connected directly to negativebattery pole (fuselage not used for ground return – toomuch noise)…
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The New Electrical Wiring Diagram
VA-1A-50
AVIONICSMASTER
MASTER
ALT
BAT
FIREWALL
ALTERNATOR
A
C
D
B
JASCOJ12M20SP
12VCONTROLLER
REDORG
GRN
BLK
YEL
PRI
MARY
BUS
AVI
ONICS
BUS
8 AWG SHIELDED 50
ALT
AMMETER
OUTPUT(WHITE)
REG(AUX)(RED)
ALT FIELD(GRN)
GROUND(BLK)
18 AWG
20 AWG
REG
7
5
ALTFIELD
18 AWG
STARTER"T" HANDLE
10
CABINLIGHTS
18 AWG EB1 R
L
FUEL GAUGES
EB5
EB4
EB2
FUEL GAUGE TRANSMITTERS
CESSNA DWG 0500062 PAGE 8.1REV D 9-11-62
CABINLIGHTS
18 AWG LA7MAP LIGHT
18 AWG LA1
DOME LIGHTCESSNA DWG 0500062 PAGE 11.1 REV D 9-11-
62
INSTRLIGHTS
10 18 AWG LB1INSTR
LIGHTS
18 AWG LB2INSTRLIGHTINSTR & COMPASS
LIGHTS
RADIO LIGHTS
18 AWG LB3 18 AWG LB4
COMPASSLIGHT
22 AWG P1A, KLX135A22 AWG P97A1, PIN B, KY97A22 AWG P101, PIN 4, AT50A22 AWG P810, PIN 27, NAV121
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NAVLIGHTS
NAVLIGHTS
18 AWG LD2
18 AWG LD4
18 AWG LD11
PORT
STARBOARD
TAIL
CESSNA DWG 0500062PAGE 11.2 REV D 9-11-62
CESSNA DWG 0500062PAGE 11.4 REV D 9-10-62
STROBEBCN
16 AWG LF2
FLASHING BEACONCESSNA DWG 0500062
PAGE 11.5 REV D 9-11-62
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LANDINGTAXI
LANDINGTAXI LANDING
TAXI
OFF
14 AWG LC2
14 AWG LE1
LANDING (INBOARD)
TAXI (OUTBOARD)CESSNA DWG 0500062
PAGE 11.3 REV D 9-10-62
2TURN COORD
18 AWG FA1 + -TURN & BANK
18 AWG FA2 CESSNA DWG 0500062PAGE 9.1 REV D 9-10-62
18 AWG FC23STALL WARN
WARNINGHORN
18 AWG FC3
STALL SWITCHLEFT WING LEADING EDGE
CESSNA DWG 0500062PAGE 15.1 REV D 9-10-62
AUX POWER10 18 AWG CIGAR LIGHTER RECEPTACLE CESSNA DWG 0500062
PAGE 13.1 REV D 9-11-62
RADIO 1
RADIO 2
RADIO 3
RADIO 4
3
10
7
5
18 AWG
20 AWG
20 AWG
PIN 20, J1, PMA 6000 AUDIO PANEL - PS ENGINEERING DOCUMENT 200-066-0002 REV. 2, MAY 1999
PIN 7, P810, NAV121 VOR RCVR - NARCO NAV121 MAINTENANCE MANUAL 03723-0600, 9/79, TABLE 2.2A & FIG. 2-9
PIN 26, P810, NAV121 VOR RCVR - NARCO NAV121 MAINTENANCE MANUAL 03723-0600, 9/79, TABLE 2.2A & FIG. 2-9
18 AWG
18 AWG
18 AWG
PIN 6, P4001, KLX135A GPS/COMM - ALLIED SIGNAL INSTALLATION MANUAL 006-10500-0003, REV. 3, AUG 1995, FIG. 2-1, SHEET 3 OF 5
PIN 7, P4001, KLX135A GPS/COMM - ALLIED SIGNAL INSTALLATION MANUAL 006-10500-0003, REV. 3, AUG 1995, FIG. 2-1, SHEET 3 OF 5
PIN 8, P4001, KLX135A GPS/COMM - ALLIED SIGNAL INSTALLATION MANUAL 006-10500-0003, REV. 3, AUG 1995, FIG. 2-1, SHEET 3 OF 5
18 AWG
18 AWG
PIN R, P97A1, KY97A COMM - ALLIED SIGNAL INSTALLLATION MANUAL 006-00674-0003, REV. 3, APR 1994, FIG. 2-8
PIN 14, P97A1, KY97A COMM - ALLIED SIGNAL INSTALLATION MANUAL 006-00674-0003, REV. 3, APR 1994, FIG. 2-8
18 AWG PIN 16, P101, AT50A TRANSPONDER - NARCO AT50A MAINTENANCE MANUAL 03604-602, SEPT 1972, FIG. 2-1
CENTER PIN, POWER JACK, ATD-300 - MONROY ATD-300 OWNERS MANUAL MA-300, REV 1.6, 1-2004, F IG. 622 AWG
6 AWG
18 AWG
4 AWG
STARTER
+
-
D.C. POWER WIRING - CESSNA 172D N2686US/N 17250286 S. COOPER REV. 7/13/2004
AMMETERSHUNT
18 AWG
18 AWG
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STROBEBCN
OFFSTROBE (NC)
BCNFLASHER
ASS'Y
LAMP
DIMMERMODULE
LM 150K
V IN
1 F 2 - 11 VDCOUTPUT
ADJUSTMENT
CASE IS OUTPUT
13.8 VDC
240
.1 F
5 K
INSTRUMENT LIGHTS DIMMERMODULE
BATTERY CONTACTOR
DIMMERMODULE
S50ORG
BRN
BLK WH/RED
1 AFUSE
RED
WH/BRNCLOCKLIGHT
1
TACHWHITE
BLK
TACHOMETER
P-1000
IGNITION SWITCHL R
L.H. MAGR.H. MAG
CESSNA DWG 0500062PAGE 5.1 REV D 9-11-62
FAA Form 337, Block 8 U
.S.A. N2686U
Date July 13, 2004
AVIONICSFAN
2A FUSE
TROLLFN-200
18 AWG PIN 37, 37 PIN CONN, KMD 150 MFD/GPS - ALLIED SIGNAL INSTALLATION MANUAL 006-10607-0000, REV. 0, NOV 1999, FIG. 2-10
5S-TEC 30 AUTOPILOT
18 AWGAP/TURN COORD PIN 14AP/PITCH COMP PIN 1
Fitting the New Panel and Avionics
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Avionics Interconnection DiagramPMA6000TOP (J2)
BOTTOM (J1)
3C1A5E6F910K
4DN12
9
PR19L
10
HV16MT
12
20
322W
8Y
1Z
ATD-300
KY97AJ97A1
P1
CO-PILOT PHONES HICO-PILOT PHONES LOPASS PHONES HIPASS PHONES LO
PASS 1 PHONES
PASS 2 PHONESPASS 1 MIC HIPASS 1 MIC LOPASS 2 MIC HIPASS 2 MIC LO
CO-PILOT MIC AUDIOCO-PILOT MIC PTTCO-PILOT MIC LO
CO-PILOT MICCO-PILOT PTT INCONTROL WHEEL
EXTERNAL ENTERTAINMENT
KLX135A AUDIO HIKLX135A AUDIO LOKLX135A MIC AUDIO HIKLX135A MIC KEY
KLX135A SPKR LOAD
KY97A AUDIO HIKY97A AUDIO LO
H7J9E5R14F6S
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KY97A MIC AUDIO HIKY97A MIC KEY
KY97A SPKR LOAD
TRAFFIC ANNUNCIATOR
600 OHM AUDIO(RING OF "PHONE-SPEAKER" JACK)
12 VDC POWER"RADIO 3" CKT BRKR
NAV121 AUDIO HI
PILOT PHONES HIPILOT PHONES LOSPKR HISPKR LO CABIN SPEAKERPILOT MIC AUDIOPILOT MIC PTTPILOT MIC LO PILOT PTT IN
CONTROL WHEEL
AIRFRAME GROUND
AVIONICS INTERCONNECT WIRING - CESSNA 172D N2686US/N 17250286 S. COOPER REV. 5/28/2004
NAV121J810
3672619
MOUNTINGSTUD
12 VDC POWER - "RADIO 1" CKT BRKR
12 VDC POWER - "RADIO 1" CKT BRKR
12 VDC POWER - "RADIO 4" CKT BRKR
FAA Form 337, Block 8, Item
3 U.S.A. N
2686U Date July 13, 2004
KLX135AP4001
13143PN
678FJ
12 VDC POWER - "RADIO 2" CKT BRKR
DATABASE OUT
2JK15
DATABASE IN
GROUND
TO RS232 JACKON PANEL
(GPS DATA LOADER)
KMD150P1
3725131230
12 VDC POWER - “RADIO 4” CKT BRKRGROUND
+ RT+ LT
S-TEC 30
653
35109
19422021
GPS GAINJMPR
CUT FORDG
DG52D54
EBDA
SIG REFEXC REFAC HDG
S-TEC 30 Autopilot Installation
Panel Showing Turn Coordinator/Roll Computer and DG with Heading Bug
Pitch Computer Pitch Servo Pressure Transducer Roll Servo16
Solid State Dimmers Replace Rheostat
- Instruments- Radios
Same circuitas in new 172R,except set upfor 12 V systeminstead of 24 Vsystem –
Safer and moreefficient thanrheostats
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Item Maximum Current Load
1. PMA 6000 Audio Panel 1.00 Ampere2. KLX 135A GPS/Comm 6.30 Amperes (Tx)*3. KY97A Communications Transceiver 1.10 Amperes (Rx)4. GTX 320A Transponder 2.00 Amperes5. ACK A30 Encoder 0.30 Ampere6. NAV 121 VOR Receiver 0.87 Ampere7. KMD 150 MFD/GPS 1.50 Amperes8. S-TEC 30 Autopilot 5.00 Amperes9. ATD-300 Traffic Detector 0.20 Ampere10. P-1000 Tachometer 0.20 Ampere11. VA-1A-50 Volt/Ammeter 0.10 Ampere12. Dome Light (GE 1816 Bulb) 0.33 Ampere13. Map Light (GE 58 Bulb) 0.58 Ampere14. Fuel Quantity Indicators 0.36 Ampere15. Instrument Lights (GE 94 Bulb) 1.10 Amperes16. Compass Light 0.08 Ampere17. Landing Lights (Taxi and Landing) 15.60 Amperes18. Strobe 1.70 Amperes19. Navigation Lights 5.60 Amperes20. Stall Warning Horn 0.25 Ampere21. S-TEC Turn Coordinator 0.30 Ampere
===============TOTAL MAXIMUM LOAD 44.47 Amperes
* KLX 135A draws 6.3 amperes in Transmit, KY97A draws 6.0 amperes transmit. Sinceonly one comm unit transmits at a time, the table shows worst case. Transmit loadis transitory, not continuous.
Electrical System Load Budget
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Weight & Balance
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Weight & Balance (Cont’d)
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Finally!!!
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Millennium Falcon??
Exterior stripped, surface corrosion removed,Alodined, and prepped for primer
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Primed and ready for paint..
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Photo from ’63 Factory Brochure
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…And the New Paint on N2686U
The strip and paint was done by T&P Aero Refinishersin Salinas, CA. I think they did a fantastic job..
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Interior – Before…
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Interior – and After…
Kit by Hangar Bay Aircraft Interiors
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New ECi Cylinders
1. Original Continental Cylinders
2. Baffling, exhaust system,intake system, old cylinders
removed
4. New ECi cylinders with Real GasketsSTC’d pushrod tubes installed
5. All back together with powdercoatedbaffling, new Lord engine mounts
3. Cam and lifters ingood shape
Costs (Labor Not Included)• N2686U . . . . . . . . . . . . . . . $26,500• Avion Panel and Control Wheels . . . . . . . 3,395• New RC Allen AI . . . . . . . . . . . . . 425• New Sigma Tek 4000C DG with Heading Bug . . . . 1,191• King KLX-135A GPS/Comm . . . . . . . . . 2,095• King KY-97A Comm . . . . . . . . . . . . 989• Garmin GTX 320A Transponder . . . . . . . . 1,230• PS Eng PMA6000 Audio Panel/Intercom . . . . . . 904• Narco NAV121 VOR Rcvr . . . . . . . . . . 1,149• King KMD 150 MFD/GPS . . . . . . . . . . 2,875• S-TEC 30 Autopilot . . . . . . . . . . . 7,845 • Skytronics/Jasco Alternator . . . . . . . . . 724• Monroy ATD-300 Traffic Detector . . . . . . . 595• Horizon Tach, EI Volt/Ammeter, Clock . . . . . . 861• Miscellaneous (wire, breakers, hoses). . . . . . 500• Strip and Paint (includes labor) . . . . . . 13,000• New Interior and B.A.S. Harnesses . . . . . . 2,500• Six ECi TITAN cylinders and STC’d pushrod tubes . 5,000
=======TOTAL $71,778
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LET’S GO FLYING!
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