Download passenger load factor with the current, lower take-off

passenger load factor with the current,
lower take-off weight version of the...kit. At
a load factor of 70%, this number increases
to approximately 98%."
Tony Smith, director airline marketing at
R-R's US subsidiary, says that the manufacturer is benefiting today from a more
sophisticated analysis of the hushkit-versusre-engine argument. He explains: "I think
the industry has got beyond the stage of
trying to compare the $3 million and $10
million numbers and that is mainly because
we have been going around banging on
their doors".
His tactic is to move away from the
capital-cost comparison and into the area of
operating costs where, he argues, R-R steadily claws back the capital spent through
savings on fuel and maintenance, additional
payload, higher utilisation and tax and
residual value advantages. UPS, for example, factored in the savings from deferral of
new aircraft purchases.
CRITICAL ISSUE
Hushkilling, he argues, although initially
cheaper, adds costs steadily in the form of
additional fuel burn and payload loss.
Clearly the likely operating life of an
aircraft is critical to the argument. This is
why the noise issue is inextricably linked to
the ageing-aircraft question. The point was
crystallised by UPS which assumed a 20year remaining life for its aircraft, achievable because of their lower cycles compared
with passenger aircraft, and which made its
re-engining decision easier.
Smith says: "For those aircraft that can be
hushkitted with minimum trade or de-rate,
the cyclic life remaining precludes a 12-year
operation to repay the [hushkit] investment. Conversely, those aircraft with the
longest productive life remaining are the
high gross weight, hushkit-limited aircraft."
Compared with the 727 situation, the 737
market is simpler. Only R-R and the P&W/
Nordam team are serious players, and only
the 737-200 is a candidate for treatment.
R-R estimates that of about 765 -200s in
service in the noise-restricted countries, 696
have the life required to be Tay 670
re-engining possibilities. The small numbers
of ageing -100s can be hushkitted or
re-engined but most will be retired. Carriers
with well-positioned re-equipment orders,
notably American Airlines, are also planning to offload their -200s.
The Nordam kit includes respaced inlet
guide vanes, internal mixer, acoustic treatment and fixed ejector suppressor at a cost
of some $3 million. Certification is not due
until the end of 1991 but Nordam claims to
have demonstrated Stage III compliance in
proof-of-concept flight tests for aircraft with
JT8D-7, -9, -15 and -17 engines. It claims
82 shipset orders and 82 options.
Nordam's task has not been simple and
has resulted in a relatively complex kit
which increases fuel burn by up to 6% and,
22
at heavier weights, requires "trade-offs" to
achieve Stage 3. Although it meets the
requirements cumulatively, it is actually
above the limit in the
take-off cutback condition but trades that
against its comfortable margin on approach and slight
margin in sideline
noise.
Nordam also had to
modify the aircraft
flaps to allow full deployment with the extended nacelle in
place, although the
final aerodynamic effect is claimed to be
negligible. It now
plans an aerodynamic
improvement package
for the 737, which
would recover the
fuel-burn penalty.
Top: P&W/Nordam's kit for the 737 requires a flap modification.
P&W says the kit Below: P&W's suppressor is crucial to its JT8 quietening effort
will reach Stage III at
weights in excess of 55,400kg with full flap, engines is also certificated and is in service
but Lufthansa requires only 52,200kg, with ABX, but it requires a more complex
which can be achieved without trade-offs. kit with acoustic treatment, respaced inlet
R-R questions publicly whether Nordam guide vanes and an internal mixer. The cost
will achieve the higher figure and suggests approaches $1.9 million.
that 425 aircraft will not reach Stage 3 at
The DC-9 market has been the most
gross weight with hushkits.
sluggish so far and there is a question as to
The third aircraft which P&W has to how many kits ABS will be able to sell
address is the DC-9. In that task, it joins the outside ABX. The small DC-9-10 aircraft are
ABS consortium, which includes Airborne old and undesirable, and the larger -40 and
Express, whose airline subsidiary ABX Air -50 are good re-engining candidates. R-R
is first customer. ABS has an STC for its estimates that 146 of the -40/-50 variants
JT8D-7-powered DC-9-10 kit for weights up are Tay possibilities, noting that Douglas
to the 41,178kg maximum. The kit has an has said that properly maintained DC-9s
internal mixer and modified thrust reverser, can be operated to 100,000 cycles.
and costs as little as $1.2 million.
P&W has another card to play against the
The heavier DC-9-30 with -7, -9, and -11 Tay. Although R-Rs engine is well ahead of
FLIGHT INTERNATIONAL U - 20 August, 1991