PT6A-27 and PT6A-28: Understanding the Two Variants

The PT6A-27 and PT6A-28 are closely related members of the PT6A engine family, sharing the same 680 shaft horsepower output and core gas generator design. They are often grouped together in the secondary market because of their similar power ratings, but they are distinct variants with different Type Certificate approvals, different airframe applications, and different installation configurations.

The PT6A-27 was certified earlier and powers a broader range of aircraft, including the Cessna 208 Caravan (early production), Pilatus PC-6 Porter, de Havilland DHC-6 Twin Otter, and several agricultural and utility platforms. The PT6A-28 was developed for twin-engine light transport applications, most notably the Cessna 402C and Piper PA-31 Navajo Chieftain, with different reduction gearbox configurations and accessory pad layouts suited to those airframe installations.

Neither variant is interchangeable with the other without an FAA-approved STC or engineering order. Buyers must confirm the required variant against their specific aircraft Type Certificate Data Sheet before initiating any sourcing process. UTP verifies variant-to-airframe applicability against aircraft serial number and configuration before presenting any options.

PT6A-27 vs PT6A-28: Specification Comparison

The table below provides a direct side-by-side comparison of the PT6A-27 and PT6A-28 for buyers evaluating their specific requirements.

Specification	PT6A-27	PT6A-28
Shaft Horsepower	680 shp	680 shp
TBO	3,600 hours	3,600 hours
Primary Airframes	Cessna 208 Caravan (early), Pilatus PC-6, DHC-6	Cessna 402C, Piper PA-31 Navajo Chieftain
Typical Application	Single-engine utility, cargo, agricultural	Light twin-engine transport
Secondary Market Depth	Very high — large installed fleet	Moderate — smaller installed fleet
Core Availability	Strong; consistent supply from fleet retirements	Available; sourced through dealer networks
Interchangeable?	No — STC or engineering order required	No — STC or engineering order required

PT6A-27 and PT6A-28 Airframe Applications

PT6A-27 Approved Airframes
The PT6A-27 powers a broad range of utility, cargo, and multi-role aircraft. Key approved platforms include:

• Cessna 208 Caravan: early production; later Caravan variants use the PT6A-114 series
• Pilatus PC-6 Porter: Swiss STOL utility aircraft widely used in cargo, parachuting, and bush operations
• de Havilland Canada DHC-6 Twin Otter: a primary regional commuter and floatplane platform
• Britten-Norman BN-2 Islander: light twin commuter and utility
• Multiple agricultural spray aircraft platforms approved under type certificate

PT6A-28 Approved Airframes
The PT6A-28 was designed for light twin-engine transport applications:

• Cessna 402C Businessliner/Utililiner: primary application; widely used in regional cargo and charter
• Piper PA-31 Navajo Chieftain: twin-engine business and charter transport
• Additional twin-engine platforms as specified in the PT6A-28 TCDS

How UTP Sources PT6A-27 and PT6A-28 Engines

PT6A-27 secondary market availability is among the strongest in the PT6A family. The large installed base of Cessna 208 Caravans, Pilatus PC-6 aircraft, and DHC-6 Twin Otters generates consistent supply of run-out cores, serviceable mid-time units, and freshly overhauled engines. For common conditions and configurations, UTP typically identifies qualified PT6A-27 options within 5 to 15 business days.

PT6A-28 sourcing volume is lower due to the smaller installed fleet, but serviceable and overhauled units are regularly available through UTP established supplier and dealer networks. Lead times for PT6A-28 units may be slightly longer than PT6A-27, particularly for specific condition requirements. AOG situations for both variants receive priority handling. Contact UTP directly with your variant, serial number, required condition, and timeline for current availability.

PT6A-27 and PT6A-28 Condition Guide

New / Zero-Time

Factory-new PT6A-27 and PT6A-28 engines are available on a limited basis, primarily as new surplus units. New factory production of the PT6A-27 has wound down as later variants replaced it in current-production aircraft, making new units increasingly scarce. New surplus units require careful storage records review before accepting for installation.

Serviceable MID-TIME

Operated PT6A-27 and PT6A-28 engines with documented TSN and TSO remaining. Value is determined by remaining TBO hours, logbook integrity, AD compliance status, and the condition of the hot section verified through a borescope inspection. Given the strong overhaul infrastructure for these variants, mid-time units offer strong value for operators with near-term budget constraints. A borescope report from an independent A&P mechanic is standard due diligence.

Overhauled / Zero-Time Since Overhaul

PT6A-27 and PT6A-28 engines restored to serviceable or new-limits condition by an FAA-certificated repair station with appropriate PT6A ratings. A zero-time overhaul ships with a new FAA Form 8130-3 and resets both TSN and TSO. The PT6A-27 is supported by a robust overhaul industry due to its large installed fleet, giving buyers multiple qualified overhaul facility options. Confirm current FAA repair station certificate and PT6A-27 or PT6A-28 specific ratings before accepting any overhauled unit.

Run-Out / Core

PT6A-27 cores are consistently available from fleet retirements and scheduled overhaul events. Core value depends on variant, TSN/TSO, logbook completeness, and physical condition of the hot section and gearbox. PT6A-27 cores are accepted by UTP as trade-in toward a serviceable or overhauled replacement unit. Core exchange programs reduce out-of-pocket acquisition cost for operators managing budget constraints.

What PT6A-27 and PT6A-28 Buyers Most Often Get Wrong

The most common error specific to these variants is assuming PT6A-27 and PT6A-28 interchangeability because of the matching 680 shp power rating. The shared power output creates a false impression that the two engines are equivalent, but they are not. Their airframe approvals, gearbox configurations, and installation requirements are distinct. Buying a PT6A-28 for a PT6A-27 application—or vice versa—creates an immediate airworthiness finding and cannot be corrected without a specific STC or engineering order.

The second common mistake is undervaluing the PT6A-27 logbook history for aircraft participating in agricultural operations. Agricultural PT6A-27 applications accumulate hours under more demanding operating conditions, and the hot section condition at a given TSO may differ significantly from an equivalent-hour engine in utility or cargo service. Always request a current borescope inspection report regardless of documented hours when sourcing a PT6A-27 from agricultural service.

PT6A-27/28 Engine Buying Checklist

• Confirm exact variant, PT6A-27 or PT6A-28, against aircraft TCDS and serial number
• Verify complete and continuous logbook records from new with no missing entries or unexplained gaps
• Request full AD compliance record—verify all applicable directives addressed with no open items
• Request current borescope inspection report, particularly if aircraft was in agricultural service
• Confirm overhaul facility holds current FAA repair station certificate with PT6A ratings
• Verify FAA Form 8130-3 is present, current, and matches the engine serial number exactly
• Confirm all STC documentation transfers with the engine if any modification has been applied

PT6A-27 and PT6A-28 Engine Pricing: Market Overview

PT6A-27 and PT6A-28 engines trade at the entry-to-mid range of the PT6A price spectrum, reflecting their 680 shp power class and the depth of secondary market supply for the PT6A-27 in particular. Pricing is influenced by condition class, remaining TBO, logbook quality, and the specific overhaul facility involved for overhauled units.

Market pricing as of Q2 2026. Prices vary by condition, remaining TBO, and current market availability.

Condition	PT6A-27 Typical Range	PT6A-28 Typical Range	Notes
Run-out / Core	$40,000 – $80,000	$40,000 – $75,000	Exchange value; depends on logbook completeness and hot section
Serviceable Mid-Time	$90,000 – $180,000	$85,000 – $170,000	Exchange value; depends on logbook completeness and hot section
Overhauled / Zero-Time	$150,000 – $250,000	$140,000 – $230,000	Confirm overhaul facility ratings and overhaul scope
New / Factory New	Market on request	Market on request	Increasingly scarce; storage records verification required

The PT6A-27 typically prices at a modest premium over the PT6A-28 at equivalent condition levels, reflecting stronger demand from the larger Cessna 208 Caravan and Pilatus PC-6 operator base. Total cost of ownership, factoring in remaining TBO hours, overhaul history, and AD compliance status, is a more reliable guide than acquisition price alone.

How to Buy a PT6A-27 or PT6A-28 Engine from UTP

Start with a direct inquiry. Provide your aircraft make, model, serial number, required variant (PT6A-27 or PT6A-28), preferred condition, and timeline. UTP confirms variant-to-airframe compatibility, initiates sourcing through its global network, and presents qualified options with full documentation details before any commitment is required.

Support includes:

• Variant compatibility confirmation against aircraft TCDS and serial number
• Logbook and documentation review on every option before presentation
• Coordination of pre-purchase borescope inspections when required
• Core exchange valuation for operators trading in a run-out or time-expired engine
• AOG expedite handling for time-critical sourcing requirements

All PT6A-27 and PT6A-28 engines ship with complete logbook copies, current FAA Form 8130-3 airworthiness documentation, and an AD compliance summary. Export documentation and EASA Form 1 equivalency paperwork available for international buyers.

Frequently Asked Questions—PT6A-27 and PT6A-28 Engines