The U.S. Marine Corps CH-53E Super Stallion is among a handful
of military helicopters available today that can move and re-supply
forces high in the mountains of Afghanistan. Like the lighter Army
Chinook, the three-engine, seven-blade 53E never was designed as
an air-assault platform, but its payload and range have made it
an asset in the Central Asian conflict.
The CH-53E is flying 20 percent more than a year ago, officials
said. This has accelerated the need for a service life extension
program (SLEP). A Marine Corps/Navy team currently is formulating
a CH-53E SLEP operational requirements document. Depending on the
outcome of the ORD, the services may decide to procure new aircraft
or begin the SLEP program as early as fiscal 2004. The remanufactured
or new-production helicopters would enter the fleet in 2012.
Sikorsky Aircraft delivered 180 CH-53Es to the Marines between
1981 and 1999. The service now has about 165 aircraft in active
and reserve squadrons. While the helicopters average 13 years old,
the earliest Super Stallions are passing 20 years in service. One
was retired early this year.
The current cost of operating the CH-53E is about $10,000 per flight
hour. The Marines expect that a new or remanufactured helicopter
would be less costly. Meanwhile, the heavy lift requirements of
the Marine air-ground task force have grown. The CH-53E was designed
to lug howitzers, light armored vehicles, or 16 tons of external
cargo from assault ships to the beach over a 50 nautical-mile radius
at sea level. But the new Marine Corps doctrine sets a 200 nautical-mile
radius. Afghan landing zones at 10,000 feet elevations show that
not all wars are fought under sea-level standard-day conditions.
The CH-53E SLEP (at various times called the CH-53X or CH-53 modernization)
could cut the operations and support costs of the CH-53E by about
25 percent, Marine officials estimated.
Main transmission beams, bulkheads, and vertical pylon components
give the existing CH-53E airframe a design life of about 6,000 flight
hours. Replacing those items to restore airframe life and increase
gross weight effectively would build a new helicopter. The ultimate
number of CH-53Es in the SLEP—whether they are remanufactured
or new production—is still to be determined.
Should a SLEP contract begin design work in 2004, the first remanufactured
CH-53E could fly by 2009. To avert an inventory shortfall before
SLEP deliveries build up, improvements may come in stages. The first
stage would give the CH-53E structural life improvements, an integrated
cockpit and an improved cargo handling system. The second would
permit a gross weight increase with more powerful engines and a
new main rotor system.
To sustain Marine squadrons, the SLEP could be preceded by new
aircraft—equipped with T64-GE-19 engines, a glass cockpit,
and a health-and-usage monitoring system.
The design of a new or rebuilt Super Stallion will be determined
by trade studies. Several improvements already were requested by
former Deputy Commandant for Marine Corps Aviation Lt. Gen. Fred
McCorkle. These include a new center fuselage, transition section
and tail-boom with structural enhancements that could increase gross
weight from 73,500 to 78,500 pounds. The CH-53E never was hardened
ballistically for air assaults in “hot” landing zones.
A new structure could incorporate armor protection around engines,
flight controls and other critical areas.
Performance at High Altitudes
The Marines want their heavy-lift helicopter to haul a 28,000 pound
Light Armored Vehicle over a 100 to 200 nautical-mile radius, taking
off at 3,000 feet on a 91.5 degrees F day. Under those conditions,
today’s CH-53E carries only 7,600 pounds over 200 nautical
High-and-hot performance of the Super Stallion is limited by available
engine power. With three General Electric T64-GE-416/416A turboshafts,
the 13,000 shaft-horsepower main gearbox of the CH-53E receives
only 9,700 shaft-horsepower at 3,000/91.5. While the CH-53E SLEP
will probably retain the present transmission with minor reliability/maintainability
improvements, it will introduce new engines probably chosen by a
Today’s T64-GE-416 engine is rated 4,380 shaft-horsepower
at sea level on a standard day and around 3,200 shaft-horsepower
high-and-hot. To provide more power at low cost, GE plans to grow
the -419 version of the engine now flying on Navy MH-53E minesweeping
helicopters. With hot section components from GE’s modern
commercial engines, the T64 growth engine would generate 5,370 shaft-horsepower
at sea level on a standard day and 4,728 shaft-horsepower at high
density altitudes. If required, the T64 could be modernized with
a full authority digital engine control (FADEC).
Rolls Royce proposes adapting the 6,200 shaft-horsepower AE1107C
engine of the Marine MV-22 to the CH-53E SLEP. The engine pro-vides
around 5,700 shaft-horsepower high-and-hot, and would give Marine
composite squadrons aboard amphibious assault ships a single large
turbo-shaft to maintain for two types of aircraft. The AE1107 already
has a FADEC and shares its core with the AE2100 turboprop now on
Marine KC-130J tankers.
Pratt and Whitney plans to offer a turbo-shaft derivative of its
new PW150 turboprop now flying on regional airliners. The 7,000
shaft-horsepower sea -evel engine would fill the CH-53E transmission
under high-and-hot conditions.
About 75 percent of the CH-53E SLEP lift improvement will come
from the new engines and 25 percent from an advanced main rotor.
Sikorsky has suggested an advanced rotor system. New all-composite
rotor blades scaled up from those on the S-92 medium lift helicopter
would eliminate the titanium spar of the present CH-53E blade, and
its maintenance-intensive pressurized blade inspection method, said
company officials. A new titanium main rotor head with elastomeric
center bearing element could supplant the oil-lubricated rotor-head
now on the CH-53E, cutting the number of parts in half.
The CH-53E main rotor hub is the single biggest maintenance cost
driver. Others include the main gearbox, rotor blades and swash
The cockpit of today’s CH-53E is a high-workload collection
of analog gauges made more crowded in recent years by the display
for a Raytheon AAQ-16 forward looking infrared (FLIR) sensor. Night-vision
goggles, FLIR and various navigation systems already give the 53E
a measure of night/adverse weather capability. However, the CH-53E
SLEP promises a databus-integrated avionics suite with multifunction
displays to manage aircraft systems and modern communications and
navigation avionics. A glass cockpit could help shrink the current
instrument panel and improve visibility.
Common avionics is a feature found in other Marine aircraft today.
The MV-22 has a Boeing-integrated glass cockpit with Honeywell displays.
The modernized AH-1Z attack helicopter and UH-1Y utility helicopter
share a common avionics suite integrated by Northrop-Grumman. The
new KC-130J tanker has a glass cockpit integrated by Lockheed Martin.
Whatever the source and integrator, a new glass cockpit with digital
connectivity should give CH-53E crews better situational awareness,
officials said. The Marines expect an open SLEP avionics architecture
to accommodate future joint-service radios and the so-called TADIL-J
A CH-53E SLEP, additionally, could, for the first time, provide
the Super Stallion with infrared suppressors and an integrated aircraft
survivability suite. Improvements are also expected in the internal
and external cargo handling systems.
Separately from the Marine Corps CH-53E program, the Navy has yet
to decide the future of its MH-53E Sea Dragon minesweepers. Should
the Navy elect to continue to perform the airborne mine countermeasures
mission with dedicated aircraft, the big Sea Dragons could take
advantage of the engine and dynamic improvements used on the Marine