731 Falcon 20B

Operations
731
FALCON 20B
T
he Dassault Falcon 20 aircraft,
arguably the matriarch of the mid-size
class, seems to age as well as vintage
Bordeaux wine. It offers one of the
largest cabins in its class. It has airliner-like
systems, such as fully-powered
hydraulic control actuators, leading
edge slats and glass windshields. It’s
light on the controls, it’s easy to fly,
and it’s hard to make a bad landing
because of its long-travel, trailing-link
landing gear.
The availability of the first
AlliedSignal TFE731 turbofan engine
retrofit in the late 1980s assures that
the Falcon 20 will be in service well
into the next century. Replacing the
original GE CF700 engines with 4,500-
pound-thrust TFE731-5AR turbofans
boosts the range by as much as 65 percent.
The 731 Falcon 20 also is a good
neighbor because of its greatly reduced
airport noise signature.
The downside of the -5AR retrofit is
longer takeoff field lengths, especially
during hot-and-high departures. In
addition, the -5AR conversion increases
the BOW by 250 pounds, and the
MTOW has been bumped up by 500
pounds to 29,100 pounds. The added
takeoff weight further lengthens the
required runway compared to the original
aircraft.
In 1991, AlliedSignal and Dassault
certificated the 731 Falcon 20B, which
is a second-generation engine retrofit
program. TFE731-5BR engines, rated
at 4,750 pounds of thrust for takeoff,
replace the -5AR engines of the firstgeneration
731 Falcon 20. Compared
to the -5AR engines, the -5BR turbofans
have a high pressure ratio, more
thrust and more flat-rating for takeoff,
seven percent more climb and cruise
thrust, and two percent better specific
fuel consumption. Upgrading from
-5AR to -5BR engines only adds 25
pounds to the BOW, and the MTOW
remains unchanged at 29,100 pounds.
The additional thrust enables the
731 Falcon 20B to climb directly to FL
410. That’s 2,000 feet higher than the
731 Falcon 20’s initial cruise altitude
This aircraft’s -5B engines greatly
improve takeoff performance, especially
when departing hot-and-high airports.
143 lb/
Second Total
Inlet Air (Core and Bypass)
LP Compression Core Engine Exhaust Combustion
HP Compression Mixed Exhaust Bypass Exhaust
and 4,000 feet higher than an unmodified
Falcon 20. Under standard day
conditions, the 731 Falcon 20B’s extra
thrust and better specific range result
in two to three percent more range
and slightly faster block times compared
to the -5AR version.
But, when departing from hot-andhigh
airports, the -5BR engines give
the 731 Falcon 20B a marked increase
in performance. For example, at 5,000
feet, ISA+20°C, the -5BR-equipped
aircraft can depart at 28,600 pounds,
thereby endowing it with as much as
500 nm more range than the -5AR version.
Even more impressively, the 731
Falcon 20B’s roughly 2,000-nm range
under such constraints is almost double
that of a stock Falcon 20.
It should be noted, however, that the
731 Falcon 20B must make a flaps-up
takeoff when departing under such
hot-and-high conditions. That results
in a takeoff field length of 11,805 feet.
We flew AlliedSignal’s 731 Falcon
20B demonstrator on a short mission
AlliedSignal TFE731-5BR
Core Engine
Bypass Duct
111 lb/Second
32 lb/
Second
to sample its improved climb and
cruise performance. Departing San
Diego Lindbergh Field at 28,500
pounds, our takeoff field length was
5,000 feet according to the approved
flight manual. After takeoff, we were
cleared for an unrestricted climb to
FL 370. Dassault’s performance manual
predicted a time to climb of 23
minutes. Our actual climb time was 30
minutes.
After level off, the aircraft accelerated
to 0.78 IMN, resulting in a true airspeed
of 455 knots. Our fuel flow was
1,700 pph. The book predicted 458
knots with a fuel flow of 1,670 pph.
Some of the variation between actual
and book performance can be
explained by the demonstrator’s being
equipped with thrust reversers.
The book performance numbers are
based on non-thrust reverser exhaust
nozzles.
The current asking price for a mid-
1970s vintage Dassault Falcon 20F is
$1.8 million to $2.65 million, depend-
Source: AlliedSignal/Rendered by Wendy Tittel
FROM FEBRUARY 1997 BUSINESS & COMMERCIAL AVIATION.
© 1997, THE McGRAW-HILL COMPANIES, INC. ALL RIGHTS RESERVED.

The additional
thrust enables
the 731 Falcon
20B to climb
directly to FL 410.
that’s comparable to the Hawker
800XP.
The average new, mid-size aircraft
costs more than $10 million. The cost
of a 731 Falcon 20B ranges between
$5.5 million and $8 million, depending
upon base price of the unmodified airplane,
plus options and cosmetic refurbishment.
Those numbers suggest
that the 731 Falcon 20B will be well
represented in the business aircraft
fleet for several years to come.
By Fred George
ing upon age and condition. AlliedSignal’s
price for the 731 Falcon 20B conversion
is $3.6 million, according to
Don Sterling, manager of marketing
and sales of the 731 Falcon 20B
Retrofit Program. (If you already operate
a 731 Falcon 20 with -5AR engines,
upgrading to the 731 Falcon 20B conversion
costs $150,000 to $160,000 if
the aircraft is enrolled in AlliedSignal’s
Maintenance Service Plan.) Add
in another $327,600 and 250 pounds if
you want thrust reversers.
A new digital avionics suite by
AlliedSignal or Rockwell-Collins,
including five-tube EFIS, runs about
$1.3 million. Sterling claims that Garrett
Aviation, with Dassault Falcon
Jet’s assistance, plans to obtain RVSM
certification by the middle of this year.
The current asking price for a fully
completed 731 Falcon 20B on the used
market is $5.2 million, but there are
very few on the market. It appears
that 731 Falcon 20Bs are returning 80
percent or more of the initial investment
on resale.
This may be explained by its performance
in comparison to other, more
contemporary mid-size aircraft. When
needed, it can dash at 0.82 IMN at
maximum cruise power. At a longrange
cruise speed of 424 knots, it can
carry eight passengers 2,258 nm with
NBAA IFR reserves. Its specific range
at 440 knots is 0.310 nm/lb, which is
competitive with the latest business
aircraft offering comparably sized cabins.
Its operating costs are reasonably
close to those of other aircraft in its
class. Such performance numbers may
explain why 90 Falcon 20 aircraft have
been retrofitted with TFE731 engines.
In comparison to current-production
mid-size aircraft, the 731 Falcon 20B
has virtually the same range as a Learjet
60, a cabin with essentially the
same volume as a Hawker 1000 and
standard-day runway performance
FROM FEBRUARY 1997 BUSINESS & COMMERCIAL AVIATION.
© 1997, THE McGRAW-HILL COMPANIES, INC. ALL RIGHTS RESERVED.