Apache to Diamond Geronimo
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Whether you are an individual looking for a reliable, spacious business class aircraft or a
flight school looking for an economical, sturdy multi-engine trainer, the versatile Piper
Geronimo can meet all your needs.
Powered by Lycoming 180 HP engines, this six-seat aircraft has the ability to take off and land
on shorter fields easily clearing 50ft obstacles.
A range of 1025 miles makes the Geronimo convenient for longer trips.
Tens of thousands of dollars were spent on engineering to obtain the optimum performance
from the Apache airframe. Every change was meticulously designed and mated to the basic
aircraft. Rigorous examination, with an abundance of in-flight testing, was completed on each
innovation before submitting it to the FAA for approval. The thoroughness of the program is
attested to by the complete lack of Airworthiness Directives recorded against the Geronimo
during the 30 years it has been on the market.
The PA23 series has no history of spar breakage. The spar is actually a huge I-beam that runs
thru the center of the wings and is joined in the center belly area. These aircraft are over-built
and very rugged. The fuselage is 4130 steel tube framed and also uses aluminum stringers
and ribs for extra strength. The use of both aluminum & steel (dissimilar metals) required
Piper to zinc-chromate the complete structure inside and out at the factory. For that reason
it�s hard to find a PA23 with any significant corrosion. The weak spots have historically been
in the tail, rudder/elevator areas.
When we overhaul an Apache airframe, we completely strip the aircraft inside and out. All of
the tail surfaces are removed including the vertical and horizontal stabilizers. We have STC
SA2793SW which is a rudder bracket reinforcement, SA4007SW which is a structural
improvement parts kit for the flaps and elevators. The whole aircraft is powerwashed inside
and out, all surfaces are inspected. The landing gear gets updated (much-stronger) drag
links, the tail system attach areas get a doubler added and all new attachment hardware
before the tail components are reinstalled. All hoses are replaced, control surface
hinges/bearings…all hydraulic components overhauled, all moving parts in the whole
airframe get re-bushed or bearings replaced as applicable….the list gets pretty long. In short,
we are very thorough with our airframe overhauls.
Montana Diamond Aire has owned the STC�s that make up this conversion since 1996. In
addition to performance enhancing aerodynamic cowls, extended nose, windshield fairings,
wheel well doors that fully enclose the main gears and flap gap seals, we offer a host of
convenience mods such as third side windows and inflatable door seals
To see how the Piper Geronimo out performs other multi-engine aircraft please note the
comparison charts below.
Standard Features Include:
Lycoming O-360 A1D 180 HP Engines
Hartzell HC-C2YK-2RB-7666A2 Props
Rams Horn Control Wheels
Oil Warning Lights
Southwind 20,000 BTU Heater
Flap Gap Seals
One Piece Windshield
Hoerner-Type Wing Tips
Introducing the Next - Generation Piper Geronimo!
Powered by 2 factory-new Fuel Injected Lycoming IO-360
Roller Cam Equipped 200 HP Engines will be completed by
the end of April. Check our blog at
www.diamondaire.wordpress.com for test flight reports.
This will be the first 200 Hp Roller Cam-equipped model in
Montana Diamond Aire holds the exclusive STC for this
engine upgrade for the Piper Geronimo.
We currently have Piper Apache airframes available for
conversion to Piper Geronimo. Order your conversion today and
be in the air in early 2010!
"What a difference! Everything wrong with the Apache was right with the
Geronimo. It was a far safer airplane to fly. The single-engine performance was
outstanding and it was easy to fly. The Geronimo flies faster, climbs better, is far
more efficient and looks like a million bucks, but only costs about a third of that. If
you believe you would like a very nice inexpensive twin, search out a Geronimo
converted Apache. This is an outstanding light twin aircraft."- Norm Goyer, Aircraft
Marketplace April 2009
" It�s very important to note that the full conversion results in an airplane that�s
superior to the original one in virtually all respects. The Piper Geronimo is, after all,
a fully remanufactured, ground-up and rebuilt airplane, not just a fancy name for
an engine swap. It�s about as close as you can come to new, but at significant,
savings. In addition to range, handling and performance improvements, the full
Geronimo conversion turns the Apache into a six-seater "- Bill Cox, Plane and Pilot
Press Reviews for Our Geronimo Conversion
Montana Diamond Aire Inc.
Apache Modification Aircraft Corp.
1893 Airport Road
Kalispell, MT. 59901
John Talmage, CEO