United States Court of Appeals 

for the Federal Circuit ______________________

HONEYWELL INTERNATIONAL INC.,

Appellant

v.

ARKEMA INC., ARKEMA FRANCE,

Appellees

______________________

2018-1151, 2018-1153

______________________

Appeals from the United States Patent and Trademark 

Office, Patent Trial and Appeal Board in Nos. PGR2016-

00011, PGR2016-00012.

______________________

Decided: October 1, 2019

______________________

JOHN C. O'QUINN, Kirkland & Ellis LLP, Washington, 

DC, argued for appellant. Also represented by GREGG 

LOCASCIO, WILLIAM H. BURGESS, NOAH SAMUEL FRANK,

CALVIN ALEXANDER SHANK. 

 MARK J. FELDSTEIN, Finnegan, Washington, DC, argued for appellees. Also represented by ERIN SOMMERS,

MARK D. SWEET. 

 ______________________

Before NEWMAN, REYNA, and HUGHES, Circuit Judges.
2 HONEYWELL INTERNATIONAL INC. v. ARKEMA INC.

REYNA, Circuit Judge.

Honeywell appeals from a pair of post-grant review 

proceedings involving a single Honeywell patent. Following institution, Honeywell sought authorization from the 

Board to file a motion for leave to petition the Patent and 

Trademark Office Director for a Certificate of Correction to 

correct the challenged patent. Honeywell sought to correct 

a mistake in the chain of priority listed on the face of the 

patent. The Board rejected Honeywell’s request. Because 

we conclude that the Board abused its discretion in rejecting Honeywell’s request for authorization to file a motion 

for leave, we vacate and remand.

BACKGROUND 

I. The ’017 Patent

Honeywell International Inc. (“Honeywell”) owns U.S. 

Patent No. 9,157,017 (“the ’017 patent”), which is directed 

to fluoroalkene compounds used in refrigeration systems 

and other applications. The ’017 patent issued on October 

13, 2015, and recites a chain of priority applications dating 

back to 2002, all of which were incorporated by reference

into the ’017 patent.

During prosecution of the ’017 patent, Honeywell filed 

a preliminary amendment that cancelled all 20 claims recited in the original application and added 20 new claims 

directed to admittedly different subject matter: automobile 

air conditioning systems. In the proceedings below, Honeywell asserted for the first time that when it made the 

preliminary amendment, it inadvertently failed to make 

corresponding amendments to the list of priority applications. J.A. 156:10–13 (asserting an “inadvertent error in 

failing to make a claim of priority to [certain] sister chains 

of cases that we could have made at that time”). As a result, when the ’017 patent issued, the list of priority applications listed on the face of the patent was materially the 

same as the initial application. 
HONEYWELL INTERNATIONAL INC. v. ARKEMA INC. 3

II. Arkema’s 

PGR2016-00012 and PGR2016-00011

Four months after the ’017 patent issued, Arkema Inc. 

(“Arkema”) filed two petitions for post-grant review 

(“PGR”) of the ’017 patent with the Patent Trial and Appeal 

Board (“Board”) of the Patent and Trademark Office 

(“PTO”). Both petitions asserted that the priority applications listed on the face of the ’017 patent did not provide 

written description support for the issued claims. As a result, Arkema argued, the claims of the ’017 patent were 

only entitled to a priority date of March 26, 2014—the filing date of the application that led to the ’017 patent—rather than the 2002 priority date that would result if the 

priority chain adequately supported the claims. 

Based on that contention, Arkema argued that the ’017 

patent was eligible for PGR proceedings, which are available only for patents having at least one claim with an effective filing date on or after March 16, 2013. Arkema also 

presented several prior art references, including work by 

Honeywell’s own inventors, dated from the period between 

2002 and 2014. 

According to Honeywell, it did not immediately realize 

that the alleged lack of written description support 

stemmed from a mistake in the priority chain. Instead, in

its Preliminary Patent Owner Response to Arkema’s petition, Honeywell argued that all claims of the ’017 patent 

were entitled to a priority date at least as early as 2004

based on the priority chain listed on the patent. As a result, Honeywell claimed, the ’017 patent was not eligible 

for PGR proceedings. The Board rejected Honeywell’s argument and instituted both post-grant review proceedings.

Honeywell asserts that it realized the priority chain 

mistake when preparing its Patent Owner Response. Honeywell then requested permission to file a motion for leave 

to request a Certificate of Correction from the Director of 

the PTO (“Director”) that would amend the priority chain 
4 HONEYWELL INTERNATIONAL INC. v. ARKEMA INC.

of the ’017 patent. Honeywell explained that its proposed 

correction would include additional Honeywell patent applications in the priority chain that disclosed automotive 

air conditioning subject matter, and thus conferred a different priority benefit. 

The Board held two telephonic conferences to discuss

Honeywell’s request. In response to questions from the 

Board, Honeywell conceded that the mistake was not a 

clerical or typographical error, but it argued that a Certificate of Correction is a permissible means for making “a 

change in the priority chain.” J.A. 155:19–22. Honeywell 

also argued that this change was “minor” because it did not 

change the substance of the claims or the specification. 

J.A. 155:13–25. Finally, in response to the Board’s questions about whether the change would satisfy the “good 

faith” requirement of 35 U.S.C. § 255, Honeywell explained

that it learned of the incomplete priority chain for the first 

time after the Board issued its decision to institute. Honeywell asserts, and Arkema does not dispute, that Honeywell sought authorization from the Board to file its motion 

for leave “promptly upon discovering the mistake in the 

course of preparing its Patent Owner Responses.” Appellant Br. 50–51. Honeywell sought authorization from the 

Board a little over a year after the ’017 patent issued and 

less than three months after the Board instituted review.

Arkema, on the other hand, argued that the error was 

“not of a minor character and is not proper grounds for correction.” J.A. 176:15–19. Arkema claimed that allowing 

Honeywell to correct this error would be “extremely prejudicial,” because, among other things, Arkema’s window to 

re-file a PGR with different prior art or different references 

had now closed. J.A. 162:4–165:5.

The Board rejected Honeywell’s request for authorization to file a motion for leave, explaining:

The panel has conferred and has determined at this 

juncture there has been a failure to show that [the] 
HONEYWELL INTERNATIONAL INC. v. ARKEMA INC. 5

requirements of 255 have been met. This is not a 

typographical or clerical error. It’s been also failed

[sic] to show that the minor character prong has 

been met. We do not need to reach the issue of 

whether there is a good faith effort here. Furthermore, we believe that to the extent of showing prejudice in this case, it would be improper to allow 

such a motion to be filed at this juncture, due to the 

prejudice that would arise to [Arkema].

J.A. 177:12–178:2.

After rejecting Honeywell’s request, the proceedings 

continued until the Board issued a combined Final Written 

Decision on August 31, 2017. The Board held that 

claims 1–20 of the ’017 patent were unpatentable. 

Honeywell timely appealed. We have jurisdiction under 28 U.S.C. § 1295(a)(4)(A). 

DISCUSSION

Under the Administrative Procedure Act, we “hold unlawful and set aside agency action, findings, and conclusions found to be . . . arbitrary, capricious, an abuse of 

discretion, or otherwise not in accordance with law.” 

5 U.S.C. § 706(2)(A); see In re Chapman, 595 F.3d 1330, 

1336–37 (Fed. Cir. 2010). The Board abuses its discretion 

if the decision: (1) is clearly unreasonable, arbitrary, or fanciful; (2) is based on an erroneous conclusion of law; (3) 

rests on clearly erroneous fact findings; or (4) involves a 

record that contains no evidence on which the Board could 

rationally base its decision. Ultratec, Inc. v. CaptionCall, 

LLC, 872 F.3d 1267, 1273 (Fed. Cir. 2017).

As a preliminary matter, we reject Arkema’s assertion 

that the Board’s decision is unreviewable under 5 U.S.C. 

§ 701(a)(2) as agency action “committed to agency discretion by law.” As we have held, § 701(a)(2) provides a “very 

narrow exception” to the presumption of judicial review, 

and is applicable only “in those rare instances where 
6 HONEYWELL INTERNATIONAL INC. v. ARKEMA INC.

‘statutes are drawn in such broad terms that in a given case 

there is no law to apply.’” Hyatt v. U.S. Patent & Trademark Office, 797 F.3d 1374, 1379 (Fed. Cir. 2015). In Ultratec, we reviewed the Board’s refusal to authorize the 

patent owner to file a motion during a post-grant proceeding. 872 F.3d at 1271–72. We are unpersuaded by 

Arkema’s arguments that we lack the ability to review the 

Board’s refusal to grant authorization in this case. 

On the merits of Honeywell’s appeal, we conclude that 

the Board abused its discretion by assuming the authority 

that 35 U.S.C. § 255 expressly delegates to the Director: to 

determine when a Certificate of Correction is appropriate. 

Patentees may petition the Director to issue a Certificate of Correction to correct in an issued patent “a mistake 

of a clerical or typographical nature, or of minor character,

which was not the fault of the Patent and Trademark Office.” 35 U.S.C. § 255. The patentee must show that the 

mistake “occurred in good faith” and that “the correction 

does not involve such changes in the patent as would constitute new matter or would require re-examination.” Id. 

When a patentee seeks to correct a patent that is subject to a post-issuance review proceeding, the patentee 

must first file a motion with the Board seeking authorization to petition the Director for a Certificate of Correction,

asking the Board to temporarily cede its exclusive jurisdiction over the proceedings. 37 C.F.R. § 1.323; Manual of Patent Examining Procedure (“MPEP”) § 1485; see also 

37 C.F.R. § 42.3(a). Before doing so, the patentee must 

seek authorization from the Board to file the motion for 

leave—as is the case with all motions filed with the Board. 

37 C.F.R. § 42.20(b) (“A motion will not be entered without 

Board authorization.”). 

In other words, a patent owner subject to a post-issuance review proceeding must take three steps in order to 

file a petition for a Certificate of Correction: (1) seek authorization from the Board to file a motion, 37 C.F.R. 
HONEYWELL INTERNATIONAL INC. v. ARKEMA INC. 7

§ 42.20(b); (2) if authorization is granted, file a motion with 

the Board, asking the Board to cede its exclusive jurisdiction so that the patentee can seek a Certificate of Correction from the Director, 37 C.F.R. § 1.323; MPEP § 1485; and 

(3) if the motion is granted, petition the Director for a Certificate of Correction under 35 U.S.C. § 255. E.g., Plastic 

Dev. Grp., LLC v. Maxchief Investments, Ltd., No. IPR2017-

00846, Paper No. 16 at 2 (P.T.A.B. Nov. 13, 2017). After 

those three steps are completed, the Director—not the 

Board—will evaluate the merits of the patentee’s petition, 

including whether the mistake is of “minor character” or 

“occurred in good faith.” See 35 U.S.C. § 255. 

Section 255 does not grant the Board authority to determine whether a mistake in an issued patent is of “minor 

character” or “occurred in good faith.” 35 U.S.C. § 255. 

That authority is expressly granted to the Director. Id. 

The Director has not delegated its Section 255 authority to 

the Board, but has instead promulgated procedures by 

which patentees may seek the Board’s leave to petition the 

Director for a Certificate of Correction. 37 C.F.R. § 1.323; 

MPEP § 1485. 

The Board has previously recognized that § 255 authorizes the Director—not the Board—to determine whether a 

Certificate of Correction should be issued. E.g., Plastic 

Dev. Grp., Paper No. 16 at 2 (“We leave the final determination on whether a Certificate of Correction should be issued with the Director in accordance with the authority 

granted in 35 U.S.C. § 255.”). The Board has likewise recognized that its review of a patentee’s motion for leave to 

seek a Certificate of Correction from the Director does not 

involve a decision about the merits of the patentee’s petition. E.g., United Servs. Auto. Ass’n v. Asghari-Kamrani, 

No. CBM2016-00063, Paper No. 10 at 6 (P.T.A.B. August 

4, 2016) (“USAA”). In USAA, the Board explained: 

[I]n the instant Decision, we are not deciding 

whether a request for a Certificate of Correction
8 HONEYWELL INTERNATIONAL INC. v. ARKEMA INC.

should be granted pursuant to 35 U.S.C. § 255, as 

Patent Owner merely is seeking authorization for 

filing such a request. Moreover, we are not the deciding official for a request for a Certificate of Correction.

Id. 

Instead, the Board has previously reviewed motions for 

leave to seek a Certificate of Correction from the Director 

to “determine whether there is sufficient basis supporting 

Patent Owner’s position that the mistake may be correctable.” Plastic Dev. Grp., Paper No. 16 at 2 (emphasis added). 

We hold that this standard of review is appropriate and 

consistent with 35 U.S.C. § 255, the relevant Board regulations, e.g., 37 C.F.R. §§ 1.323, 42.20(b), 42.3(a); MPEP

§ 1485, and Congress’s intent that the post-issuance proceedings created under the America Invents Act provide 

the PTO with an “enlarged opportunity to correct its errors 

in granting a patent.” Cascades Projection LLC v. Epson 

Am., Inc., 864 F.3d 1309, 1311 (Fed. Cir. 2017).

But in this case, the Board did not review Honeywell’s

motion for leave to seek a Certificate of Correction from the 

Director to determine if Honeywell had demonstrated a 

“sufficient basis” that the mistake “may” be correctable. 

Instead, the Board prohibited Honeywell from even filing a 

motion for leave. The Board refused to authorize Honeywell to file a motion for leave because “at this juncture 

there has been a failure to show that [the] requirements of 

255 have been met.” J.A. 177:12–15. Specifically, the 

Board determined that—based solely on the two telephonic 

hearings—Honeywell “failed to show that the minor character prong has been met.” J.A. 177:17–19. The Board also 

explained that “it would be improper to allow such a motion 

to be filed at this juncture, due to the prejudice that would 

arise to [Arkema].” J.A. 177:22–178:2.

By requiring that Honeywell “show that [the] requirements of 255 have been met” before authorizing Honeywell 
HONEYWELL INTERNATIONAL INC. v. ARKEMA INC. 9

to file a motion for leave to seek a Certificate of Correction

from the Director, the Board abused its discretion. The 

Board further abused its discretion by assuming the authority that § 255 delegates to the Director and deciding 

the merits of Honeywell’s petition for a Certificate of Correction. 

As we held in Ultratec, the Board’s abuse of discretion 

precipitated additional problems. 872 F.3d at 1273. First, 

by evaluating the merits of Honeywell’s § 255 request when 

Honeywell was merely requesting authorization to file a 

motion for leave to petition the Director, the Board “lacked 

the information necessary to make a reasoned decision.” 

Id. At that stage, the Board had not seen the language of 

Honeywell’s proposed correction to the priority chain language of the ’017 patent. Nor had the Board seen any evidence of whether the mistake was inadvertent and made in 

good faith or whether the correction prejudiced Arkema.

The Board also failed to provide an explanation or a 

reasoned basis for its decision. Ultratec, 872 F.3d at 1273

(citing Motor Vehicle Mfs. Ass’n of U.S. v. State Farm Mut. 

Auto. Ins. Co., 463 U.S. 29, 43 (1983) (“[T]he agency must 

examine the relevant data and articulate a satisfactory explanation for its action including a rational connection between the facts found and the choice made.”)). The Board 

provided no explanation for its conclusion that Honeywell 

“failed to show that the minor character prong has been 

met” or its conclusion that prejudice to Arkema required 

denial of Honeywell’s request to file a motion. JA 177:17–

178:6. This failure impedes our meaningful review on appeal. Ultratec, 872 F.3d at 1274 (“For judicial review to be 

meaningfully achieved within these strictures, the agency 

tribunal must present a full and reasoned explanation of 

its decision.”). 

We find nothing in the record, or in the Board’s conclusory decision, that warrants denying Honeywell’s request 

to file a motion for leave to petition the Director for a 
10 HONEYWELL INTERNATIONAL INC. v. ARKEMA INC.

Certificate of Correction correcting the priority chain of

the ’017 patent. Indeed, as Honeywell notes, the PTO has 

previously allowed patentees to correct priority claims 

through Certificates of Correction. Carotek, Inc. v. Kobayashi Ventures, LLC., 875 F. Supp. 2d 313, 331 (S.D.N.Y. 

2012) (“If a patent is issued and contains a mistake, such 

as failing to claim priority to an appropriate earlier-filed 

patent, regardless of whose fault the mistake is, it may be 

corrected by petitioning the PTO for a Certificate of Correction.”); B. Braun Melsungen AG v. Becton, Dickinson & Co., 

No. 1:16-cv-411, 2017 WL 2531939, at *4 (D. Del. June 9, 

2017) (“There is substantial case law supporting Plaintiffs’ 

position that the PTO has a longstanding practice of correcting priority claims through certificates of correction.”). 

The Board never addresses this prior practice, nor does it 

explain why Honeywell’s request is different.

We also express doubt over Arkema’s assertion that 

Honeywell knew about the mistake in priority for at least 

nine months but, to obtain a strategic advantage, declined 

to pursue correction of the mistake. It is unclear how Honeywell would benefit from intentionally delaying its petition to the Director. Because the Board improperly refused 

Honeywell the opportunity to file a motion for leave (and 

Arkema the opportunity to file a response), and then failed 

to explain its conclusion that a motion for leave would be 

improper “due to the prejudice that would arise to Petitioner,” J.A. 177:17–178:6, we are unable to meaningfully 

review the parties’ prejudice arguments.

CONCLUSION

We have considered Arkema’s other arguments and 

find them unpersuasive. We conclude that the Board erred 

by rejecting Honeywell’s request to file a motion for leave 

to petition the Director for a Certificate of Correction based 

on Honeywell’s failure to “show that [the] requirements of 

255 have been met.” We vacate the Board’s final written 

decision and remand to the Board. On remand, the Board 
HONEYWELL INTERNATIONAL INC. v. ARKEMA INC. 11

should authorize Honeywell to file a motion seeking leave 

to petition the Director for a Certificate of Correction. The 

Board should then review Honeywell’s motion for leave in 

accordance with 37 C.F.R. § 1.323 and MPEP § 1485, including to evaluate whether prejudice to Arkema requires 

accommodation.

VACATED AND REMANDED

COSTS

No costs.