270 F.3d 959 (D.C. Cir. 2001)
AT&T Wireless Services, Inc., et al., Appellantsv.Federal Communications Commission, AppelleeNortheast Communications of Wisconsin, Inc., d/b/a Cellcom, Intervenors
No. 00-1304
United States Court of Appeals  FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued October 1, 2001Decided November 9, 2001

Appeal from an Order of the Federal Communications Commission
L. Andrew Tollin argued the cause for appellants.  With  him on the briefs were Michael Deuel Sullivan, Douglas I.  Brandon, Carol L. Tacker and John T. Scott III.
Roberta L. Cook, Counsel, Federal Communications Commission, argued the cause for appellee.  With her on the brief  was Daniel M. Armstrong, Associate General Counsel.
Ronald J. Wiltsie II argued the cause for intervenors. With him on the brief were Michele C. Farquhar, Ronnie  London, Donald J. Evans, Timothy Edward Welch, Russell  D. Lukas and David L. Nace.  David G. Leitch entered an appearance.
Before:  Edwards, Rogers and Tatel, Circuit Judges.
Opinion for the Court filed by Circuit Judge Rogers.
Rogers, Circuit Judge:


1
In the order on review, the Federal  Communications Commission affirmed orders by the Bureau  of Wireless Telecommunications granting a waiver of 47  C.F.R.22.925 for two years to permit AirCell, Inc. and  cellular licensees that had entered into resale agreements  with AirCell to provide airborne cellular telephone service. See AirCell, Inc., 15 F.C.C. Rcd. 9622 (2000).  Petitioners  AT&T Wireless Services, Inc., Bell South Cellular Corp., SBC  Wireless, Inc., and Cellco Partnership seek review of the  Commission's order on three principal grounds.1  First, they  contend that the Commission violated its rules as well as the  licensing scheme of the 1934 Communications Act by granting  a waiver that modifies the licenses of existing licensees, and  by failing to require AirCell to apply for a license to provide a  new nationwide air-ground radio communications service. Second, they contend that the waiver was arbitrary and  capricious insofar as it eviscerates the rule, contravenes Commission precedent, and violates Commission policy to proceed  by rulemaking when changing rules affecting a broad segment of industry.  Third, they contend that the Commission  failed to provide a reasoned explanation for its conclusion that  harmful interference was not likely to result from the AirCell  system.  We grant the petitions in part, remanding the case  to the Commission for further explanation of one aspect of its  waiver decision;  otherwise we deny the petitions.

I.

2
Section 22.925 of the Commission's rules provides, in pertinent part:


3
Cellular telephones installed in or carried aboard airplanes, balloons or any other type of aircraft must not be operated while such aircraft are airborne (not touching the ground).  When any aircraft leaves the ground, all cellular telephones on board that aircraft must be turned off.


4
47 C.F.R.22.925 (2000).  Under 1.3, the Commission has  authority to waive its rules "if good cause therefor is shown." Id.1.3.


5
AirCell, Inc. began developing and testing a low-power  cellular system installed on general aviation aircraft under a  Special Temporary Authority from the Commission in 1992. Two years later, the Commission's Office of Engineering  Technology authorized AirCell to operate as an experimental  radio station, providing service on a secondary basis.  Pursuant to 47 C.F.R.2.104(d)(3)(i) and (ii), stations with secondary status "[s]hall not cause harmful interference to stations  of primary services to which frequencies are already assigned  or may be assigned at later date," and "[c]annot claim protection from harmful interference" from such primary stations.


6
The AirCell system consists of specially engineered handsets, ground stations, and so-called "smart" aircraft antennae  designed to provide low-power airborne cellular communications without creating harmful interference for other cellular  networks.  AirCell's ground stations are co-located in rural  areas at the cell sites of participating cellular licensees, and  customer traffic from the airborne mobile units is interconnected with the public switched network through the switches  of AirCell's participating licensees.  In addition to hardware  and software modifications designed to provide cellular communications at relatively low power levels, the AirCell system  seeks to minimize the potentialfor harmful interference  through the use of horizontal polarization, specially shaped  antenna patterns, non-standard control channels, and frequency coordination with non-participating cellular providers. The AirCell system was tested by AirCell and petitioners on  July 10 and 11, 1997, using four sites in Texas and Oklahoma,  and again by petitioners on September 22, 1998, in Florida.


7
On October 9, 1997, AirCell filed a petition requesting that  the Commission waive, among other things,22.925 of its  rules to permit commercial deployment of AirCell service. Ten months later, AirCell and a number of cellular licensees  entering into resale agreements with AirCell filed an amended petition to join the waiver request, thereby establishing  that the participating licensees had agreed to modifications of  their existing cellular licenses to authorize this secondary use  of their licensed spectrum.  The Bureau of Wireless Telecommunications ("Bureau") conditionally granted the waiver requests on December 24, 1998.  Determining that the AirCell  system's potential for interference should be evaluated according to its performance under normal operating conditions,  the Bureau found that "the record fully supports the conclusion that because of the lower power, special antennas, and  other features unique to the AirCell mobile unit, the risk of  harmful interference that use of an ordinary cellular telephone[ ] in an airborne aircraft poses has been addressed."  Consequently, in the Bureau's view, the harm  that22.925 is intended to prevent "will most likely not  occur," and special circumstances justified a waiver of the  general rule.  The Bureau concluded a waiver was also  warranted because the public safety benefits to aircraft that  will accrue from the use of the AirCell system serve the  public interest.  Further, the Bureau observed, AirCell's  voice and data link promotes competition by providing small  aircraft and general aviation consumers an alternative to  existing air-ground services.


8
The Bureau imposed nine special conditions on the waiver,  including the requirement that cellular service to airborne  terminals be a secondary service, and that participating licensees provide at least thirty days prior notice of service or  testing to co-block licensees with transmitter sites within 270  kilometers of their ground stations.  The Bureau's conditions  further stipulated that participating licensees had a duty to provide information promptly on request of the Commission  regarding any complaint of interference, and an obligation to  resolve any instance of harmful interference, which was defined as "serious degradation, obstruction, or repeated interruption of cellular service."


9
On three occasions, the Bureau conditionally granted waivers for additional licensees.  In so doing, the Bureau rejected  the opposing carriers' arguments that, among other things,  AirCell had taken over obligations of the participating licensees and failed to provide proper advance notice to opposing  carriers.  On reconsideration the Bureau also clarified several  waiver conditions and reduced the notification distance from  270 to 151 kilometers, noting that during the Texas Oklahoma tests the airborne received signal "was not strong  enough to interfere with terrestrial cellular communications,  except when the AirCell power control system was deliberately disabled for testing purposes."


10
The Commission largely affirmed the Bureau's orders  granting conditional waivers and reset the two-year term of  the waivers to begin on June 9, 2000, the effective date of its  order.  The Commission "agree[d] with the Bureau's technical assessment of the AirCell system, including its judgment  that there is little risk the system will cause harmful interference to non-participating carriers, as well as its evaluation of  the system's potential benefit for general aviation."  AirCell,  15 F.C.C. Rcd. at 9627.  Based primarily on the design  characteristics of the AirCell system and the results of the  first day of the Texas-Oklahoma field tests on July 10 and 11,  1997, the Commission concluded that AirCell had carried its  burden of affirmatively showing that its system is not likely  to cause harmful interference to terrestrial cellular operations.  The Commission noted that for the July 10, 1997, test,


11
AirCell chose a "worst case" scenario for site location, i.e., the tests were conducted in a rural area where there was no urban noise to mask the AirCell signal, and in a manner such that the AirCell airborne mobile unit was close to the "victim" site and far from the AirCell partner site.  With this configuration, the AirCell mobile has to  emit its highest power level in order to reach its partner site.  Even under this configuration, the data from the first day of testing show that there is little likelihood of harmful interference.


12
Id. at 9630 n.60.  The Commission rejected as unpersuasive  the evidence presented by the opposing carriers and rejected  the opposing carriers' remaining arguments that, for example,  the AirCell system violated their exclusive channel block  assignments under 47 C.F.R.22.905(a), and that their  licenses were improperly modified by the AirCell order.  By  relegating the AirCell system to secondary status in the  cellular band and requiring advance notification to help ensure that all primary cellular service is protected from harmful interference throughout the waiver term, the Bureau had,  in the Commission's view, provided nonparticipating licensees  with "adequate, indeed redundant, interference protection." Id. at 9629.  At the same time, the Commission disclaimed  any reliance on a probability study submitted by AirCell. The Commission added several other technical operating  conditions "to ensure that the AirCell system will in fact  operate within the technical parameters on which the Bureau's decision was based."  Id. at 9627.

II.

13
Petitioners raise a variety of objections to the Commission's order.  We address in Part A whether the Commission  violated its rules and the licensing scheme of the Communications Act by allowing AirCell to provide a new nationwide  radio communications service without a license.  In Part B,  we address whether the waiver grant was arbitrary and  capricious.  In Part C, we address whether the Commission  failed to provide a rational explanation for its conclusion that  harmful interference was not likely to result from the AirCell  system.


14
Under our standard of review, the court must uphold the  Commission's order unless it is "arbitrary, capricious, an  abuse of discretion, or contrary to law."  5 U.S.C. 706(2)(A).  See also Greater Boston Television Corp. v.  FCC, 444 F.2d 841, 851 (D.C. Cir. 1970).

A.

15
Contending that the Commission "effectively granted the  [license] application that AirCell could not file" consistent  with Commission rules, petitioners maintain that the Commission also "effectively modified all cellular carriers' licenses  nationwide without complying with Section 316 of the Communications Act, 47 U.S.C.316."  There is no merit to  these contentions.


16
The two relevant rules relate to geographic exclusivity and  protection from interference.  The first, 47 C.F.R. 22.905(a), provides:  "Each channel block is assigned exclusively to one licensee for use in that licensee's cellular geographicservice area ("CGSA") (see 22.911)."  The second,  47 C.F.R.22.911(d), provides in relevant part:  "Within the  CGSA determined in accordance with this section, cellular  systems are entitled to protection from co-channel and firstadjacent channel interference and from capture of subscriber  traffic by adjacent systems on the same channel block."  The  Commission's interpretations of its rules regarding the rights  of cellular licensees, including the right to channel block  exclusivity and freedom from interference or signal capture  within a given CGSA, are entitled to substantial deference. See Thomas Jefferson Univ. v. Shalala, 512 U.S. 504, 512  (1994);  Trinity Broad. of Florida, Inc. v. FCC, 211 F.3d 618,  625 (D.C. Cir. 2000).  The court therefore will accept that  these rules proscribe only harmful interference within a given  carrier's CGSA, which we address in Part II C, infra.  Absent harmful interference, AirCell's new system does not  trammel upon petitioners' rights as licensees.  See AMSC  Subsidiary Corp. v. FCC, 216 F.3d 1154, 1158-59 (D.C. Cir.  2000).  Put otherwise, the waiver does not mean that the  licensees participating with AirCell may provide airborne  cellular service in a manner that would conflict with the  regulatory protections afforded to nonparticipating carriers  under their existing licenses.  The Commission emphasized  the importance of AirCell's secondary status and advance  notification to nonparticipating carriers so that they can steer  AirCell away from use of particular channels.  As the Commission explained, with the grant of the waivers nothing  changed insofar as the protections to which existing licensees  are entitled.


17
There is likewise no merit to petitioners' contention that  AirCell was required to be licensed.  See 47 U.S.C. §§ 301,  304, 307-310 (1991 & Supp. 2001).  So long as the licensees in  partnership with AirCell maintain actual control over the  transmission equipment used in AirCell's system and continue  to abide by their own regulatory obligations, the court has no  basis for second-guessing the Commission's description of  AirCell as a "reseller."  Contrary to petitioners' contention,  the Commission expressly rejected the claim that an unauthorized transfer of control of the licensees' operations to AirCell  had occurred.  The Commission stated that "[i]n the case of a  nationwide network such as AirCell is attempting to build,  ... the AirCell partners, while remaining responsible for  complying with Commission requirements ... may reasonably and prudently assign a single entity the task of being a  central contact point for system management and system/site  termination purposes."  Aircell, 15 F.C.C. Rcd. at 9643.


18
Nor did the Commission contravene its precedent in characterizing AirCell's relationship to its participating carriers as  a resale.  See Resale and Shared Use, Docket 20097, Report  and Order, 60 F.C.C.2d 261, 263 (1976), recon., 62 F.C.C.2d  588 (1977), aff'd sub nom. AT&T v. FCC, 572 F.2d 17 (2d  Cir.), cert. denied, 439 U.S. 875 (1978).  As the Bureau  explained in rejecting the argument that AirCell is a facilitiesbased service provider seeking co-primary status with nonparticipating cellular licensees, "AirCell holds no cellular license of its own, but instead purchases capacity to support  the AirCell service from participating cellular licensees pursuant to resale agreements."  AirCell's partners have agreed to  modifications of their licenses to permit this secondary use of  their licensed spectrum.  An analogous situation existed with  regard to the credit card facilitator of railroad cellular service  in GTE Airfone, GTE Railfone, and GTE Mobilnet, 8 F.C.C.  Rcd. 6171 (Aug. 27, 1993).


19
For these reasons, the court affirms the Commission's  determination that the only legal obstacle to the launch of  AirCell's system was the bar in 22.925.

B.

20
Petitioners' challenges to the Commission's waiver of 22.925 as arbitrary and capricious are also meritless.


21
In WAIT Radio v. FCC, 418 F.2d 1153 (D.C. Cir. 1969), the  court explained that the "agency's discretion to proceed in  difficult areas through general rules is intimately linked to  the existence of a safety valve procedure for consideration of  an application for exemption based on special circumstances." Id. at 1157.  Waiver is thus appropriate when "particular  facts would make strict compliance inconsistent with the  public interest."  Northeast Cellular Tel. Co. v. FCC, 897  F.2d 1164, 1166 (D.C. Cir. 1990).  Given the Commission's  findings about the unique capability of the AirCell system to  provide low power non-degrading cellular service and its  contributions to the public interest, petitioners' challenge to  the Commission's decision to act by waiver rather than by  rulemaking is unpersuasive.


22
The Commission's concern has been with the serious risk of  harmful interference to terrestrial systems from the greatly  enhanced transmitting range of ordinary cellular telephones  used aboard airborne aircraft.  See Airborne Use of Cellular  Telephones, 7 F.C.C. Rcd. 23 (Dec. 30, 1991).  AirCell represented to the Commission that most conventional cellular  systems are optimized for vertical wave polarization;  as a  result, horizontally polarized signals used by the AirCell  system are less prone to capture by terrestrial receiving  antennas.  The Commission noted that "smart" antennae  mounted on AirCell-equipped aircraft are designed to transmit specially shaped patterns that reduce the risk of interference.  Because the Commission reasonably interpreted 22.925 as being intended to protect against only harmful  interference from airborne cellular telephone use, petitioners'  contention that the waiver "eviscerates" the purpose of 22.925 necessarily fails.  Cf. Busse Broad. Co. v. FCC, 87  F.3d 1456, 1463-64 (D.C. Cir. 1996).  The Commission could  reasonably conclude that when combined with the use of nonstandard control channels and frequency coordination with  nonparticipating licensees, the collective effect of AirCell's low-power technological design serves to minimize the risk  that its operations will degrade the signals of other cellular  service providers, thereby addressing the concerns underlying the rule.


23
In identifying the public interest, see Keller Communications, Inc. v. FCC, 130 F.3d 1073, 1076 (D.C. Cir. 1997), the  Commission found "few viable alternatives that may provide  'safety-related voice communications between pilots and  emergency personnel, and can be used to uplink in-cockpit,  up-to-the-minute-weather and air traffic information as well  as potentially provide in-flight monitoring of airframe and  engine operations, serving to better inform ground personnel  of aircraft operations.' "  AirCell, 15 F.C.C. Rcd. at 9644. The Commission's determination is owed considerable deference.  See Metro. Council of NAACP Branches v. FCC, 46  F.3d 1154, 1164 (D.C. Cir. 1995);  Health and Med. Policy  Research Group v. FCC, 807 F.2d 1038, 1043 (D.C. Cir. 1987). The record before the Bureau included supportive statements  by the National Transportation Safety Board, the Federal  Aviation Administration ("FAA"), and the National Association of State Aviation Officials.  Although the FAA did not  certify the AirCell system as dedicated public safety equipment, the Commission observed that theFAA noted several  public benefits that could be derived from the system, and  that on balance, in view of the protections for primary cellular  service, these benefits justified granting the waiver.  The  Commission's conclusion that the waiver will offer significant  public safety benefits is thus amply supported by the record.


24
Petitioners' remaining challenges need only brief response.  First, contrary to petitioners' contention that the "me-too"  waiver process unlawfully delegates authority to private parties by allowing AirCell to arbitrarily exempt any carrier of  its choice from the rule with no individualized showing, nothing in the order indicates that the Commission granted  AirCell exclusive authority to provide nationwide airborne  cellular service.  The waiver is limited to two years, and the  order does not state that a similar service provider could not  also obtain a waiver.


25
Second, because the opposing carriers did not seek clarification on reconsideration, see 47 U.S.C.405, that the waiver  did not apply to commercial aircraft, the Commission's decision and order can hardly be faulted for failing specifically to  address commercial aircraft.


26
Third, petitioners cannot now contend that the protection  provided by the secondary status of AirCell's operation is  "illusory" should interference occur because tracing interference to AirCell operations is "infeasible" and recourse to the  complaint process will be ineffective.  The opposing carriers'  application for review of the Bureau's waiver orders did not  challenge the feasibility of initiating an interference complaint, and hence the Commission was not afforded a fair  opportunity to pass on the issue.  See Bartholdi Cable Co. v.  FCC, 114 F.3d 274, 279-80 (D.C. Cir. 1997) (citing 47 U.S.C. 405(a)(2));  see also 47 C.F.R.1.115(b).  The Commission's decision was adopted on May 24, 2000, and petitioners  do not dispute that the ex parte letters on which they rely,  dated April 4, 2000, and June 5, 2000, were untimely.  The  brief reference in petitioners' September 24, 1999, reply (to  AirCell's opposition to review of the Bureau's reconsideration  order) to problems documenting overflights of brief duration  concerned whether the Bureau erred in allowing AirCell  operations on DCMA guardband channels, and thus cannot  fairly be said to have alerted the Commission to a different  issue, namely, the feasibility of enforcing AirCell's status as a  secondary service.  See, e.g., Alianza Federal de Mercedes v.  FCC, 539 F.2d 732, 739 (D.C. Cir. 1976).

C.

27
Although petitioners raise a host of claims in contending  that the Commission had no basis for its determination that it  was not likely that AirCell's operations would cause harmful  interference to terrestrial cellular systems, the court's concern is confined to one aspect of the Commission's explanation.


28
The parties agree that for terrestrial cellular service to  remain effective, the signal from a terrestrial cell phone must sufficiently exceed the electromagnetic noise floor of the  location where the call is received, plus whatever interference  may be generated by a concurrent AirCell signal (i.e., the socalled "signal-to-noise-plus-interference ratio").  AirCell  claims, and petitioners do not appear to dispute, that the  industry standard for this ratio is 17dB.  Conversely, and as  a corollary principle, interference from an AirCell signal that  falls within the existing noise floor should not be detectable to  a terrestrial cell phone user, much less degrade a terrestrial  signal utilizing the same frequency within the same CGSA. Apart from this baseline understanding, however, the evidence before the Commission on the levels of harmful interference that AirCell's system could cause was in conflict.


29
On the one hand, AirCell submitted reports indicating that  there was virtually no chance that its service would cause  harmful interference to terrestrial cellular operations.  A  report prepared by AirCell consultants, TEC Cellular, Inc.  ("TECC"), found that virtually all interference from AirCell  signals in urban, suburban, and rural areas fell within the  existing noise floors of those environments during normal  operations.  Relying largely on measured signal strength  data from the July 10, 1997, test runs, which were designed to  simulate "normal" operating conditions (i.e., with all AirCell  components operational and airplanes flying point-to-point  paths), the TECC report concluded that "[f]ull scale AirCell  operation, properly deployed and engineered, will cause a  level of interference to terrestrial calls so low that while it  may be detectable with sensitive test equipment, it should be  imperceptible to terrestrial callers."  In addition, AirCell  submitted a report incorporating the results of a probability  study, based also on the July 10, 1997, test data, which  concluded that there was only a five-in-a-million chance that  an AirCell call could noticeably degrade a terrestrial call.


30
On the other hand, the opposing carriers submitted contrary analyses of the test data.  For example, an engineering  report submitted by Dr. William C. Y. Lee, Vice President  and Chief Scientist, and Mark Schulz, Technology Director of  the Strategic Technology Group of AirTouch Communications, Inc., concluded, based on the July 10 and 11, 1997, test  data, that harmful interference was likely to occur 30% of the  time.  They based this conclusion on the assumption that the  test runs employed on both days are equally probable to  occur during actual operations, and that a minus 124 dBm  interference threshold should be employed in calculating the  likelihood of harmful interference, rather than the minus 117  dBm threshold used for acceptable voice quality in the interference assessment submitted by AirCell, or the minus 110  dBm threshold used in the TECC report as a reasonable  lower limit on an acceptable ground call.  In addition, Dr. Lee  and Mr. Schulz claimed that there was no test data below the  5000' altitude level, notwithstanding a "disturbing trend"  showing higher interference levels at progressively lower  altitudes, and that there was no mechanism in the AirCell  system to terminate and block calls below 5000'.


31
The Commission adequately explained why it rejected the  July 11, 1997, Texas-Oklahoma test data and the September  22, 1998, Florida test data upon which petitioners rely.  The  July 11, 1997, test runs were conducted without the dynamic  power control element, which eliminated the benefits of one of  the main components of the AirCell design.  In addition, the  flight patterns employed on that date were abnormal, such  that the Commission concluded that they simulated conditions  approximating a "major malfunction."  AirCell, 15 F.C.C.  Rcd. at 1630.  For similar reasons, the Commission discarded  the Florida test results, which also involved abnormal flight  patterns around a "victim" cell site at close range and low  altitude.  The Commission further noted that the opposing  carriers had installed the wrong type of antenna during the  Florida test, did not record the AirCell mobile transmitter  power output, and deliberately matched the supervisory audio  tone to prevent the AirCell telephone from hanging up once it  had lost a usable signal from the AirCell ground station.  In  addition, given its view that the results of the second day of  the Texas-Oklahoma tests and the Florida tests were unreliable, the Commission sufficiently justified its rejection of the  opinions of the chief operating officers of six major cellular  carriers for lack of crediblesupporting evidence.  Finally, the Commission reasonably explained that concern about interference from uptilted antennas was adequately addressed by the  ordinary coordinating process that every cellular licensee  must conduct under Commission rules.


32
However, in rejecting the report of Dr. Lee and Mr. Schulz,  the Commission provided no such clarity as to its choice of  the appropriate interference threshold.  Rather, the Commission simply stated that they had relied on "unrealistic assumptions, including the use of an unrealistically low interference threshold."  Id. at 9631.  In the Commission's view, use  of a threshold of minus 124dBm was "too conservative and  ... an interference threshold of minus 117 dBm is more  realistic for typical analog systems."  Id. at 9631 n.67.  This  may be so, and the court would otherwise defer to the  Commission's expertise.  See Keller Communications, 130  F.3d at 1078.  But the Commission's succinct statement fails  to provide a reasoned justification for rejecting the minus 124  dBm threshold, much less a defense of the minus 117 dBm  threshold that the Commission viewed as being "more realistic."  Nor does the Commission indicate that it was relying on  any rules or standards regarding such determinations.  The  omission of an explanation of its choice of an interference  threshold is particularly troubling because the July 10, 1997,  test data, which was the only test data on which the Commission apparently relied, did not represent the full range of  operational conditions in which AirCell's phones are likely to  be used.


33
The only other clarification that the Commission provided  was a conclusory assessment, again without further explication, that "[b]ased on our review of the evidence, it appears to  us that use of the latter [minus 117 dBm] threshold would  have led to a finding that AirCell would cause a significant  level of harmful interference 0% of the time."  Id.  Obviously,  this does not fill the void.  Nor, of course, can the fact that  AirCell used the minus 117 dBm threshold in its own report  suffice to explain the Commission's choice.  That petitioners  may not dispute the results of applying different dBm thresholds to the test data likewise does not fill in the gap, as the  Commission appears to suggest in its brief.  The Commission's failure to justify adequately its choice of an interference  threshold thus implicates its additional failure to explain how  it was able, in the absence of a probability study, to translate  the raw signal data from the July 10, 1997, field test into a  finding that AirCell's system "would cause a significant level  of harmful interference 0% of the time" in the real world.


34
Conclusory explanations for matters involving a central  factual dispute where there is considerable evidence in conflict do not suffice to meet the deferential standards of our  review.  Basic principles of administrative law require the  agency to " 'examine the relevant data and articulate a satisfactory explanation for its action including a rational connection between the facts found and the choice made.' "  U.S.  Telecom Ass'n v. FCC, 227 F.3d 450, 461 (D.C. Cir. 2000)  (quoting Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto.  Ins. Co., 463 U.S. 29, 43 (1983)).  The Commission may well  be able, based on the record that was before it, to resolve  satisfactorily the issue of harmful interference in AirCell's  favor.  Indeed, the explanation for its conclusion in AirCell's  favor may be relatively simple and briefly stated.  Because  there is too much evidence in the record suggesting a contrary conclusion, however, the court is unable to discern why  the Commission considered one interference threshold preferable to another or how it could extrapolate from the July 10,  1997, test data in the absence of a probability study.  Accordingly, we grant the petitions in part.



Notes:


1
  See 47 U.S.C.402(a) (1991);  Capital Cities Communications, Inc. v. FCC, 554 F.2d 1135, 1136 n.1 (D.C. Cir. 1976).


