MITSUBISHI AIRCRAFT CORPORATION

Patent Trials and Appeals Board

Sep 15, 2021

2021000894 (P.T.A.B. Sep. 15, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
15/456,782 03/13/2017 Yoichi Uefuji OBA-57269 1090
116 7590 09/15/2021
PEARNE & GORDON LLP
1801 EAST 9TH STREET
SUITE 1200
CLEVELAND, OH 44114-3108
EXAMINER
FILOSI, TERRI L
ART UNIT PAPER NUMBER
3644
NOTIFICATION DATE DELIVERY MODE
09/15/2021 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
patdocket@pearne.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
_______________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
_______________

Ex parte YOICHI UEFUJI, MASATOSHI MORISHITA,
TOSHIYUKI ISHIDA, and GENTO ICHIKAWA
_______________

Appeal 2021-000894
Application 15/456,782
Technology Center 3600
_______________

Before JEREMY J. CURCURI, JAMES W. DEJMEK, and
AMEE A. SHAH, Administrative Patent Judges.

DEJMEK, Administrative Patent Judge.

DECISION ON APPEAL
Appellant1 appeals under 35 U.S.C. § 134(a) from a Final Rejection of
claims 1–20. We have jurisdiction over the pending claims under 35 U.S.C.
§ 6(b).
We reverse.

1 Throughout this Decision, we use the word “Appellant” to refer to
“applicant” as defined in 37 C.F.R. § 1.42 (2019). Appellant identifies
Mitsubishi Aircraft Corporation as the real party in interest. Appeal Br. 2.
Appeal 2021-000894
Application 15/456,782

2
STATEMENT OF THE CASE
Introduction
Appellant’s disclosed and claimed invention generally relates to an
anti-icing system of an aircraft by using bleed air heat-exchanged with
outside air. Spec. 3, 5. In a disclosed embodiment, a determined flow of
outside air is used to cool bleed air to a desired temperature. Spec. 20.
Further, the air flow rate of the cooled bleed air is adjusted such that the
temperature of the anti-icing site (e.g., a wing of an aircraft) is at a desired
temperature. Spec. 20–21.
Figure 1 is illustrative and is reproduced below:

Figure 1 shows an embodiment of the claimed anti-icing system (1).
Spec. 13. As shown in Figure 1, a precooler (4) (i.e., heat exchanger) is
configured to accept (hot) bleed air from a bleed air source (3) and cooling
Appeal 2021-000894
Application 15/456,782

3
outside air. Spec. 16. The temperature of the cooled bleed air (i.e., output
from precooler (4)) is monitored by temperature sensor (9) and provided to
precooler control section (14), which adjusts the air volume (i.e., flow rate)
of the outside air to achieve a desired temperature of the cooled bleed air.
Spec. 16, 19–20. The cooled bleed air flows through structure (e.g., ducts
and valves) to anti-icing unit (2), which delivers the cooled bleed air to the
anti-icing site. Spec. 16, 18–19. Anti-icing control section (11) adjusts the
air flow rate (q) of the cooled bleed air based on myriad parameters
including the detected pressure of the cooled bleed air (as sensed by pressure
sensor (10)), the detected temperature of the anti-icing site (as sensed by
temperature sensor (16)), and air data (e.g., outside air temperature and
altitude). Spec. 20–21, Fig. 3. An additional consideration in adjusting the
air flow rate of the cooled bleed air is to maintain the structural integrity of
the air flow ducts. See Spec. 16–17, 22. That is, the temperature of the
structure (e.g., ducts) must be at or below a maximum temperature in order
to retain its mechanical strength. Spec. 19.
Claim 1 is illustrative of the subject matter on appeal and is
reproduced below with the disputed limitations emphasized in italics:
1. An anti-icing system of an aircraft, the anti-icing system
preventing icing on the aircraft with use of bleed air heat-
exchanged with outside air, the anti-icing system comprising:
a heat exchanger that is configured to exchange heat
between the bleed air and the outside air;
a supply destination that is configured to receive the bleed
air passed through the heat exchanger; and
a control section that is configured to adjust a flow rate of
the bleed air passed through the heat exchanger and subsequently
supplied to the supply destination, wherein the control section
includes a bleed air flow rate adjusting section that is configured
Appeal 2021-000894
Application 15/456,782

4
to adjust the flow rate of the bleed air passed through the heat
exchanger and subsequently supplied to the supply destination,
the bleed air flow rate adjusting section uses a first
relationship and a second relationship, the first relationship
being a relationship between an altitude and a pressure upper
limit that is an upper limit of pressure of the bleed air, the second
relationship being a relationship between outside air
temperature at which temperature of the bleed air reaches
allowable temperature of a member through which the bleed air
flows and a pressure upper limit that is an upper limit of pressure
of the bleed air, the second relationship being provided based on
the altitude,
when outside air temperature is lower than outside air
temperature at an intersection of the first relationship and the
second relationship, the bleed air flow rate adjusting section is
configured to adjust the flow rate of the bleed air while
suppressing the pressure of the bleed air to the pressure upper
limit or lower of the first relationship, and
when the outside air temperature is higher than the outside
air temperature at the intersection of the first relationship and the
second relationship, the bleed air flow rate adjusting section is
configured to adjust the flow rate of the bleed air while
suppressing the pressure of the bleed air to the pressure upper
limit or lower of the second relationship.

The Examiner’s Rejections
1. Claims 1–20 stand rejected under 35 U.S.C. § 112(b) as being
indefinite. Final Act. 3–5.
2. Claims 1–20 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Benson (US 4,671,318; June 9, 1987); Gatzke (US
2010/0288890 A1; Nov. 18, 2010); and Rannenberg (US 3,487,993; Jan. 6,
1970). Final Act. 6–28.

Appeal 2021-000894
Application 15/456,782

5
ANALYSIS2
Rejection under 35 U.S.C. § 112(b)
The Examiner finds three claim terms are indefinite under 35 U.S.C.
§ 112(b). See Final Act. 3–5. We address these terms seriatim.
a. “passed through”
Claim 1 recites, inter alia, a supply destination is configured to
receive “the bleed air passed through the heat exchanger;” a control section
configured to adjust a flow rate of “the bleed air passed through the heat
exchanger;” and a bleed air flow rate adjusting section configured to adjust
the flow rate of “the bleed air passed through the heat exchanger.”
The Examiner concludes the phrase “passed through” is vague and
indefinite because it is unclear whether “passed through” refers to bleed air
that goes into the heat exchanger or if it is bleed air that has already passed
through the heat exchanger. Final Act. 3. Moreover, the Examiner
concludes the “past tense recitation ‘passed through’ is the issue with the
claim.” Ans. 4.
Appellant explains the claim limitations relate to identifying the
particular air flow that is to have its air flow rate adjusted. Appeal Br. 6;
Reply Br. 2.
The test for definiteness under 35 U.S.C. § 112 (b) is whether “those
skilled in the art would understand what is claimed when the claim is read in
light of the specification.” Orthokinetics, Inc. v. Safety Travel Chairs, Inc.,

2 Throughout this Decision, we have considered the Appeal Brief, filed
June 12, 2020 (“Appeal Br.”); the Reply Brief, filed November 17, 2020
(“Reply Br.”); the Examiner’s Answer, mailed September 17, 2020 (“Ans.”);
and the Final Office Action, mailed January 27, 2020 (“Final Act.”), from
which this Appeal is taken.
Appeal 2021-000894
Application 15/456,782

6
806 F.2d 1565, 1576 (Fed. Cir. 1986). “A claim is not ‘indefinite’ simply
because it is hard to understand when viewed without benefit of the
specification.” S3 Inc. v. NVIDIA Corp., 259 F.3d 1364, 1369 (Fed. Cir.
2001). Further, that a claim is broad does not mean that it is indefinite. See
In re Johnson, 558 F.2d 1008, 1016 n.17 (CCPA 1977); In re Miller, 441
F.2d 689, 693 (CCPA 1971); In re Gardner, 427 F.2d 786, 788 (CCPA
1970). During prosecution, “‘[a] claim is indefinite when it contains words
or phrases whose meaning is unclear.’” Ex parte McAward, Appeal 2015-
006416, 2017 WL 3669566, at *5 (PTAB Aug. 25, 2017) (precedential)
(quoting Packard, 751 F.3d at 1310, 1314); see In re Packard, 751 F.3d
1307, 1313 (Fed. Cir. 2014) (“claims are required to be cast in clear—as
opposed to ambiguous, vague, indefinite—terms”) (per curiam).
Informed by, and consistent with the Specification, we agree with
Appellant that when read in context of the claim, the limitations identify the
particular air flow that is being adjusted or received. In particular, it is the
cooled bleed air—the air that has already passed through the heat
exchanger—that has its air flow rate adjusted and is presented to anti-icing
unit (2) by supply line (6). See Spec., Fig. 1.
Accordingly, we disagree with the Examiner that the term “passed
through” is vague and indefinite under 35 U.S.C. § 112(b).

b. “allowable temperature”
Claim 1 recites the bleed air flow rate adjusting section uses a first
relationship and a second relationship, wherein the second relationship is a
relationship between the outside air temperature “at which [the] temperature
Appeal 2021-000894
Application 15/456,782

7
of the bleed air reaches [an] allowable temperature of a member though
which the bleed air flows” and an upper limit of pressure of the bleed air.
The Examiner concludes that an “allowable temperature” is a relative
term that renders the claim indefinite. Final Act. 3. The Examiner explains
that the Specification does not define what an allowable temperature is and,
therefore, the term is vague and indefinite. Final Act. 3–4; Ans. 4–5. For
examination purposes, the Examiner interprets an allowable temperature as
“any temperature that a member reaches through which the bleed air flows.”
Final Act. 4.
Appellant asserts that the Specification “expressly identifies the
allowable temperature as a temperature at which ‘the bleed air lines reliably
retain the mechanical strength.’” Appeal Br. 7 (citing Spec. 19); Reply
Br. 2–3. Appellant further asserts that one of ordinary skill in the art would
be able to “determine temperatures at which the bleed air lines retain their
mechanical strength.” Reply Br. 3.
When construing claim terminology during prosecution before the
Office, claims are to be given their broadest reasonable interpretation
consistent with the Specification, reading claim language in light of the
Specification as it would be interpreted by one of ordinary skill in the art.
In re Am. Acad. of Sci. Tech Ctr., 367 F.3d 1359, 1364 (Fed. Cir. 2004).
However, the broadest reasonable interpretation differs from the broadest
possible interpretation. In re Smith Int’l, Inc., 871 F.3d 1375, 1383 (Fed.
Cir. 2017). The correct inquiry in giving a claim term its broadest
reasonable interpretation in light of the specification is “an interpretation
that corresponds with what and how the inventor describes his invention in
the specification, i.e., an interpretation that is ‘consistent with the
Appeal 2021-000894
Application 15/456,782

8
specification.’” Smith, 871 F.3d at 1382–83 (quoting In re Morris, 127 F.3d
1048, 1054 (Fed. Cir. 1997)). Additionally, we are mindful that limitations
are not to be read into the claims from the Specification. In re Van Geuns,
988 F.2d 1181, 1184 (Fed. Cir. 1993).
As an initial matter, we disagree with the Examiner’s construction
(see Final Act. 4), that an allowable temperature is “any temperature that a
member reaches through which the bleed air flows.” We note that
independent claim 3 recites setting a temperature threshold “lower by a
predetermined value than [the] allowable temperature of a member through
which the bleed air flows.” Thus, rather than a range (or “any
temperature”), an allowable temperature refers to a particular temperature.
Moreover, as discussed in the Specification, the structure components (e.g.,
ducts and valves) are designed to maintain their mechanical strength at an
“allowable temperature AT or lower.” Spec. 17; see also Spec. 19 (“The
members configuring the bleed air lines reliably retain the mechanical
strength at the respective allowable temperature AT or lower.”).
Consistent with the Specification, we construe an allowable
temperature to be the maximum temperature at which the bleed air lines
reliably retain their mechanical integrity. Although the Specification does
not expressly specify the temperature value, an ordinarily skilled artisan
would be able to determine a maximum temperature for bleed air lines based
on the material used and the particular configuration used.
Accordingly, we disagree with the Examiner that the term “allowable
temperature” is vague and indefinite under 35 U.S.C. § 112(b).

Appeal 2021-000894
Application 15/456,782

9
c. “a range of an altitude and outside air temperature”
Claim 4 recites, inter alia, “an icing condition and an operating
condition are assumed, the icing condition including an altitude and outside
air temperature, and the operating condition encompassing the icing
condition and being a range of an altitude and outside air temperature at
which the aircraft is flyable.”
The Examiner concludes that the phrase “a range of an altitude and
outside air temperature” is a relative term and renders the claim indefinite.
Final Act. 4; see also Ans. 5–6. Moreover, the Examiner determines the
claim does not provide additional information defining the boundaries of the
recited range. Ans. 5.
As set forth in the Specification, the anti-icing system is intended to
function in an icing condition as well as in an operating condition “for
performance improvement.” Spec. 18. Figure 2 is illustrative and is
reproduced below.

Appeal 2021-000894
Application 15/456,782

10
Figure 2 illustrates the icing and operating conditions (C1 and C2,
respectively) of an aircraft defined by two ranges of altitude and outside air
temperature. Spec. 13, 18. As shown, the range of altitude and outside air
temperature of operating condition (C2) encompasses icing condition (C1).
Further, in context of the claim limitation, the operating condition is the
range of outside air temperatures and altitude “at which the aircraft is
flyable.” See claim 4. Although the range of outside air temperatures and
altitudes at which an aircraft is flyable is broad, it is not indefinite. See
Gardner, 427 F.2d at 788 (“Breadth is not indefiniteness.”).
Accordingly, we disagree with the Examiner that the phrase “a range
of an altitude and outside air temperature” is relative and indefinite under
35 U.S.C. § 112(b).

We, therefore, do not sustain the Examiner’s rejection of claims 1–20
under 35 U.S.C. 112(b) as indefinite.

Rejection under 35 U.S.C. § 103
The Examiner rejects claim 1, inter alia, under 35 U.S.C. § 103 over
the combined teachings of Benson, Gatzke, and Rannenberg. Final
Act. 6–11. We begin our analysis with a brief review of Benson and Gatzke.
Benson generally relates to an aircraft engine bleed air flow balancing
technique. See Benson, Title. More particularly, Benson describes “a
system for controlling bleed air supplied by the engines of a multi-engine
aircraft in order to ensure a balanced supply of bleed air from each of the
engines on the aircraft, thereby achieving balanced flow extraction.”
Benson, col. 1, ll. 11–15. Benson discloses that for reasons of fuel economy
Appeal 2021-000894
Application 15/456,782

11
and unbalanced engine wear, it is desirable to use bleed air supplied from all
of the engines on a multi-engine aircraft rather than using bleed air from a
single source. Benson, col. 1, ll. 26–35. Benson discloses it is known to use
pressure regulating valves to control the amount of bleed air supplied from
each engine. Benson, col. 1, ll. 35–41. Benson further teaches that the
pressure regulating valves are susceptible to mechanical tolerances that
affect their performance tolerance. Benson, col. 1, ll. 58–65. To address the
performance tolerance of the pressure regulating valves, Benson’s invention
uses a bleed flow modulator in conjunction with each pressure regulating
valve. Benson, col. 3, ll. 8–12, col. 4, ll. 39–42.
Figure 1 of Benson is illustrative and is reproduced below.

Figure 1 of Benson is a flow diagram of Benson’s disclosed system
illustrating the incorporation of the bleed flow modulator. Benson, col. 3,
ll. 55–58. As shown, bleed air is sourced from engine 1 (10) and is passed to
Appeal 2021-000894
Application 15/456,782

12
pressure regulating valve (12). Benson, col. 4, ll. 15–16. Pressure
regulating valve (12) regulates the pressure of the bleed air presented to heat
exchanger (14). Benson, col. 4, ll. 15–18. Bleed flow modulator (24)
operates as a function of upstream pressure (i.e., the pressure of the bleed air
supplied to heat exchanger (14)) and downstream pressure (i.e., the pressure
of the cooled bleed air exiting heat exchanger (14)). Benson, col. 4,
ll. 59–63, col. 5, ll. 18–22. Bleed air modulator (24) provides a feedback
signal to pressure regulating valve (12) to balance the flow of bleed air that
is supplied by heat exchanger (14) to ECS (environmental control system)
manifold (16). Benson, col. 4, ll. 62–66.
More particularly, Benson describes it is known that the pressure drop
across heat exchanger (14) is mathematically related to the flow of the bleed
air through heat exchanger (14). Benson, col. 5, 3–8. Thus, by regulating
the pressure drop across the various heat exchangers in the multi-engine
aircraft, the flow of the bleed air from the heat exchangers will be balanced.
Benson, col. 5, ll. 8–16.
Gatzke generally relates to an engine bleed air duct arrangement on
the wing of an aircraft. Gatzke ¶ 1. Gatzke describes it is known to use
engine bleed air for myriad systems in an aircraft, including anti-icing
applications. Gatzke ¶¶ 2–4; see also Gatzke ¶ 63 (describing “the engine
bleed-air can be used for de-icing structural components of the aircraft, and
in particular the wing”). Gatzke further discloses it is known to use a heat
exchanger and ambient air to cool engine bleed air and that the cooled bleed
air may be conveyed to a region to counteract icing that occurs in the region.
Gatzke ¶ 4.
Appeal 2021-000894
Application 15/456,782

13
Gatzke describes an embodiment of a wing-engine structure
comprising an engine bleed air duct extending along the wingspan direction
and an ambient air duct extending along the engine bleed air duct arranged
so that the engine bleed air duct and the ambient air duct “form[] a heat
exchanger deice for cooling the air flowing in the engine bleed-air duct.”
Gatzke ¶¶ 8–10, 63, 71. Additionally, Gatzke describes integrating a device
in the ambient air duct to influence the flow in the ambient air duct. Gatzke
¶¶ 16, 66. Exemplary devices may be an aperture changing device or a flow
assist drive. Gatzke ¶ 88. Gatzke further describes an additional control
device that comprises a function based on flight state data acquired by a
sensor device. Gatzke ¶¶ 18–22. The control device generates control
signals which are sent to the device for influencing the flow in the ambient
air duct. Gatzke ¶¶ 18–22, 88–89. Gatzke describes the sensor device may
acquire flight state data such as the outside temperature, aircraft speed, flight
altitude, and absolute pressure, which are then sent to the control device
where they are used by the control function to generate control signals.
Gatzke ¶¶ 22, 24, 90, 94.
Gatzke also describes an embodiment in which a regulating device
may be used to regulate the quantity of bleed air flowing into the bleed air
duct. Gatzke ¶ 51. For example, Gatzke describes the quantity of inflowing
bleed air may be a function of desired air temperature in the bleed air duct.
Gatzke ¶ 51. That is, if the air temperature in the bleed air duct is lower than
a desired temperature, more bleed air may be allowed into the bleed air duct.
Gatzke ¶ 51. Conversely, if the temperature of the air in the bleed air duct is
higher than a desired temperature, the regulating device may restrict the
inflow of bleed air. Gatzke ¶ 51. Gatzke further describes that the
Appeal 2021-000894
Application 15/456,782

14
“regulating device can also be functionally coupled to at least one further
aircraft system function, which transmits a temperature value to the
regulating device, for example the ambient temperature of the aircraft.”
Gatzke ¶ 51.
Appellant asserts the prior art fails to teach a bleed air flow rate
adjusting section that adjusts the flow rate of the cooled bleed air (i.e., bleed
air passed through the heat exchanger) based on a first relationship between
an altitude and an upper limit of pressure of the bleed air, and a second
relationship, based on altitude, between the outside air temperature at which
the temperature of the bleed air reaches an allowable temperature and an
upper limit of pressure of the bleed air. Appeal Br. 8–10; Reply Br. 4–5. In
particular, Appellant argues that Benson regulates air flow to an equilibrium
point by monitoring upstream and downstream pressures, but is silent as to
the claimed relationships. Appeal Br. 9; Reply Br. 4–5. Additionally,
Appellant argues Gatzke is limited to adjusting the flow in an ambient air
duct (rather than bleed air, as claimed) and also fails to teach the claimed
second relationship. Appeal Br. 9. Moreover, Appellant asserts that “any
application of the cited teachings in Gatzke would only be applied to the
control of ambient air, not bleed air.” Appeal Br. 9–10; Reply Br. 4–5.
In response, the Examiner explains that Benson was not relied on to
teach the claimed relationships (i.e., between altitude and an upper limit of
pressure or between an outside air temperature and the upper limit of
pressure). Ans. 7. Instead, the Examiner explains that Gatzke was relied on
to teach the claimed relationships. Ans. 7 (citing Final Act. 7–8).
Moreover, the Examiner states:
Appeal 2021-000894
Application 15/456,782

15
it is known in aviation that bleed air flow adjusting suggests
using certain parameters and relationships, such as between fresh
air which has been picked from atmosphere, and pressurized air,
and high temperatures, and what is done with the air to control
environmental conditions inside the aircraft relating to flying
altitude and the outside temperatures. It is also know[n] in
aviation that altitude refers to the height of an aircraft above sea
level.
Ans. 8. Notwithstanding the prior statement regarding not relying on
Benson to teach the claimed relationships, the Examiner states “Benson
suggests these relationships.” Ans. 8. More specifically, the Examiner
explains that for Benson’s system to operate as disclosed, the aircraft would
need to be turned on and likely be in-flight. Ans. 8.
Although the Examiner explains it is known in aviation that there are
relationships between certain parameters, such as fresh air and pressurized
air, the Examiner still has not set forth sufficient persuasive evidence or
technical reasoning that Benson or Gatzke, alone or in combination, teaches
or suggests the claimed relationships—i.e., a first relationship between
altitude and a pressure upper limit, and a second relationship between
outside air temperature at which the temperature of the bleed air reaches the
claimed allowable temperature of a member through which the bleed air
flows and a pressure upper limit of the bleed air. Nor does the Examiner’s
statement in the Answer rise to the level of taking Official Notice of such
relationships. Further, for us to sustain the Examiner’s rejection, we would
need to resort to impermissible speculation or unfounded assumptions or
rationales to cure the deficiencies in the factual bases of the rejection before
us. In re Warner, 379 F.2d 1011, 1017 (CCPA 1967).
Because we find it dispositive that the Examiner has not shown by a
preponderance of evidence that Benson or Gatzke teaches or reasonably
Appeal 2021-000894
Application 15/456,782

16
suggests either of the claimed relationships, we do not address other issues
raised by Appellant’s arguments related to claim 26. See Beloit Corp. v.
Valmet Oy, 742 F.2d 1421, 1423 (Fed. Cir. 1984) (finding an administrative
agency is at liberty to reach a decision based on “a single dispositive issue”).
For the reasons discussed supra, on the record before us, we do not
sustain the Examiner’s rejection of independent claim 1. For similar
reasons, we do not sustain the Examiner’s rejection of independent claims 3,
and 8–11, which recite at least the claimed first relationship. In addition, we
do not sustain the Examiner’s rejections of claims 2, 4–7, and 12–20, which
depend directly or indirectly therefrom.

CONCLUSION
We reverse the Examiner’s decision rejecting claims 1–20 under
35 U.S.C. § 112(b).
We reverse the Examiner’s decision rejecting claims 1–20 under
35 U.S.C. § 103.

DECISION SUMMARY
Claim(s)
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–20 112(b) Indefiniteness 1–20
1–20 103 Benson, Gatzke,
Rannenberg
1–20
Overall
Outcome
1–20

REVERSED