STCs for X-Range Meridian and Beech 300 series

Atting March, 2025 – German propeller manufacturer MT-Propeller have obtained new supplemental type certificates for the installation of their products in two different aircraft models.

First, there is now the FAA approval (in addition to the EASA approval) of Piper’s M500 Meridian by MT-Propeller as presented at last year's Aero.



The replacement of the original PT6A-42A propeller turbine with a PT6A-135A propeller turbine follows MT-Propeller's declared goal of making General Aviation aircraft quieter and more efficient with new propeller systems - in the case of the Piper M500 Meridian with the additional replacement of the engine.

The replacement of the original PT6A-42A propeller turbine with a PT6A-135A propeller turbine follows MT-Propeller's declared goal of making General Aviation aircraft quieter and more efficient with new propeller systems - in the case of the Piper M500 Meridian with the additional replacement of the engine.



The advantages of the engine replacement are:

More Efficiency:

RANGE: Max. range with max fuel (ISA, MTOW, no wind, one pilot, 45 min fuel reserve)

203 KTAS cruise speed: 1340NM (2479km) @ 30000ft

203 KTAS cruise speed: 1290NM (2387km) @ 28000ft

240 KTAS cruise speed: 1160NM (2146km) @ 28000ft

258 KTAS cruise speed: 960NM (1776km) @ 25000ft

Reduction of Maintenance cost:

Changing the engine family from the mid-size to the small-size category, makes an impressive difference in operating costs.

Direct cost per mileage will be similar to the PA46-350P Lycoming-powered Mirage, but with a top speed of up to 260 KTAS @ 30,000 ft.

Noise reduction:

The new engine has a speed of 1900 rpm compared to the original speed of 2000 rpm.

The certified outside noise is reduced from the original 74,9 db(A) to 66,9 db(A) for 1.999 kg.

The inside noise has also been reduced.

The 5-bladed propeller is mandatory for this STC, but in case the 5-blade Quiet Fan Jet MTV-27 propeller is already installed, it can also be used on this conversion.

The MT-Propeller STC Kit contains the following parts:

1 new engine P&W PT6A-135A

1 new propeller MTV-27-()/CFR203-58d

1 new set of exhaust pipes

1 new set of airbox parts

1 new bracket set for the engine power

control interface

Not included but minimum needed: The Garmin EIS System

Then, there is also news on STCs issued by, both the FAA and EASA for Beechcraft’s 300 series with the 7-blade Silent 7 MT-Propeller.

MT-Propeller Entwicklung GmbH has received the FAA STC SA11914IB and the EASA STC 10085161 for the installation of the 7-blade Silent Seven Propeller MTV-47-1- ( )-C-F-R(P)/CFR260-361( ) on the Textron Aviation Inc. Beech King Air 300, 300LW, B300, B300C series powered by two Pratt & Whitney Canada PT6A-60A propeller turbines: for Models 300, 300LW, B300, B300C PT6A-67A: optional for Models B300 und B300C. The Blackhawk XP67 conversion is also covered by this STC.



MT-Propeller Entwicklung GmbH received STCs issued by FAA and EASA for the installation of the 7-blade Silent Seven Propeller.

The 7-blade Silent 7 propeller was introduced to the General Aviation market in year 2020 when successfully certified on the Pilatus PC-12.

More than 130 PC-12 are already flying with this high-performance 7-blade propeller.

In year 2023 the flight testing started to certify this advanced propeller system also for the Beech King Air 300 series to benefit from the Silent 7 MT-Propeller.

MT-Propeller Vice President Martin Albrecht says, that the installation features the following advantages:

- General performance improvement (8% take-off & climb)

- No propeller speed restrictions on ground while operating in low idle

- Lower ITTs at high altitude; allowing a top speed increase up to 6 KTAS or longer engine life.

- Unbeatable esthetic ramp appeal

- Significant cabin noise and vibration reduction

- All models comply with the strict German noise regulations 2010– „Landeplatz Lärmschutz Verordnung“ for unrestricted airport operations in Germany and other European Countries.

Due to the smaller diameter the 7-blade MT-Propeller for the Beech King Air 300 Series has more ground clearance for less blade tip erosion and FODs. The long-time proven MT-Propeller natural composite blades provide significant inside and outside noise reduction. They have no life limitation and are repairable in case of a FOD.

They also provide best vibration damping characteristics for almost vibration free propeller operation and have bonded on nickel alloy leading edges for superior erosion protection of the blades.

About MT-Propeller



MT-Propeller is the world leading natural composite propeller manufacturer with 30 certified propeller models from 2-blade to 7-blade hydraulically controlled variable pitch propeller, for engines producing up to 5000hp, and 2-blade to 4-blade electrically controlled variable pitch propeller, for engines producing up to 350hp as well as two blade fixed pitch propellers.

The high performance, light weight and durable MT-Propellers can be used on aircraft with piston engines and propeller turbines, as well as on airships, wind tunnels and hovercraft. MT-Propellers can be developed for nearly every aircraft type from motor gliders to regional airliners.

Fulfilling the highest certification requirements they are also supplemental type certified on Part 25 aircraft.

MT-Propeller is holder of over 220 STCs worldwide and OEM supplier for more than 90% of the European Aircraft Industry as well as 30% of the US Aircraft Industry. More than 33 000 propeller systems with more than 115 000 blades are in service. 180 Million fleet hours where already performed on MT-Propellers.

With the longest industry TBO of 4500 hours or 6 years for the 5-bladed turbo prop MT-Propeller has proven the reliability over years.

A factory certified network of 62 service centers, provides best service and maintenance all over the world.

MT-PROPELLER Entwicklung GmbH
Airport Straubing-Wallmuehle
D-94348 Atting - Germany
phone: +49-(0)9429-9409-0
fax: +49-(0)9429-8432
sales@mt-propeller.com
www.mt-propeller.com