Cessna 175 Skylark

The Cessna 175 Skylark is a four-seat, single-engine high-wing aircraft produced from 1958 to 1962, with 2,106 built. It occupies a unique and somewhat tragic niche in general aviation history — an airplane that was faster and more powerful than the Cessna 172 it was based on, but doomed by its Continental GO-300 geared engine's reputation for unreliability. Cessna dropped the model after just five years of production, though the 175 airframe itself lived on as the basis for later 172 variants and the T-41 Mescalero military trainer.

The 175 is two fundamentally different airplanes depending on its engine. With the stock GO-300, it is a maintenance-intensive headache available at rock-bottom prices. With the Lycoming O-360 STC conversion, it becomes a genuine hidden gem — a 180 HP Cessna high-wing with better performance than a standard 172, for less money than a comparable Skyhawk. Understanding this duality is essential to evaluating any 175 on the market.

The "Skylark" name was applied to deluxe-trim 175s starting with the 1960 model year (175A). In common usage, "175" and "Skylark" are used interchangeably.

All variants share the same basic airframe, which is dimensionally very close to the contemporary Cessna 172. The 175C is the most refined version with its constant-speed prop, cowl flaps, and higher gross weight, but the engine reliability concerns apply equally across all variants.

With the stock GO-300, the 175 cruises at 117-122 KTAS — approximately 15 mph faster than the contemporary 145 HP Cessna 172. The performance gain comes from the 30 additional horsepower extracted through the geared engine's reduction drive, which allows the engine to run at 3,200 RPM while the propeller turns at a more efficient lower speed.

Real-world owners report cruise speeds closer to 115-120 KTAS with fuel burns of 9-11 GPH depending on power setting and altitude. The 175 Owner's Manual advertises 850 fpm climb at sea level, which is respectable for the era and gross weight.

The critical performance note for the GO-300 is operational: the engine must be operated at high RPM (above 2,500 RPM) at all times. Below 2,500 RPM, the GO-300 does not generate sufficient oil pressure for adequate lubrication and cooling of the reduction gearbox. This is the single most important operational fact about the 175, and ignorance of it has destroyed more GO-300 engines than any design defect. The original POH compounded the problem by listing cruise data down to 2,400 RPM, creating a misleading impression that sustained low-RPM cruise was advisable.

Descents must be managed carefully — the reduction drive allows propeller windmilling to drive the engine, which can cause damage. Pilots must maintain a load on the engine during descent, avoiding idle-power letdowns.

With the O-360 conversion, the airplane transforms: 180 HP with a direct-drive engine, 1,800-hour TBO, standard operating procedures, and cruise speeds of 120-125 KTAS. The converted 175 is essentially a 180 HP Cessna high-wing that predates the 172N/P by two decades.

The 175's useful load of approximately 1,011 lbs (varies by variant and equipment) is competitive with the 172 of the same era. Full fuel plus two adults leaves adequate margin for baggage. Four-up trips require reducing fuel, but a 35-gallon fuel load still provides over 400 nm range — entirely adequate for most missions.

The 175C variant with its 2,450-lb gross weight has the best payload-range combination in the family, offering an extra 100 lbs of useful load over earlier models.

Mission scores below are for the stock GO-300 configuration. An O-360-converted 175 would score similarly to a Cessna 172N/P with 180 HP.

• Flight Training (4): The GO-300's operational restrictions and maintenance demands make it a poor training platform. The engine requires specialized knowledge that student pilots should not need to manage. An O-360 conversion raises this to a 6-7.
• Backcountry (3): Fixed gear and high wing are good, but the GO-300's sensitivity to power management during descents is a liability in mountainous terrain. Airframe performance is adequate.
• Business Travel (3): Marginal speed and range. The GO-300's short TBO and maintenance needs make it unreliable for schedule-dependent travel. An O-360 conversion improves this to a 5.
• Aerobatics (1): Not certified for aerobatic flight.
• Cross-Country (5): Adequate speed and range for regional trips. The GO-300 demands constant attention to engine management. With the O-360, this becomes a solid 7.
• Cargo Hauling (3): Useful load of 1,011 lbs is decent, but the 172-sized cabin limits volume.
• Local Fun (5): A pleasant-flying Cessna high-wing for weekend flying, provided you respect the GO-300's quirks. With the O-360, it is a cheerful and inexpensive fun flyer (7).
• Surveying (5): High wing provides good ground visibility. Performance is adequate for the mission.

Most surviving 175s have been through multiple avionics upgrades over their 60+ year lives. The panel is standard Cessna 172-era dimensions, and all 172 avionics solutions fit.

• Budget ($25K-$40K aircraft): Expect original or vintage avionics — a single nav/com, possibly no GPS. These are VFR-only machines unless the buyer invests in avionics.
• Mid-range ($40K-$70K): Basic IFR GPS (Garmin GNS 430 or GTN 650), ADS-B compliant, functional panel. These are typically O-360-converted aircraft.
• Premium ($70K-$110K): O-360 conversion plus modern avionics — Garmin G500/GTN 750, autopilot, full IFR capability. These aircraft represent the best value proposition in the 175 market.

Given the low hull values of stock GO-300 aircraft, investing heavily in avionics is not recommended unless the engine conversion is also planned. See avionics-pricing for current equipment costs.

The O-360 Conversion — The STC That Changes Everything

The most important modification available for the Cessna 175 is the Lycoming O-360 engine conversion. Multiple STCs exist, including the Bob Williams STC and others. This conversion replaces the problematic geared Continental GO-300 with a direct-drive Lycoming O-360-A1A or O-360-A1D producing 180 HP.

The conversion economics: The STC paperwork costs $1,250-$1,750. A used mid-time O-360 engine can be sourced for $6,000-$10,000. A new or overhauled propeller and governor cost $5,000-$8,000. Labor runs $5,000-$10,000 depending on the shop. Total all-in cost is typically $20,000-$35,000, and the conversion immediately adds that much or more to the airplane's value.

Strategic buy: Purchase a low-airframe-time GO-300 175 for $25,000-$35,000, invest $25,000-$30,000 in an O-360 conversion plus basic avionics, and own a 180 HP Cessna high-wing for $50,000-$65,000 — significantly less than a comparable 172 with the same engine.

Stock GO-300

• Parts availability: Poor and declining. Continental GO-300 parts are scarce, with limited core availability for overhaul. Some parts are available only through salvage yards or specialty suppliers.
• Mechanic familiarity: Specialist. Few A&Ps have hands-on experience with geared Continental engines. Finding a shop comfortable with GO-300 overhauls requires research.
• Annual inspection cost: $2,000-$3,500. The airframe inspection is standard Cessna, but GO-300 inspection items add time and expertise requirements.
• Engine overhaul: $28,000-$35,000 for a GO-300 overhaul, IF parts can be sourced. Increasingly, owners find that overhaul cost approaches or exceeds the airplane's value, making the O-360 conversion the economically rational choice.

O-360 Converted

• Parts availability: Excellent. The Lycoming O-360 is one of the most common GA engines ever built.
• Mechanic familiarity: Universal. Every A&P knows the O-360.
• Annual inspection cost: $1,800-$3,000. Standard Cessna single-engine annual.
• Engine overhaul: $22,000-$28,000 for a field overhaul. Factory reman available.

See maintenance-ecosystem for general maintenance context.

The 175 market splits into two completely separate valuations:

Stock GO-300 Aircraft

O-360 Converted Aircraft

The price premium for the O-360 conversion is significant and well-justified. A converted 175 with modern avionics competes directly with 172N/P Skyhawks that cost $20,000-$40,000 more. This is the core of the "hidden gem" thesis — the 175's bad reputation suppresses prices even for converted examples.

GO-300 Engine-Specific Issues

The Continental GO-300's reduction gearbox is the primary reliability concern. The gearbox transfers power from the engine crankshaft to the propeller through a set of reduction gears, and these gears are the Achilles heel of the design.

• Reduction gear wear: Operating below 2,500 RPM starves the gearbox of lubrication, accelerating wear. Many GO-300 failures trace back to chronic low-RPM operation by pilots who treated the engine like a standard direct-drive Continental.
• TBO limitation: The GO-300 has a 1,200-hour TBO, compared to 1,800 hours for the direct-drive O-300 in the 172. Overhaul costs for the GO-300 are high because the gearbox adds significant parts and labor. Expect $28,000-$35,000 for a GO-300 overhaul.
• Parts scarcity: GO-300 parts are increasingly difficult to source. Continental no longer actively supports the geared engine line, and the diminishing fleet means fewer cores in the overhaul pipeline. This is the strongest argument for the O-360 conversion.
• Prop strike implications: A prop strike on a geared engine requires teardown inspection of the reduction gearbox in addition to the standard crankshaft and case inspection. This makes prop strikes significantly more expensive on a GO-300.

Airframe ADs

The 175 airframe shares most ADs with the contemporary 172, including standard Cessna single-engine items like spar strap inspections and fuel system ADs. The airframe itself is sound and well-proven.

Pre-Buy Red Flags

1. Any GO-300 engine with unknown operating history — the engine may have been chronically run at low RPM
2. GO-300 nearing TBO with no conversion plan — overhaul costs may approach or exceed the airplane's value
3. Previous prop strikes on GO-300 airplanes with no documented gearbox inspection
4. Corrosion in the wing spar carry-through (common on all Cessna singles of this era)

Insurance for the Cessna 175 is straightforward standard fixed-gear coverage. Hull values are low enough that premiums are modest — expect $800-$1,200 annually for a private pilot with 200+ hours. The GO-300 engine does not trigger any specific underwriting concern beyond normal piston-single criteria, as insurers price based on aircraft category rather than engine type.

The low hull value of stock GO-300 aircraft means that liability coverage typically exceeds hull coverage in the premium calculation. See insurance-underwriting for category details.