United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued November 21, 2016 Decided March 7, 2017

No. 15-1299

ABM ONSITE SERVICES - WEST, INC.,

PETITIONER

v.

NATIONAL LABOR RELATIONS BOARD,

RESPONDENT

INTERNATIONAL ASSOCIATION OF MACHINISTS AND 

AEROSPACE WORKERS, DISTRICT LODGE W24 AND LOCAL 

LODGE 1005,

INTERVENOR

Consolidated with 15-1347

On Petition for Review and Cross-Application

for Enforcement of an Order of 

the National Labor Relations Board

Douglas W. Hall argued the cause and filed the briefs for 

petitioner.
2

Amy H. Ginn, Attorney, National Labor Relations Board, 

argued the cause for respondent. With her on the brief were 

Richard F. Griffin, Jr., General Counsel, John H. Ferguson, 

Associate General Counsel, Linda Dreeben, Deputy Associate 

General Counsel, and Usha Dheenan, Supervisory Attorney.

David L. Neigus argued the cause and filed the brief for 

intervenor International Association of Machinists and 

Aerospace Workers, District Lodge W24 and Local Lodge

1005 in support of respondent. Mark D. Schneider and William 

H. Haller entered appearances.

Before: GRIFFITH, SRINIVASAN, and MILLETT, Circuit 

Judges.

Opinion for the court filed by Circuit Judge GRIFFITH.

GRIFFITH, Circuit Judge: This petition for review 

challenges the determination of the National Labor Relations 

Board that a union’s effort to represent the workers who handle 

airline baggage is governed by the National Labor Relations 

Act and not the Railway Labor Act. In reaching its conclusion, 

the Board departed from its precedent without offering a 

rationale for its new approach. We therefore vacate the Board’s 

order and remand the matter for further proceedings.

I

A

The National Labor Relations Act, 29 U.S.C. §§ 151 et 

seq., regulates most private-sector labor relations. Concerned, 

however, that labor strife in the railway and airline industries 

could disrupt commerce nationwide, Congress expressly 

carved out these industries, which were already covered by the 
3

Railway Labor Act, from coverage under the NLRA 

framework when it passed the NLRA. See id. § 152; see also 

Tex. & New Orleans R.R. v. Bhd. of Ry. & S.S. Clerks, 281 U.S. 

548, 565 (1930) (remarking that “the major purpose of 

Congress in passing the Railway Labor Act was to provide a 

machinery to prevent strikes”).

1 The Act creates a “special 

scheme” for the railway and airline industries, premised on 

“their unique role in serving the traveling and shipping public 

in interstate commerce.” Verrett v. SABRE Grp., Inc., 70 F. 

Supp. 2d 1277, 1281 (N.D. Okla. 1999). Under this separate 

regulatory scheme, various mediation and arbitration boards 

work to resolve airline and railway labor disputes that could 

interrupt interstate commerce. See id.

The question of which labor scheme governs has

meaningful consequences for both employers and employees. 

Chief among them are the different powers Congress has given 

the agencies that administer the relevant statutes. For example, 

the NLRB can initiate unfair-labor-practice proceedings and 

issue orders to employers, but the National Mediation Board 

(NMB), which administers the RLA, performs no lawenforcement function. The NMB’s role is limited mainly to 

determining whether employees in the airline and railway 

industries have chosen union representation and then mediating 

collective bargaining. In addition, under the RLA, both 

employers and employees must exhaust an extended 

negotiation and mediation process before they can lawfully 

resort to self-help measures, such as unilaterally altering 

working conditions or calling a strike. This prolonged process 

 1 Although the RLA initially applied only to rail carriers, “[a]ir 

carriers and their employees were made subject to the . . . Act in 

1936.” Bhd. of R.R. Trainmen v. Jacksonville Terminal Co., 394 U.S. 

369, 381 n.16 (1969) (citing 45 U.S.C. §§ 181-182).
4

is designed to avoid strikes and “keep transportation moving”

in the specific subset of the American economy that concerns 

the RLA. Pan Am. World Airways, Inc. v. United Bhd. of 

Carpenters & Joiners of Am., 324 F.2d 217, 220 (9th Cir. 

1963). Under the NLRA, by contrast, employers and 

employees have much more latitude to engage in self-help. 

Employees often prefer to organize under the NLRA, as it 

protects a wider array of “concerted activity” by employees 

than does the RLA. See Beckett v. Atlas Air, Inc., 968 F. Supp. 

814, 820 (E.D.N.Y. 1997) (citing cases).

The RLA originally covered only common carriers, but 

Congress expanded the Act in 1934 to cover certain companies 

that perform transportation-related services for those carriers. 

As a result, a company is subject to the RLA and falls outside 

the jurisdiction of the NLRB if it “is directly or indirectly 

owned or controlled by or under common control with any 

carrier” and “operates any equipment or facilities or performs 

any service” related to transportation. 45 U.S.C. § 151. 

Whether a company is controlled by a carrier, however, is often 

unclear. Thus, “the NLRB and the NMB have, in the absence 

of any statute addressing the point, jointly developed their own 

method for determining their mutual jurisdictional question of 

whether the NLRA or the RLA governs” in any given case. 

United Parcel Serv., Inc. v. NLRB, 92 F.3d 1221, 1223 (D.C. 

Cir. 1996).

The NLRB frequently refers the jurisdictional question to 

the NMB for an advisory opinion and then defers to the NMB’s 

view, based on the NMB’s expertise in administering the RLA. 

See United Parcel Serv., Inc., 318 N.L.R.B. 778, 780 (1995) 

(referring cases to the NMB “enables the [NLRB] to obtain the 

NMB’s expertise on jurisdictional matters most familiar to it”), 

aff’d, 93 F.3d 1221 (D.C. Cir. 1996); Pan Am. World Airways, 

Inc., 115 N.L.R.B. 493, 495 (1956) (explaining the NLRB’s 
5

view of the NMB’s primacy in resolving jurisdictional 

questions that implicate the RLA). The NLRB follows this 

accepted practice when a party raises a colorable claim that the 

NLRB lacks jurisdiction. See Spartan Aviation Indus., 337 

N.L.R.B. 708, 708 (2002) (“When a party raises a claim of 

arguable jurisdiction under the RLA, the Board generally refers 

the case to the National Mediation Board . . . for an advisory 

opinion. . . .”). This practice dates back to at least 1956. See 

Pan Am. World Airways, Inc., 115 N.L.R.B. at 495 (declining 

to assert jurisdiction in a case over which the NMB claimed 

jurisdiction). An exception exists to the general rule, however: 

under “long-standing practice,” the NLRB will not refer

jurisdictional questions to the NMB in situations where NMB 

precedent provides a clear answer. United Parcel Serv., Inc., 

92 F.3d at 1228. 

B

The airlines that fly into and out of the Portland 

International Airport formed the Portland Airlines Consortium 

(“PAC” or “the Consortium”) to operate the airport’s baggagehandling system. Since 2011, the Consortium has retained 

ABM Onsite Services – West (“ABM” or “the Company”), an 

independent contractor, to run the system.

2 The issue in this 

case is whether ABM is a “carrier” under the RLA and thus 

falls outside the NLRB’s jurisdiction. The answer turns on the 

degree of control that the Consortium exercises over the 

Company. To assess that control, it is important to understand

the extent of the Consortium’s contractual and practical 

involvement in a number of areas: how ABM employees do 

 2 These facts are drawn from the findings made by the NLRB’s 

regional director or come directly from the contract.
6

their jobs, how they are trained, what equipment they use, and 

even how they dress. 

Most notably, the contract allows the Consortium to 

establish all standard operating procedures and provide all 

operating manuals for ABM. These manuals serve as the basis 

for ABM employee training. The contract also allows the 

Consortium to keep a close eye on the performance of ABM 

and its employees. For example, the Company is required to 

provide the Consortium with access to documents dealing with

its operations, its compliance with non-discrimination laws, its

operations and maintenance safety plans, and reports of on-thejob accidents.

In addition, the contract enables the Consortium to 

exercise influence over the Company’s personnel decisions. 

All of the Company’s staffing plans, for instance, must be 

approved by the Consortium before taking effect, and the 

Consortium’s general manager must approve overtime work by 

ABM employees. Importantly, the Consortium also has the 

right to approve any changes in the Company’s “key 

personnel,” and to direct the company to remove employees

from the contract. The contract does not, however, authorize 

the Consortium to discipline the Company’s employees

directly or require the Company to consult with it about 

discipline.

Furthermore, the contract specifies that the Consortium is 

to provide the Company with certain equipment, such as 

electric vehicles to move baggage and industrial bicycles to get 

around the baggage-handling system. The Consortium also 

must provide, free of charge, office space for the Company at 

the airport. Finally, the contract dictates that ABM employees 

meet certain appearance standards and wear uniforms that 

display the Consortium’s logo, rather than the logo of ABM.
7

C

In January 2015, the International Association of 

Machinists (the Union) filed a petition with the NLRB seeking 

to represent ABM’s “jammer technicians,” who ensure that 

passenger bags get from the airlines’ ticket counters to the 

aircraft, and its dispatchers, who take calls from airline 

employees regarding baggage issues and are the primary point 

of contact with the airlines. The Company protested that the 

NLRB lacked jurisdiction over the matter because the 

Company was subject to the RLA, not the NLRA. In the 

alternative, the Company argued, the NLRB should refer the 

jurisdictional question to the NMB for an advisory opinion. To 

resolve that jurisdictional question, the NLRB’s regional 

director held a hearing at which the Company’s facility 

manager and branch manager testified, along with two 

dispatchers. The regional director found that the Consortium

did not exercise control over the Company and its employees 

within the meaning of the RLA and concluded that the NLRB

thus had jurisdiction over the matter. The Company sought 

review of the order by the NLRB itself, which summarily 

denied the Company’srequest and affirmed its own jurisdiction

in a 2-to-1 decision. The majority determined that the petition 

raised “no substantial issues warranting review.” J.A. 608. The 

dissenting member, however, was not satisfied that the Board

had jurisdiction, writing that “substantial evidence [exists] that 

the Portland Airlines Consortium is involved in [the 

Company]’s personnel decisions and operations, which may 

have been afforded insufficient weight by the Regional 

Director.” J.A. 608.

That same day, a majority of ABM’s participating 

employees voted in favor of union representation. The NLRB 

certified the Union as the employees’ collective-bargaining 

representative. To challenge the Board’s jurisdictional ruling, 
8

the Company refused to bargain with the Union, which drew 

an unfair-labor-practice charge from the Union and a complaint 

from the regional director of the NLRB. The NLRB granted 

summary judgment against the Company, which then filed this

petition for review. The NLRB cross-applied for enforcement 

of its order, and the Union subsequently intervened.

We have jurisdiction under 29 U.S.C. §§ 160(f) and

160(e).

II

This case turns on the fundamental principle that an 

agency may not act in a manner that is “arbitrary, capricious, 

an abuse of discretion, or otherwise not in accordance with 

law.” 5 U.S.C. § 706(2)(a). The NLRB has violated that 

cardinal rule here by applying a new test to determine whether 

the RLA applies, without explaining its reasons for doing so. 

Because an agency’s unexplained departure from precedent is 

arbitrary and capricious, we must vacate the Board’s order. 

Comcast Corp. v. FCC, 526 F.3d 763, 769 (D.C. Cir. 2008) 

(citing Pontchartrain Broad. Co. v. FCC, 15 F.3d 183, 185 

(D.C. Cir. 1994)).

A

Any company that is “directly or indirectly owned or 

controlled by” an airline is governed by the RLA, 45 U.S.C. 

§ 151, provided that the company’s employees do work “that 

is traditionally performed by employees of . . . air carriers,” Air 

Serv Corp., 33 N.M.B. 272, 284 (2006). No party takes issue 

with the NMB’s interpretation on that latter point or disputes 

that ABM employees do work that is traditionally performed 

by employees of air carriers. As a result, because ABM is not 
9

owned by air carriers, the only question in this case is whether 

it is controlled by them.

In 1980, the NMB began “an extensive evaluation of its 

jurisdictional standards,” including on the issue of control, “in 

light of changing corporate relationships and increasing use of 

contractors to perform work integral to rail and air 

transportation.” Bhd. Ry. Carmen of the U.S. & Can., 8 N.M.B. 

58, 61 (1980). Over the ensuing years, the NMB developed a 

list of six factors to guide it in determining whether a company 

is controlled by an air carrier. See, e.g., Miami Aircraft Support, 

21 N.M.B. 78, 81 (1993). As stated most directly by the NMB 

in 2006, the agency looked to (1) the extent of the carrier’s

control over the manner in which the company conducts its 

business; (2) the carrier’s access to the company’s operations 

and records; (3) the carrier’s role in the company’s personnel 

decisions; (4) the degree of carrier supervision of the 

company’s employees; (5) whether company employees are 

held out to the public as carrier employees; and (6) the extent 

of the carrier’s control over employee training. See Air Serv

Corp., 33 N.M.B. at 285.

As framed by the NMB in that case, the “standard for 

satisfying” this test was “the degree of influence that a carrier 

has over discharge, discipline, wages, working conditions and 

operations,” as opposed to any kind of requirement “that a 

carrier hire, fire, set wages, hours and working conditions of 

contractor employees.” Id. (emphasis added); see also Roca v. 

Alphatech Aviation Servs., Inc., 961 F. Supp. 2d 1234, 1240 

(S.D. Fla. 2013) (explaining that control under the RLA would 

exist under the “NMB’s . . . test [when the] ‘carrier controls the 

details of the day-to-day process by which the contractor 

provides services—for example, the number of employees 

assigned to particular tasks, the employees’ attire, the length of 

their shifts, and the methods they use in their work.’” (quoting 
10

Cunningham v. Elec. Data Sys. Corp., No. 06-cv-3530 (RJH), 

2010 WL 1223084, at *6 (S.D.N.Y. Mar. 30, 2010))). In other 

words, for the NMB to find the type of control that would 

trigger the jurisdiction of the RLA, an air carrier did not have 

to dictate decisions over employee discharge, discipline, 

wages, working conditions, and operations; it simply had to 

exercise some significant influence over those aspects of the 

employment relationship.

Under this test, ABM would plainly fall under the control 

of air carriers. The NLRB does not even attempt to argue 

otherwise. Indeed, the NMB previously found control and 

jurisdiction with facts similar to these for many airline-services 

contractors. In fact, according to one commentator, the NMB 

“found RLA jurisdiction in all but one of over thirty [such]

airline-control cases” it considered between the mid-1990s and

2011. Brent Garren, NLRA and RLA Jurisdiction over Airline 

Independent Contractors: Back on Course, 31 ABA J. LAB. &

EMP. L. 77, 93 (2015).

Air Serv Corp. is an especially clear example of how that 

agency used to find carrier control over contractors like ABM. 

With apologies to the reader for the lengthy excerpt, the 

NMB’s discussion of the key facts in Air Serv shows that there 

is little daylight between that contractor’s situation and 

ABM’s:

United’s flight schedules affect the work 

schedules of Air Serv employees. United 

establishes a minimum level of staffing. United 

provides and repairs the equipment used by Air 

Serv to service the Carrier’s aircraft. United 

provides many of the supplies Air Serv uses to 

service the aircraft. United specifies the 

cleaning supplies which must be used to clean 
11

its aircraft. In order to perform periodic security 

and safety audits, United has access to Air 

Serv’s records regarding personnel, 

maintenance, and training. United’s [internal]

regulations appear, by reference, to be an 

extensive set of regulations and standards that 

must be adhered to under the terms of the 

Services Agreement. Through [its internal]

regulations[,] United dictates the cleaning 

guidelines and procedures for servicing the 

aircraft. Air Serv has very little discretion 

concerning how or when to provide service.

 Although Air Serv supervises its own 

employees, United exercises a great deal of 

control over Air Serv employees through its 

comprehensive monitoring of the contract’s 

performance. This monitoring includes: 

monetary performance penalties, minimum 

staffing levels, daily vendor meetings, detailed 

. . . regulations and regular audits.

Air Serv Corp., 33 N.M.B. at 285-86. 

Indeed, there is no meaningful distinction between the 

control United exercised over Air Serv and the control carriers 

exercise over ABM. Here, the carriers’ flight schedules 

determine the work schedules of the Company’s employees. 

The Consortium decides when, where, and how many 

employees work at a time. It provides much of the equipment 

the Company uses, along with office space. The Consortium

specifies the exact procedures by which ABM employees do

their jobs, and it has access to ABM employee-training and 

qualifications records. The Consortium’s general manager 

directly trains ABM employees on bag hygiene, and when the 
12

general manager does not do the training himself, the 

Consortium still provides the training materials and dictates the 

procedures to be followed. And even though ABM supervises 

its own employees, the Consortium wields a great deal of 

influence in practice through its comprehensive monitoring of 

the contract’s performance. If anything, carriers appear to 

exercise more control over ABM than United did over Air 

Serv, given the Consortium’s contractual right to approve 

changes in key ABM personnel, its control over the appearance 

of ABM employees, and the fact that the Consortium places its 

own logo on ABM employees’ uniforms.

Had the NLRB followed the NMB’s analysis in Air Serv,

there is no question that ABM would be covered by the RLA

and that the NLRB would have no jurisdiction over this labor 

dispute. Indeed, even in prior cases where carrier influence

over personnel decisions was a factor weighing in favor of a 

finding of control, the NMB never went so far as to hold that 

the ability to discipline or discharge company personnel was 

necessary or even that it was a factor to be given significantly

greater weight than the others. See, e.g., Complete Skycap 

Servs., Inc., 31 N.M.B. 1, 5 (2003) (listing the fact that carriers 

“may request removal of an employee” as merely one of the 

many factors favoring a finding of control). Moreover, in the 

past, the NMB had found control even where there was no

indication that an airline “ha[d] the right to request employee 

discipline or removal” and where “there [was] no evidence that 

[the airline] ha[d] []ever requested [the contractor] to discipline 

or remove an employee.” Kanonn Serv. Enters. Corp., 31 

N.M.B. 409, 417 (2004).

3 If the ability to dictate personnel 

actions (especially negative ones) had been a necessary 

 3 The NMB has never directly overruled or even disavowed 

these decisions. See Garren, supra, at 102-03.
13

condition for finding RLA-level control, the NMB would have 

reached the opposite result in such cases. By the same token, 

had the NLRB followed the reasoning used in those cases here, 

it would have concluded that the RLA governed the dispute 

with ABM even though the airlines cannot discipline or 

effectively fire ABM’s employees.

In a clear departure from precedent, however, the NMB in 

2013 began requiring that air carriers exercise a substantial 

“degree of control over the firing[] and discipline of a 

company’s employees” before it would find that company 

subject to the RLA. Huntleigh USA Corp., 40 N.M.B. 130, 137

(2013); see also Aero Port Servs., Inc., 40 N.M.B. 139, 143

(2013) (finding that a cargo-screening company was not 

subject to air-carrier control, based on a lack of direct 

involvement by the airlines in employee discipline).4 The 

NMB made no effort to explain this change to its test for RLA 

jurisdiction. The agency expanded on this approach later that 

year in Bags, Inc., where it found especially relevant that the 

employer made the final disciplinary decisions, even though 

airlines could provide “input” into the process. See 40 N.M.B.

165, 170 (2013). The NMB determined that meaningful control 

was lacking even though, in this line of cases, carriers provided 

training and operating-procedure manuals, Menzies Aviation, 

Inc., 42 N.M.B. 1, 2 (2014); determined staffing levels, id. at 

 4 The NMB also emphasized that Aero Port Services’ contract 

involved “the type of control expected in nearly any contract for 

services.” 40 N.M.B. 139, 143 (2013). Although the NMB did not 

explain what a typical contract for services looks like, it subsequently 

recited similar language in Bags, Inc., where it observed that “the 

type of control exercised by the [airlines] over [the employer] is 

found in almost any contract between a service provider and a 

customer.” 40 N.M.B. 165, 170 (2013). The NMB has continued to 

use this language ever since. See Menzies Aviation, Inc., 42 N.M.B. 

1, 4, 7 (2014); Airway Cleaners, LLC, 41 N.M.B. 262, 268 (2014).
14

4; Aero Port Servs., 40 N.M.B. at 141; controlled scheduling,

Bags, Inc., 40 N.M.B. at 170; provided equipment and space, 

id.; Menzies Aviation, 42 N.M.B. at 2; recommended 

promotions, Airway Cleaners, LLC, 41 N.M.B. 262, 266 

(2014); and possessed veto authority over material changes to 

contractors’ staff, id. at 265.

We are not the first to remark on this shift in the NMB’s

analysis. In an order issued just two months before the NLRB 

granted summary judgment against ABM, an NLRB member 

observed “that in . . . recent cases, the National Mediation 

Board . . . ha[d] issued advisory opinions to the NLRB 

declining jurisdiction, despite air carriers providing detailed 

specifications as to the employer’s performance of work 

traditionally performed by carriers (and their auditing that 

performance).” Primeflight Aviation Servs., Inc., 12-RC113687, 2015 WL 3814049, at *1 n.1 (June 18, 2015)

(describing the view of Board Member Harry I. Johnson, III). 

In that member’s assessment, “these cases represent[ed] a shift 

by the NMB from earlier opinions in which it had asserted 

jurisdiction on similar grounds.” Id.

In 2014, a member of the NMB noted the same change:

“In recent cases where the [National Mediation] Board has 

declined to find jurisdiction over similar companies, it [has]

generally relied on the absence of substantial control over ‘the 

firing and discipline of a company’s employees . . . .’” Airway 

Cleaners, 41 N.M.B. at 275-76 (2014) (Geale, Mem.,

concurring in part and dissenting in part) (quoting Huntleigh 

USA Corp., 30 N.M.B. at 137). “Those cases,” Board Member 

Nicholas Geale explains, “appear to overly emphasize that 

aspect compared to [earlier] NMB precedent.” Id. Member 

Geale reiterated those concerns later that year, dissenting from 

another NMB advisory opinion. See Menzies Aviation, Inc., 42 

N.M.B. at 8 (Geale, Mem., dissenting) (confessing “difficulty 
15

understanding what, if any, evidence could convince [the 

NMB] of coverage under our traditional . . . test”). The NMB’s 

decision to find no control in Menzies Aviation is remarkable 

in light of its prior decisions because, as Member Geale 

observes, the airline in that case had the right to demand the 

removal of particular vendor employees from the contract. See 

id. (Geale, Mem., dissenting). These cases and commentary

from members of both boards demonstrate that, under the test 

the NMB now applies, the NMB will not find control for RLA

purposes if the contractor is ultimately allowed “to determine 

the appropriate discipline” for its own employees. See id. at 6

(majority opinion). That rule is impossible to square with cases 

from just a few years earlier. Cf. Garren, supra, at 103 (noting 

that the NMB’s decisions in Airway Cleaners and other recent 

cases “seem[] inconsistent with [the] more than thirty decisions 

from 1996-2011 that found RLA jurisdiction” under similar 

facts).

In ABM’s case, the NLRB found “that the record did not 

establish whether an employee’s removal from service” at the 

airport—which the Consortium has the right to request or 

require under certain circumstances—“would effectively result 

in the employee’s discharge” from the company. J.A. 568. The 

NLRB also emphasized that the Company “conducts its own 

investigations of [its] employees” before doling out discipline.

J.A. 568. Under those facts, the most recent NMB precedent

(on its own) might justify the NLRB’s determination that 

carriers exercise insufficient control over ABM for the RLA to 

apply. See Menzies Aviation, 42 N.M.B. at 6 (explaining that 

“the authority to remove employees” from a contract is relevant 

only when “an employee has been terminated following a 

carrier request that he or she be removed from the contract” 

(emphasis added)). After all, it is far from clear that the 

Consortium has the power to determine discipline for ABM 
16

employees or to ensure that those employees are fired from the 

Company (and not just removed from service at the airport).

And that is the very reasoning the NLRB used to conclude

that the RLA did not apply here. See J.A. 571 (citing Menzies 

Aviation, Inc., 42 N.M.B. 1; Airway Cleaners, LLC, 41 N.M.B.

262; and Bags, Inc., 40 N.M.B. 165) (finding PAC’s ability to 

discipline and discharge ABM employees lacking and 

observing “that the degree of control that PAC has over [ABM] 

is contractually no greater than the type of control exercised in 

a typical subcontractor relationship”). Yet the NMB never

expressly disavowed its precedent that took all six factors into 

account when determining whether a carrier controlled a 

contractor. Nor did the NMB ever explain why it decided to 

replace that traditional approach with an analysis that 

emphasized carrier control of discipline and discharge. Given

the NLRB’s previous endorsement of the prior approach, see, 

e.g., Aircraft Serv. Int’l Grp., 342 N.L.R.B. 977 (2004), it was

not enough for the NLRB simply to follow suit without an 

explanation for why it, too, was leaving behind settled 

precedent.

B

The NLRB claims that “the NMB has primary authority to 

interpret the RLA,” Oral Arg. Tr. 30:6-7, and readily 

acknowledges that its practice is “to apply the NMB’s test,” id.

at 26:22-23. Indeed, the NLRB has for years hitched its wagon 

to the NMB’s star, including in formal, published opinions. 

See, e.g., Aircraft Serv. Int’l Grp., 342 N.L.R.B. at 977. When 

the NLRB first adopted and applied the NMB’s traditional test, 

it bound itself to continue doing so; any deviation would 

require a reasoned explanation. In finding that it had 

jurisdiction over the Company, however, the NLRB relied 

exclusively on the NMB’s most recent precedent—silently
17

elevating the airlines’ power over personnel decisions to 

dispositive status.

It is well-settled that the NLRB—like any other agency—

cannot “turn[] its back on its own precedent and policy without 

reasoned explanation.” Dupuy v. NLRB, 806 F.3d 556, 563 

(D.C. Cir. 2015); see also E.I. Du Pont de Nemours & Co. v. 

NLRB, 682 F.3d 65, 70 (D.C. Cir. 2012) (explaining that the 

NLRB must “give a reasoned justification for departing from 

its precedent”). Generally speaking, “the requirement that an 

agency provide reasoned explanation for its action . . .

demand[s] that it display awareness that it is changing position. 

An agency may not, for example, depart from a prior policy sub 

silentio or simply disregard rules that are still on the books.” 

FCC v. Fox Television Stations, Inc., 556 U.S. 502, 515 (2009). 

And if “a party makes a significant showing that analogous 

cases have been decided differently, the agency must do more 

than simply ignore that argument.” LeMoyne-Owen Coll. v. 

NLRB, 357 F.3d 55, 61 (D.C. Cir. 2004). Thus, when the Board 

fails to explain—or even acknowledge—its deviation from 

established precedent, “its decision will be vacated as arbitrary 

and capricious.” Manhattan Ctr. Studios, Inc., v. NLRB, 452 

F.3d 813, 816 (D.C. Cir. 2006).

Because the NLRB follows the NMB’s lead in interpreting 

and applying the RLA, the question becomes how to treat an 

unacknowledged and unexplained deviation from precedent by 

the NLRB that is precipitated by a likewise unacknowledged 

and unexplained deviation from precedent by the NMB. We 

hold that, under such circumstances, the NLRB is not free to 

simply adopt the NMB’s new approach without offering a 

reasoned explanation for that shift. Indeed, an agency cannot 

avoid its duty to explain a departure from its own precedent 

simply by pointing to another agency’s unexplained departure 

from precedent. This is a corollary of the rule that an agency 
18

cannot justify a departure from its precedentsimply by pointing

to another one of its cases that departed from precedent, if that 

other case does not itself announce the new standard or a

supporting rationale for it. See Ramaprakash v. FAA, 346 F.3d 

1121, 1128-29 (D.C. Cir. 2003) (citing Hatch v. FERC, 654 

F.2d 825, 834 (D.C. Cir. 1981)). 

In short, the NLRB should have recognized that 

longstanding NMB precedent—which the NLRB previously 

followed—compelled a finding of control in this case. The

NLRB may have fairly read recent NMB opinions to require

greater carrier control over personnel matters than the record 

evinced here. But rather than ignore the NMB’s earlier 

precedent, which it had effectively adopted as its own, the 

NLRB was obligated to consider that precedent and 

acknowledge the conflict in this case. See Hatch, 654 F.2d at 

834-35 (requiring “explicit recognition by [an agency] that the 

standard has been changed” and a genuine “attempt to 

forthrightly distinguish or outrightly reject apparently 

inconsistent precedent”). At that point, the NLRB would have 

had two options. First, it could have attempted to offer its own

reasoned explanation for effectively whittling down the 

traditional six-factor test. It would have needed to explain why 

such a change was appropriate, how the new test reasonably 

interprets the RLA, and why the NLRB has decided to 

determine for itself the appropriate test rather than keeping 

with its past practice of referring such questions to the NMB

and deferring to their formulation of the test for RLA 

jurisdiction. Or the NLRB could have simply referred this 

matter to the NMB and asked that agency to explain its decision 

to change course. If the NLRB were persuaded, it could then 

have adopted the NMB’s explanation as its own. The NLRB, 

however, followed neither path. As a result, we must vacate the 

NLRB’s order as arbitrary and capricious. 
19

At oral argument, counsel for the NLRB was asked what 

the appropriate remedy would be if the Board had in fact 

applied a new test without explanation. Counsel suggested that, 

on remand, it would be up to the NLRB to provide some 

explanation justifying the new test or to identify another 

agency that could. See Oral Arg. Tr. 24:1-6. We agree. Either 

scenario is preferable to the present state of affairs, in which 

both employers and employees are caught in a web of 

conflicting precedent on the issue of RLA jurisdiction.

III

We grant the Company’s petition for review and deny the 

NLRB’s cross-application for enforcement. We vacate the 

NLRB’s order and remand for further proceedings consistent 

with this opinion.

So ordered.