Is the Raven I and Raven II overhaul kit the same?

No. The main difference between Raven I and Raven II kits is typically the system voltage. Early Raven I’s were 14v, all Raven II’s are 28v. Certain components like the actuator, hydraulic reservoir etc. are voltage-sensitive. This, alongside certain engine furnishings, makes the main difference between the two kits.

Does the Cadet really go to 2,400 hours?

Yes, the R44 Cadet’s overhaul interval is 2,400 hours (still 12 years on the calendar). The Raven I and Raven II remain at 2,200 hours.

Can you do paint and interior at the same time?

Yes. With the aircraft already down for overhaul, it’s the efficient time to refresh paint, interior, and avionics. We quote it together.

OVERHAUL · UPDATED AUG 4, 2026

Robinson R44 Overhaul Kits: Raven I, Raven II & Cadet

APEX HELICOPTERS, AUTHORIZED ROBINSON DEALER & SERVICE CENTER

The R44 reaches overhaul at 2,200 hours or 12 years (2,400 hours on the Cadet). The airframe overhaul replaces the same major components across Raven I, Raven II, and Cadet, what differs between variants is the engine and sometimes voltage.

What does an R44 overhaul replace?

The overhaul replaces all life-limited parts required per RHC and the FAA, plus certain parts listed in the RHC maintenance manual section 1.102. Another good guideline is the overhaul kit inspection instructions for the Raven I and Raven II.

What does the kit actually cost?

From the RHC maintenance-kit price list, effective January 1, 2026:

R44 Raven I overhaul kit (KI-4402), $205,000 + $20,650 core charge, $225,650 total with core
R44 Raven II overhaul kit (KI-4403), $207,200 + $20,150 core charge, $227,350 total with core
R44 Cadet overhaul kit (KI-4404), $203,600 + $20,650 core charge, $224,250 total with core
Engine build-up kit, O-540 (KI-4405) $6,790 · IO-540 (KI-4406) $6,960
Interior kit, R44 velour (KI-4407-1) $10,300 · leather (KI-4407-2) $11,500 · Cadet velour (KI-4408-1) $7,080 · leather (KI-4408-2) $7,520

Core charges are refunded when cores return to RHC within nine months. Bladder fuel tanks must be purchased unless previously installed. Kit prices are RHC list and change without notice, confirm current numbers with APEX, or request an estimate. Full breakdowns: R44 engine build-up kits and R44 interior kits.

Which engine, and what are the options?

The engine is the main difference between R44 variants: Raven I / Clipper I run the carbureted Lycoming O-540, Raven II / Clipper II the fuel-injected IO-540, and the Cadet a derated O-540. Either engine is handled three ways, separate from the airframe parts:

Overhauled exchange
Factory rebuilt
New

Engine choice has a significant effect on overhaul costs and lead time, contact APEX for current pricing and lead times. Lycoming overhaul guidance is published at lycoming.com.

Should I refresh the interior or avionics during overhaul?

Overhaul is the natural time to address an aging interior, glass upgrades, or air conditioning, because the aircraft is already down. We’ll quote those options alongside the overhaul so you can decide on one timeline. Older airframes may also have open service bulletins to clear (e.g. the bladder fuel tank SB) against your serial number, which Robinson lists in its safety notices and bulletins.

What does an R44 overhaul cost?

This answer depends largely on total time and condition of the aircraft. The overhaul is the perfect time to paint the aircraft, upgrade avionics or replace scratched windows. All these options add time and costs. For a rough guideline, in 2026 R44 overhauls are ranging between $300-$350k out the door, zero time. Weigh the spend against selling in the overhaul-or-sell guide.

Questions, answered

Is the Raven I and Raven II overhaul kit the same?: No. The main difference between Raven I and Raven II kits is typically the system voltage. Early Raven I’s were 14v, all Raven II’s are 28v. Certain components like the actuator, hydraulic reservoir etc. are voltage-sensitive. This, alongside certain engine furnishings, makes the main difference between the two kits.
Does the Cadet really go to 2,400 hours?: Yes, the R44 Cadet’s overhaul interval is 2,400 hours (still 12 years on the calendar). The Raven I and Raven II remain at 2,200 hours.
Can you do paint and interior at the same time?: Yes. With the aircraft already down for overhaul, it’s the efficient time to refresh paint, interior, and avionics. We quote it together.