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(R-R) Trent XWB-97 engines, is the largest A350, with capacity
for up to 366 passengers in three-class configuration (created by
the addition of 11 fuselage frames) and a slightly reduced 7,950-
nm range suitable for, say, Shanghai-Boston or Dubai-Melbourne
Differences from the current A350-900 include introduction of
six-wheel landing-gear bogies (to reduce airport-pavement loading
by spreading its higher gross weight) and an enhanced wing with
extended trailing edges that reduce approach speed for landing,
says Airbus senior marketing vice president François Caudron.
Such changes are enough to require a separate flight-test pro-
gramme, according to Cail, who claims that the A350-900’s “high
level of maturity” nevertheless permitted Airbus to keep the cam-
paign to “less than one year with [ just] three prototypes”.
Meanwhile, in the Airbus factories across Europe, production is
gearing up as the manufacturer prepares to build 10 A350s a month
by the end of next year. For example, the British plant — which pro-
duces wings in north Wales — had by the start of the year delivered
units for at least five Series 1000 airframes (among the 72 ship-sets of
A350 wings shipped during 2016) and had begun work for MSN144.
Introduction of the final A350-1000 flight-test aircraft does
not mean that ground testing has been completed, however. In
February, Airbus reported that an optimised means of ground
vibration testing new aircraft had reduced “this validation phase
for the stretched-fuselage A350-1000” and would be used for the
Such testing measures aircraft dynamic behaviour, confirming
theoretical models of various flight conditions “such as manoeuvring,
flying in gusty conditions and during landing”. Collected data con-
tributes to clearance of an aircraft’s flight envelope, part of the certi-
fication process. A350-1000 ground vibration testing was performed
over two days, compared with the nine-day period required for the
A350-900 (and more than a month for previous Airbus models).
The 1,600FH of testing are being shared among the three A350-
1000s, although Airbus does say how much time has been budgeted
against each phase of the programme. Lead aircraft MSN059 is
scheduled to perform 600FH, with the balance divided equally be-
tween MSNs 065 and 071. (The latter made its first flight on January
10 this year, less than seven weeks after that of MSN059.)
Airbus has detailed the “heavy” FTI on MSN059, which has been
involved in exploration of the flight envelope, handling qualities,
loads, and braking. The test equipment provides the FITC with over
600,000 parameters of flight-test data.
More than 200 different sorts of sensors capture 2,850 analogue
and 150 discrete measurements, while information can be trans-
mitted to the ground at the rate of 100Mbits/sec. Cail says that the
120,000km of cabling throughout the aircraft represents “about half
that used for previous aircraft”.
Three flight-test engineer (FTE) stations are used to monitor
aircraft data, while two powerplant specialists gather engine infor-
mation. Beyond provision for personnel immediately required on
each test flight, Airbus also can install a 51-seat “flight test cabin”
on MSN059 for specialist ground-support staff and mechanics when
the aircraft operates away from its French base.
Using up to 15 internal and external video cameras, each FTE
station can reproduce the situation on the flight-deck and provide
external views of the engines, trailing-edge flaps and leading-edge
slats, and the landing-gear. Dedicated configurable screens are used
for real-time monitoring of eight cockpit displays and can capture
“many parameters that the pilots cannot see and access”, says Cail.
Three engineers at the main FTE station manage and monitor all
test parameters, with Cail at pains to emphasise that the flight-test air-
craft “is not configured by the pilot but by the engineer ”. Accordingly, it
is “very important” that the FTE feels as though they are in the cockpit.
A routine but vital element of the work involves repeated flying
exercises at different centres of gravity (cg). To obviate the need for
separate flights for each position, MSN059 carries 10 tonnes of water/
glycol liquid ballast, which can be transferred between forward and
aft tanks in just four minutes to adjust the location of the aircraft cg.
MSN071, the second heavily equipped A350-1000, is being flown
to evaluate autopilot, braking, engine, and systems performance
(complementing MSN059’s powerplant and systems work) and to
perform environmental tests. It has identical FTE stations to those
in the lead aircraft, but its FTI architecture is a subset of MSN059’s
equipment. Additionally, each aircraft has dedicated instrumentation
linked to its specific flight-test role.
For real-time systems analysis and monitoring, flight-test param-
eters are transmitted from the test aircraft to a ground telemetry
room employing over 100 specialist engineers. When MSN059 made
the first A350-1000 flight last December, Airbus used two telemetry
rooms in Toulouse, and three more at Airbus sites at Bremen and
Hamburg in Germany and in Bristol in the UK.
FITC engineers are able to supplement test observations from
the aircraft with those obtained by an accompanying Dassault Fal-
con 20 executive “chase ‘plane”. Falcon crew members include an
Airbus flight-test pilot who can monitor and (if necessary) assist a
flight-test aircraft. Escorting the flight-test aircraft, they can provide
an external view.
Airbus has established the term “Airline1” for its in-house replica
of in-service operation. It is repeating an earlier A350-900 exercise
in simulating airline “experience” to focus on aircraft maturity and
operability. Dedicated “Airline1” staff coordinates flights by the three
A350-1000s with the Toulouse FITC, managing a hangar and provid-
ing daily maintenance, support, and aircraft repairs in an operating
environment intended to replicate commercial service.
“ We’re reinforcing Airline1 to improve the way we manage poten-
tial failures and increase our understanding not just of the aircraft,
but of our customers’ world,” according to Philippe Garnier, head of
A350 maturity and operability. “ This is about improving maintenance
efficiency, developing effective health-monitoring, and delivering
machines that have the highest-possible levels of maturity to our
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