269 F.3d 1112 (D.C. Cir. 2001)
Association of Civilian Technicians, Puerto Rico Army Chapter, Petitionerv.Federal Labor Relations Authority, Respondent
No. 00-1486
United States Court of Appeals  FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued October 10, 2001Decided November 9, 2001

On Petition for Review of an Order of the Federal Labor Relations Authority
Daniel M. Schember argued the cause and filed the briefs  for petitioner.
David M. Smith, Solicitor, Federal Labor Relations Authority, argued the cause for respondent.  With him on the  brief were William R. Tobey, Deputy Solicitor, and Judith A.  Hagley, Attorney.
Before:  Sentelle, Randolph and Garland, Circuit Judges.
Opinion for the Court filed by Circuit Judge Sentelle.
Sentelle, Circuit Judge:


1
The Association of Civilian Technicians, Puerto Rico Army Chapter ("the Union"), petitions  this Court for review of the Federal Labor Relations Authority's ("FLRA" or "Authority") decision in which the FLRA  determined that a collective bargaining agreement provision  that seeks reimbursement for out-of-pocket losses resulting  from agency cancellation of previously approved leave is  contrary to law and therefore nonnegotiable.  Petitioner argues that the FLRA erroneously applied the Travel Expenses  Act, 5 U.S.C. § 5701, et seq., to resolve the dispute and failed  to consider whether the provision was authorized under the  collective bargaining law, 5 U.S.C. § 7101, et seq. (Federal  Services Labor-Management Relations Statute).  Because we  agree with the petitioner that the Travel Expenses Act does  not prohibit the proposed provision, we grant the petition for  review, vacate the decision and order of the FLRA, and  remand for proceedings consistent with this opinion.

I. Proceedings Below

2
The Association of Civilian Technicians, a federal employee  labor organization, filed a negotiability appeal with the FLRA  pursuant to 5 U.S.C. § 7105(a)(2)(E), concerning provisions of  a collective bargaining agreement that had been disapproved  by the head of the agency (the Department of Defense) as  contrary to law under 5 U.S.C. § 7114(c).  Specifically, this  case involves the following provision:


3
Once leave has be[en] approved and the employer has a compelling need to cancel the previously approved leave, the employer agrees not to subject the employee to a loss of funds expended in planning of the leave (i.e. hotel reservations, airline tickets, etc.).  The employee will demonstrate the unavoida[bility] of the loss of funds. Ass'n of Civilian Technicians, Puerto Rico Army Ch., 56  F.L.R.A. 493, 496 (2000).  Both the Union and the agency  agreed that this provision would require the Department of Defense to use appropriated funds to reimburse an employee  for certain losses of funds, including (but not limited to) lost  travel expenses, resulting from the agency's cancellation of  previously approved leave.


4
In its statement to the FLRA the agency objected to the  disputed provision on the grounds that the Comptroller General's decisions "consistently held that purely personal expenses, such as forfeited hotel room deposits, dependent's  travel costs, and increased costs for alternate flight reservations, do not become a government obligation upon the cancellation of approved annual leave and may not be reimbursed."  In one of those opinions, the Comptroller General  noted that its "own research ... has not revealed any law or  regulation under which we may authorize payment ... for the  additional personal travel expense incurred."  Matter of: John W. Keys, 60 Comp. Gen. 629 (1981).  Thus the agency  concluded that "language which would agree to payment of  personal expenses as a blanket rule, when annual leave is  cancelled [sic] would create a violation of the Antideficiency  Act."


5
In response to the DOD, the Union noted that the Comptroller General's decisions were not dispositive because they  "by their own terms, do not prohibit collective bargaining  agreements."  The Union accepted the "general principle that  expenditures are not authorized unless a law or regulation  affirmatively authorizes them."  However, it suggested that  the collective bargaining provisions anticipate some expenditures, otherwise, the sweep of this principle "would bar all  proposals costing money unless the expenditure affirmatively  were authorized by law or regulation," a scenario not contemplated by Congress, it argued, given the specificity of the  collective bargaining law.


6
The FLRA affirmed the agency's rejection of this provision  as contrary to law and therefore nonnegotiable.  56 F.L.R.A.  493 (2000).  It first observed that "[t]he disbursement of  appropriated funds must be authorized by statute.  Thus, the  use of appropriated funds to reimburse employees for travel  expenses must be authorized by statute."  Id. at 497 (citations and footnote omitted).  Following this observation, it  noted that "payment of employee travel expenses is governed  by the provisions of the Travel Expenses Act."  Id.  Because  the "Comptroller General administers and interprets the  Travel Expense[s] Act," the Authority "look[ed] for guidance  to decisions of the Comptroller General to determine whether  the Agency has authority to reimburse employees in the  circumstances presented here."  Id.  The FLRA found that  the "Comptroller General has consistently held that purely  personal expenses, such as forfeited hotel room deposits,  dependents' travel costs, and increased costs for alternate  flight reservations, may not be reimbursed upon the cancellation of approved annual leave."  Id. (citing Earl J. Barlow,  Comp. Gen. Decision B-241249 (1991)).  Thus, the Authority  concluded that "given the nature of the reimbursement at  issue in this case, we agree with the Comptroller General that  no authority exists for agencies to use appropriated funds to  reimburse employees for purely personal expenses involved in  the planning of leave."  Id.


7
The Union filed a motion for reconsideration before the  FLRA in which it argued that the Travel Expenses Act was  inapplicable.  It further argued that the expenditures that  would be required by the disputed provision "are authorized  by the collective bargaining law, [5 U.S.C. § 7101, et seq.],  and therefore by the law that generally authorizes agency  expenditures."  The Union cited two FLRA decisions, NTEU  and Department of the Treasury, BATF, 26 F.L.R.A. 497  (1987);  and NFFE and GSA, 24 F.L.R.A. 430 (1986), which it  argued stood for the proposition that the "collective bargaining law creates new agency obligations which general agency  appropriations may be used to meet."  In the order denying  the motion for reconsideration, 56 F.L.R.A. 807 (2000), the  FLRA noted that the "Union contends that the Authority  erroneously applied the Travel Expenses Act and Federal  Travel Regulations" and that the Union believes that " 'general agency appropriations ... may be used to meet obligations  of collective bargaining agreements' when those agreements  are 'reasonably related' to the purpose of the collective bargaining law."  56 F.L.R.A. at 807.  The Authority dispensed  with the Union's arguments as follows:


8
The Union's first argument is that the Authority erroneously applied the Travel Expenses Act and its implementing Federal Travel Regulations in finding that the provision is contrary to law.  By its own terms, however, the provision requires the Agency, among other things, to reimburse employees for hotel reservations and airline tickets....  The provision clearly requires the Agency to pay employees for lost travel expenses.  Accordingly, in [the case below] Puerto Rico National Guard, we applied Comptroller General decisions which have interpreted the Federal Travel Regulations to hold that agencies have "no authority" to reimburse employees for the kind of purely personal travel expenses that are set forth by the terms of the provision. Id. at 808.


9
Finally, the FLRA addressed the Union's "further  argu[ment] that 'the collective bargaining law' authorizes the  Agency to negotiate over the provision" and concluded that  "[b]ecause there is no duty to bargain over a provision that is  contrary to law, we reject the Union's argument."  Id.  The  Authority responded, in a footnote, to the decisions cited by  the Union by observing that "[c]onsistent with those cases, it  is well accepted that agencies are required to negotiate on  matters pertaining to the conditions of employment of unit  employees that are within the discretion of the agency under  law and are not otherwise nonnegotiable.  In contrast, however, the provision in this case has been demonstrated to be  contrary to law."  Id. n.5 (citations omitted).


10
The Union sought review in this Court.

II. Analysis

11
In reviewing the FLRA's interpretation of its own enabling  statute, we are "mindful that we owe great deference to the  expertise of the Authority as it 'exercises its special function  of applying the general provisions of the Act to the complexities of federal labor relations.' "  NLRB Union, Local 6 v.  FLRA, 842 F.2d 483, 486 (D.C. Cir. 1988) (quoting BATF v.  FLRA, 464 U.S. 89, 97 (1983)).  Here, however, we are faced  with the FLRA's interpretation of the Travel Expenses Act, a  statute not committed to the Authority's administration.  We  review such purely legal questions de novo.  See Social  Security Admin. v. FLRA, 201 F.3d 465, 471 (D.C. Cir. 2000)  ("We do not defer to the FLRA's interpretation of ... a  general statute not committedto the Authority's administration.").  The Authority's reliance on opinions of the Comptroller General does not change our analysis.  As we have held,  "we regard the assessment of the GAO [and thus, the Comptroller General] as an expert opinion, which we should prudently consider but to which we have no obligation to defer." Delta Data Systems Corp. v. Webster, 744 F.2d 197, 201 & n.1  (D.C. Cir. 1984) (Scalia, J.) (concluding that "[s]ince the GAO  has been thought to be 'an arm of the legislature,' there  might be a constitutional impediment to such binding effect"  (citation omitted));  cf. Crandon v. United States, 494 U.S.  152, 177 (1990) ("[T]he vast body of administrative interpretation that exists--innumerable advisory opinions not only of  the Attorney General, the OLC, and the Office of Government  Ethics, but also of the Comptroller General and the general  counsels for various agencies--is not an administrative interpretation that is entitled to deference under Chevron...."). With that standard of review in mind, we turn to the Authority's decision.


12
The FLRA's decision was premised on the assumption that  the Travel Expenses Act governs the disputed provision in  the collective bargaining agreement.  It does not.  The disputed provision says that "[o]nce leave has be[en] approved  and the employer has a compelling need to cancel the previously approved leave, the employer agrees not to subject the  employee to a loss of funds expended in the planning of the  leave," and gives costs incurred from hotel reservations and  airline tickets as examples.  56 F.L.R.A at 496 (emphasis  added).  That provision does not speak in terms of travel  expenses, personal, official, or otherwise.  As the Union  notes, it requires the agency to "pay employees' out-of-pocket losses (whether or not travel-related) when the agency-acting for its convenience, and in its interest--exercises its  management right under 5 U.S.C. § 7106(a)(2)(B) to cancel  leave and assign work instead."  In contrast, the Travel  Expenses Act, and specifically 5 U.S.C. § 5702, the provision  in question, only governs per diem and reimbursement when  an employee is "traveling on official business."  The Union  proposal does not necessarily even involve canceled travel,  and it certainly does not address official business.


13
The FLRA cannot cite a single provision within the Travel  Expenses Act, much less § 5702, that prohibits the disputed  provision, expressly or impliedly.  The Act addresses different subject matter altogether.  It authorizes official travel. It does not by its terms prohibit anything.  The Authority is  attempting to force a square peg into a round hole. No  faithful reading of the Travel Expenses Act, which establishes  "entitled" reimbursement or allowance "when traveling on  official business," 5 U.S.C. § 5702(a)(1), is relevant to the  disputed provision, which provides compensation for unavoidable expenses resulting from canceled leave.  To force such a  reading turns the Travel Expenses Act on its head.


14
This is not to say that the expenditure of appropriated  funds in a manner not authorized by law is negotiable--it is  not.  In an attempt to salvage its decision, the Authority now  argues that its decision was based on the general principle  that expenditures are not authorized unless a law or regulation affirmatively authorizes them, and that there is no authorization for the expenditure required by the disputed provision.  But the Authority's decision was not based on a lack of  authorization for the expenditure.  Rather, it is clear that the  FLRA's decision reasoned that because the Travel Expenses  Act did not authorize the expenditure, it was prohibited. The  Authority offered no other reason. Specifically, it did not rely  on the lack of authorization elsewhere in governing law.  Agency decisions must generally be affirmed on the grounds  stated in them.  See, e.g., Fort Stewart Schools v. FLRA, 495  U.S. 641, 651-52 (1990) ("[I]t is elementary that if an agency's  decision is to be sustained in the courts on any rationale  under which the agency's factual or legal determinations are entitled to deference, it must be upheld on the rationale set  forth by the agency itself.");  SEC v. Chenery Corp., 318 U.S.  80, 93-95 (1943).  Post-hoc rationalizations, developed for  litigation are insufficient.  See Burlington Truck Lines, Inc.  v. United States, 371 U.S. 156, 168 (1962) ("The courts may  not accept appellate counsel's post hoc rationalizations for  agency action....").  If the Authority only based its decision  on the Travel Expenses Act, then that is the only rationale we  may consider.


15
In its original opinion below, under "Analysis and Conclusions," the FLRA begins its analysis as follows:  "The disbursement of appropriated funds must be authorized by  statute. Thus, the use of appropriated funds to reimburse  employees for travel expenses must be authorized by statute." 56 F.L.R.A. at 497 (emphasis added).  The FLRA clearly saw  the provision as one involving travel expenses and treated it  as squarely governed by the Travel Expenses Act.  Because  the Travel Expenses Act did not authorize these expenditures, it concluded (following the Comptroller General's opinions), that there was no authority for the disputed provision,  and declared it nonnegotiable.  That proves at most that the  Travel Expenses Act cannot be the source of authority for the  disputed provision, not that the provision is contrary to law. However, the Union does not rely on the Travel Expenses  Act as a source of authority--quite to the contrary, it expressly argues that the Act is inapplicable, instead relying on  the collective bargaining laws as authorizing resulting expenditures.  The FLRA did not address this argument.


16
The argument that the collective bargaining laws themselves authorize the expenditure is one reason that the Comptroller General opinions relied on by the FLRA cannot resolve this case.  Those opinions did not address a collective  bargaining situation and did not consider what effect, if any,  the collective bargaining laws would have in authorizing the  disputed provision.  See 56 F.L.R.A. at 497 (discussing Comptroller General opinions). Reliance on these opinions of the  Comptroller General is flawed for yet another reason.  To the  extent that the these opinions stand for the proposition that  " 'there is no authority' to reimburse [an] employee for additional personal travel expenses incurred when employee's  official duties caused him to make alternative flight reservations," 56 F.L.R.A. at 497 (quoting John W. Keys, 60 Comp.  Gen. 629)) (1981), they must be read narrowly.  This pronouncement would necessarily only apply to the agency before the Comptroller General at that time--the Department  of the Interior (in the Keys matter), not the Department of  Defense, as we have here.  Moreover, any subsequent appropriations acts would, of course, render that opinion, expert  though it may have been at the time, obsolete.  Therefore the  FLRA should have confronted the specific facts before it--a  collective bargaining agreement provision, with the DOD, in  the year 2000.  It did not, either in its original order or the  order denying reconsideration.


17
In its motion for reconsideration, the Union expressly  argued that the expenditures required by the disputed provision "are authorized by the collective bargaining law, [5  U.S.C. § 7101, et seq.], and therefore by the law that generally authorizes agency expenditures." (emphasis added).  Yet  again, however, the Authority failed to address this argument. Instead it relied on its position that the "provision clearly  requires the Agency to pay employees for lost travel expenses," and noted that in the original decision it "applied  Comptroller General decisions which have interpreted the  Federal Travel Regulations to hold that agencies have 'no  authority' to reimburse employees for the kind of purely  personal travel expenses that are set forth by the terms of  the provision."  56 F.L.R.A. at 808 (emphasis added).  The  FLRA was only "appl[ying]" a rule that under the Travel  Expenses Act and corresponding regulations, there is no  authority to reimburse personal travel expenses or expenses  that arise from canceled leave, and that rule does not dispose  of the Union's argument that the collective bargaining laws  and laws that generally authorize agency expenditures provide an independent source of authority.  Instead, the FLRA  acknowledges the Union's "further argu[ment] that 'the collective bargaining law' authorizes the Agency to negotiate  over the provision" only to respond that "[b]ecause there is no  duty to bargain over a provision that is contrary to law, we reject the Union's argument."  Id.  The FLRA cannot now  argue that its decision was based on the general proposition  that expenditures must be authorized, because after reaching  the conclusion that there is no duty to bargain over a provision that is contrary to law, the Authority clearly states in a  footnote:  "In light of this result, it is unnecessary for the  Authority to address the Union's additional arguments."  Id.  at 808 n.6.  These unaddressed "additional arguments" included the Union's position that the collective bargaining laws  themselves permitted the use of general agency appropriations to meet the obligations of bargaining.  See id. at 807-08. Despite its protestations to the contrary, the Authority only  considered whether the disputed provision was prohibited by  the Travel Expenses Act.  Because the FLRA's application of  the Travel Expenses Act was erroneous we must grant the  petition for review.

III. Conclusion

18
On remand, the Authority should consider whether the  expenditures required by the disputed provision are "authorized by the collective bargaining law," 5 U.S.C. § 7101, et  seq., or are specifically authorized as an "appropriate arrangement[ ] for employees adversely affected by the exercise of  [agency management] authority" in canceling leave and "assign[ing] work," 5 U.S.C. §§ 7106(a)(2)(B), (b)(3), as argued  by the Union.  That question is not properly before this  Court because the FLRA based its decision solely on a  misinterpretation of the Travel Expenses Act, and we decline  to address it.  Similarly, whether the Union failed to, or even  needed to cite a general agency appropriations bill in the  FLRA proceedings is also not before us.  The only issue  confronting this Court is the validity of the FLRA's decision--that the Travel Expenses Act prohibits the disputed  provision.  Because it does not, we grant the petition for  review, vacate the decision and order below, and remand for  proceedings consistent with this opinion.

