August 24th - 30th, 2004 -
Flight InternationalAugust 24, 2004
Based on the Alenia G222 and the C-27A operated by the US Air
Force in Central America, the C-27J Spartan represents a
significant enhancement of an already capable tactical transport.
Offered by the Lockheed Martin Alenia Tactical Transport Systems
(LMATTS) joint venture, the C-27J follows the route set by the
C-130J in taking a proven design and adding improved avionics and
propulsion. Rather than develop unique systems for the Spartan,
LMATTS borrowed them from the C-130J. Development time and costs
were minimised as proven systems were readily available, and life
cycle costs should be reduced as spares commonality with the C-130J
ensures a readily available parts pool. The benefits for operators
of both the C-130J and C-27J will be even greater, as common
avionics and systems will reduce transition-training costs, and may
allow for cross-crew qualification.
The C-27J programme was launched in September 1997. The first
prototype, used for testing the Rolls-Royce AE2100D2 engines and
Dowty R-391 six-blade propellers, flew in September 1999. The
second aircraft flew in May 2000, incorporating the new avionics.
The third and final development aircraft, representing the baseline
model, flew in September 2000. The C-27J received civil
certification in June 2001 and military qualification six months
later.
With production ramping up for delivery of the first of 12
aircraft to the Greek air force later this year, Flight
International was invited to fly the Spartan at Alenia's Turin
production and test facility.
The Spartan's true strength is apparent on the ramp; it is not a
small aircraft. While slightly shorter than its most direct
new-build competitor, the EADS Casa C-295, the C-27J has a larger
useable cargo volume. The cargo compartment is 2.45m (8ft) wide at
its flat floor and 3.33m at it widest point. The large diameter
allows a utility vehicle to be driven directly on and off without
any modifications or disassembly. The size advantage also carries
over to palletised cargo loads. Assuming standard 2.24m-wide
pallets, the Spartan can carry 44.1m3
(1,560ft3) of cargo, compared with the C-295's
37.4m3, says LMATTS. These pallets are the same height
(2m) as those carried by larger transport aircraft. Pallet
compatibility allows cargo to be transferred directly to the
Spartan, not broken down and repalletised as may be required for
loading into a smaller aircraft. For air-dropped cargo, the C-27J
can carry up to 6t of material on a single drop, 9t on multiple
runs, while the C-295 is limited to 2t, says LMATTS.
Jump cadence
The large cargo compartment also carries dividends when
transporting troops. The C-27J can carry up to 68 troops in an
optional high-density configuration, based on a 460mm (18in) seat
width. For the paradrop mission, the aircraft can carry 46
paratroopers, seven more than the C-295 can reasonably carry, says
LMATTS.
The C-27J's large cargo compartment has greater headroom,
allowing heavily laden paratroopers to stand erect as they shuffle
to the door. The dual exit doors on the C-27J are also larger than
those on the C-295 and should allow for rapid exiting of the
aircraft. Tactically, the higher the jump cadence the closer the
paratroops will be when they hit the ground, thereby increasing
combat effectiveness.
The Spartan was developed as a military aircraft and its
17,500kg (38,500lb) operating empty weight is markedly heavier than
that of the civil-derived C-295's. The extra weight yields a robust
aircraft with a three-spar wing. LMATTS says the Spartan's aluminum
structure is more damage-tolerant than composites and easier to
repair in the field. In addition, military cargo tends to be denser
than civil freight, requiring high floor strength. The Spartan's
cargo floor has a strength of 5,000kg/m (3,400lb/ft) (along the
length of the compartment), superior to the C-295's 1,000kg/m and
slightly better even than the C-130's, says LMATTS. In addition,
the C-27J can carry any cargo further than the C-295: according to
LMATTS the Spartan can carry 7,000kg a distance of 3,060km
(1,650nm) at its basic and tactical MTOW, while the C-295 can carry
the same load over 1,350km.
Pre-flight inspection of the Spartan, the developmental baseline
aircraft, was conducted by Alenia test pilot Agostino Frediani.
Externally, the aircraft closely resembles the G222 and C-27A, with
the exception of the 4.11m-diameter six-blade composite,
scimitar-shaped propellers, which are the same as those on the
C-130J. The R-R engines put out 4,635shp (3,455kW) and are nearly
identical to those on the updated Hercules. When viewed from
behind, the propellers turn clockwise, making the critical engine
the left one. As the rudder and vertical stabiliser are essentially
unchanged from the C-27A, increased rudder power was required to
keep minimum control speed at desired levels.
Seventeen vortex generators were added to the left-hand side of
the vertical stabiliser just forward of the rudder. These energise
the airflow over the rudder, increasing its effectiveness when
deflected to counteract yawing moments generated by an engine
failure.
Access to the aircraft is through the forward entry door with
its integral steps. The flightdeck is quite spacious with 16
windows. Eight shoulder-height windows, four per side, provide an
excellent field of view (FoV), while the four floor-level windows
gave a direct view of the ground. Four ceiling-mounted windows
enhance the overall FOV, while allowing for clearing of the flight
path when manoeuvring at high angles of bank.
Like the C-130J, the C-27J's forward instrument panel is
dominated by 180 x 205mm (6 x 8in) displays, of which the Spartan
has five: two multifunction displays in front of each pilot and one
centre-mounted. Each pilot has primary flight and navigation
displays, with the centre screen displaying engine parameters and
warning information. Dual autopilots are controlled via a
glareshield-mounted panel. Aircraft system controls, mounted on the
overhead panels, lend themselves to intuitive operation.
Cool start
An external-power cart was connected to our aircraft and the
dual global-positioning/inertial-navigation units aligned in less
than 4min. The Hamilton Sundstrand auxiliary power unit (APU),
mounted in the left landing-gear sponson, provided an air source
for engine start. If the APU is inoperative an external air cart or
even another Spartan can be used to start the engines. The engines
were started one at a time, the full-authority digital engine
control (FADEC) metering fuel to ensure a cool start. Before-taxi
check items were rapidly accomplished and consisted primarily of
testing the propeller overspeed protection system. Frediani
released the parking brake and used the nosewheel steering system's
left sidewall-mounted tiller to navigate the taxiways to Turin
Caselle's runway 36 for departure.
With an operating empty weight of 18,803kg and 3,606kg of fuel,
our take-off weight of 22,409kg was well below the maximum of
30,500kg. Once aligned on the runway, Frediani gave me control of
the aircraft for the take-off. I released the toe brakes and
advanced the throttles to the take-off detent. The FADECs
stabilised the engines at 4,700shp. During the initial part of the
take-off roll Frediani used the nosewheel steering to track
centreline, while I applied right rudder to counteract the
propeller P-factor. At 60kt (110km/h) indicated airspeed Frediani
released the tiller, and rudder alone was used to track
centreline.
At 91kt, less than 15kg of yoke force was required to establish
the initial take-off attitude. With the flaps set to position "2"
the Spartan leapt off the runway after a ground run of less than
280m. At maximum take-off weight and standard sea-level conditions,
LMATTS quotes a ground run of 580m. Once airborne a pitch attitude
approaching 20° was required to maintain the initial climb
speed of 130kt. Gear and flap retraction caused little change in
pitch forces as the pitch attitude was reduced to capture a climb
speed of 170kt.
Cargo drop
Hand-flying the aircraft during a climb to 8,000ft (2,440m)
above mean sea level, I did a series of gentle manoeuvres to get a
feel for the aircraft. Pitch and roll forces were well harmonised,
with roll response fairly crisp for a transport-category aircraft.
Once level, I engaged the autopilot and autothrottle. Rate of climb
to level off had averaged roughly 3,000ft/min (15.2m/s).
Frediani had programmed the mission computer to simulate a cargo
drop and the autopilot followed its guidance along the planned
route. The simulated drop zone was an airfield around 90km (60
miles) south of Turin. Like the C-130J, the Spartan does not have a
navigator; the GPS/INS and ground-mapping radar combine to allow
the two pilots to accurately find the drop zone.
At 180kt the ramp was lowered in preparation for the drop. A
slight reverberation was felt with the ramp down, but ambient
flightdeck noise was not markedly louder than with it closed. The
mission computer commanded a descent to a drop altitude of 1,500ft
above ground level and appropriate speed reductions as the aircraft
approached the initial point (IP) leading to the computed
air-release point. Flaps were set to "3" and speed further slowed
to 105kt before reaching the IP. Once past the IP I disengaged the
autopilot and autothrottle to hand-fly the drop run. The mission
computer provided the flight director (FD) with wind-corrected
guidance to the air-release point for an aimpoint at the centre of
the airfield. I found the lower sidewall windows useful for
confirming that the computer-derived release point made sense in
relation to the real world.
After completing the drop run the ramp was closed and flaps
retracted. Once the aircraft was in a clean configuration I engaged
the autopilot and autothrottle for a climb to 8,000ft. Once level
at 8,000ft the autopilot precisely maintained 200kt indicated air
speed. Total fuel flow was 966kg/h and the 22,160kg aircraft
maintained 228kt true airspeed with a static air temperature of
14°C (57°F/ISA +15°C). For high-speed transit LMATTS
projects a maximum true airspeed of 315kt for a 29,000kg
gross-weight aircraft (95% MTOW) at 16,000ft on a standard day.
I next used the flight-level change mode of the autopilot to
initiate a descent to 2,500ft (1,500ft AGL). While the autopilot
and autothrottle did an excellent job of maintaining flightpath and
airspeed, it did not trim the rudder. The conventional ball-type
slip indicator on top of the outboard display, where the PFD is
usually presented, allowed me to keep the aircraft in trim as
varying power levels required corresponding trim changes. Once
level at 2,500ft a total fuel flow of 1,110kg/h was required to
hold 220kt (208kt indicated). Trimmed, with autopilot and
autothrottle off, the aircraft was quite stable, allowing me to fly
it hands off. The ride at low altitude, albeit on a calm day over
level terrain, was quite smooth.
To avoid simulated small-arms fire along our route, I jammed the
throttles to the maximum-continuous detent and started a rapid
climb. The initial climb rate was in excess of 4,000ft/min as the
airspeed was bled off to obtain an optimum value of 170kt
indicated. Rate of climb from 10,000ft to 15,000ft was roughly
3,000ft/min. While one would do well to avoid hostile fire, the
Spartan can be equipped with optional armour plating and an
anti-deflagration inerting system for the fuel tanks.
Having climbed out of the small-arms threat envelope, we were
now more vulnerable to missile threats. The Spartan can be equipped
with radar and or laser warning receivers, as well as a missile
approach warning system and chaff and flare dispensers.
Additionally, a directional infrared countermeasures system and
towed decoys are available.
Should these systems fail to defeat the missile, the Spartan is
fairly manoeuvrable, with 3g attainable in a large portion
of the flight envelope. Earlier, I found that at a gross weight of
22,000kg, slightly over 2.5g could be sustained at 200kt
and 5,000ft. During manoeuvres at 5,000ft, pitch forces were fairly
low. While load factor can be read on the PFD, the aircraft
provided good tactile cues as to g loading. Pulling through
2.8g light airframe buffet signalled the approach of the
3g limit at tactical weight. At sea level and MTOW, LMATTS
quotes a maximum sustained capability of 3.5g for the
Spartan. The conventional boosted flight controls will allow the
pilot to exceed the published limits and "bending it" may be
preferable to missile impact.
Simulated loss
Next, while still at 15,000ft, Frediani shut down the left
(critical) engine to simulate its loss. Sensing an engine failure
the FADEC automatically signalled the propeller control unit to
feather the left propeller, a feature that could substantially
reduce pilot workload during a critical phase of flight. At 140kt
and maximum continuous power, the 21,500kg aircraft was able to
maintain level flight in a 40°-banked turn. At this weight
LMATTS quotes a one-engine-inoperative ceiling of roughly 24,000ft
pressure altitude. Less than 35kg of rudder force was required for
co-ordinated flight and around three-quarter deflection of the
rudder trim zeroed out pedal forces. While I did not explore the
Spartan's single-engine handling qualities at speeds lower than
140kt, the aircraft was quite responsive and had significant excess
power at this intermediate gross weight and medium altitude.
Frediani used bleed air from the operating engine to restart the
left engine. Once both engines were running the power was set to
idle for a clean configuration power-off stall. In level flight the
Spartan was decelerated at about 1kt/s. The stick shaker activated
at 112kt. At shaker speed, control effectiveness in all three axes
was good. Slowing just below shaker speed caused the onset of light
airframe buffet. The aircraft was further slowed until the yoke was
at the aft stop. The aircraft settled into a wings-level descent at
104kt. Recovery to normal flight was accomplished by releasing yoke
back pressure and advancing the throttles.
The second and final stall was also in a clean configuration,
but this time the throttles were set to a mid-range position of
2,600shp. This power-on stall demonstrated the effect of
propeller-wash flow over the wing. The stick shaker in this
condition did not activate until 101kt. As before, light airframe
buffet was felt as the aircraft slowed below the shaker speed. With
the yoke at the aft stop the aircraft was in a 20° nose-high,
wings-level descent at 94kt. Recovery to normal flight was again
accomplished by lowering the nose and advancing the throttles. The
two clean-configuration stalls showed the Spartan to be docile at
slow speeds, while illustrating the effect power setting can have
on the stalling speed.
On our return to Turin Caselle, Frediani demonstrated the
Spartan's steep descent mode. This is armed by push buttons on the
throttles and allows the FADEC to schedule reduced idle torque: by
varying the propeller pitch, a slightly negative thrust can be
commanded for a rapid descent. Pulling both throttles to idle
engaged the steep descent mode, with the word "STEEP" displayed
below the power display for each engine.
At 130kt the aircraft stabilised in a 10° nose-down flight
path from 15,000ft. Initially the rate of descent was around
2,500ft/min, increasing to 3,000ft/min by 4,000ft as the FADEC
allowed more negative thrust. The steep descent mode may help the
Spartan get into hot landing zones by allowing it to stay above the
threat posed by small-arms fire until close to the field.
Ergonomic error
Once level at 4,000ft en route to Turin Caselle, I used the
Northrop Grumman APN-241 colour radar to paint the airfield. At
75km from the field, the runway and surrounding roads were clearly
displayed in shades of green. Returns from targets such as
buildings were presented in colour. The radar cursor could be moved
via a control handle on the centre console.
While the cursor itself was easy to move and control, I felt the
handle was located too far aft on the console for comfortable use
while at the co-pilot's position. In addition to an excellent
ground mapping capability, the radar also has a beacon mode.
Pathfinder personnel place a transponder at the drop zone. The
beacon's distinctive code gives an easily identifiable return on
the radar display, making drop zone location an easy task.
In preparation for an instrument landing system approach,
Frediani removed the radar display from the right inboard screen
and replaced it with a map display. This showed approaching
waypoints as well as TCAS traffic in the terminal area. The flight
director's guidance allowed me to easily capture and track both the
localiser and glideslope. With the flaps set to "2" for a
touch-and-go manoeuvre, I slowed the aircraft to 120kt on short
final.
As could be expected, the digitally controlled engines and
propellers allowed target airspeed to be precisely maintained. At
10ft above the runway I retarded both throttles to idle and raised
the nose several degrees for the flare manoeuvre. The Spartan
settled on to the runway less than 30m beyond my aimpoint. After
lowering the nosewheel to the runway I advanced the throttles to
the take-off detent. At 120kt I rotated the aircraft and
established a climbing left-hand turn to downwind.
The last approach and full-stop landing was again to runway 36,
but with the flaps set to "4", their most extended position. A
5° visual glidepath was intercepted and an airspeed of 105kt
maintained. Rate of descent on this steep approach was 1,000ft/min.
At 20ft above the runway I retarded the throttles to idle, and
raised the nose slightly. The aircraft touched down in a 500ft/min
sink on the aimpoint, just beyond the threshold.
The four trailing-arm main landing gear readily absorbed the
impact and the spoilers automatically deployed to dump lift. I
moved the throttles to the maximum reverse position, allowing the
large propellers to slow the 21,185kg aircraft. Frediani applied
maximum toe brakes and the aircraft was stopped after a ground run
of less than 300m. Total landing distance would have been roughly
500m. Frediani took control of the aircraft for the taxi back to
Alenia's test ramp. After a 2min cool-down period, both engines
were shut down and we deplaned.
The C-27J is a complete tactical airlifter. Derived from the
G222/C-27A, its upgraded avionics and propulsion system are shared
with Lockheed Martin's C-130J and significantly enhance its
capabilities. The large cargo compartment allows for drive on and
off of utility vehicles and the direct transfer of standard-size
pallets from large transport aircraft.
Combat survivability
The upgraded avionics allow two pilots to successfully conduct
air-drop operations, a task that used to require three flightdeck
crewmembers. Rugged construction, redundant systems,
self-protection systems and a high power to weight ratio combine to
enhance combat survivability.
The baseline Spartan flown by Flight International can
be further enhanced with the addition of a head-up display and
in-flight refuelling capability. With 24 firm orders from the Greek
and Italian air forces, the C-27J Spartan is on its way to defining
the new standard for medium tactical airlifters.
