GOLDBERG. Circuit Judge:

We embark on a journey into the lofty area of aviation safety regulation. Previous navigators have left powerful beacons along the way to guide us. The law in this area is not too far up in the air. We may encounter a few clouds of doubt, but they will dissipate. We anticipate a smooth flight before descending to our final destination.

Roger E. Woolsey appeals an order of the National Transportation Safety Board ("NTSB") which affirmed the FAA's revocation of his commercial pilot's certification due to his failure to comply with the safety requirements for pilots operating aircraft for a common carrier under Part 135 of the Federal Aviation Regulations ("FAR), 14 C.F.R. § 135. Neither the Federal Aviation Act of 1958, 49 U.S.C.App. § 1301 et seq., nor the regulations promulgated thereunder, define the term "common carrier." Woolsey disputes the definition used by the FAA and the NTSB. He claims that the aircraft he piloted were not operated in common carriage, and hence that the less stringent safety requirements of FAR Part 91 should have been applied by NTSB. He also contends that the NTSB erred in affirming the administrative law judge's admission into evidence of certain documents pertaining to the marketing efforts of Prestige Touring, Inc. ("PTI"). We find that the NTSB's interpretation of the term "common carrier" as applied to air carriers was correct, and that the fact finding of the NTSB was supported by substantial evidence even without reference to the documents Mr. Woolsey sought to have excluded.

Roger E. Woolsey is president of Prestige Touring, Inc. ("PTI"), a small air carrier which specializes in transporting musicians. Prior to entering into an agreement to transport the country musician Reba McEntire for a minimum of several hundred hours per year, PTI marketed itself primarily to rock musicians, with whom it had at least twenty-five contracts in 1990. Although Woolsey claims that PTI makes "individualized decisions in particular cases whether and on what terms to serve . . . [and] does not furnish transportation indiscriminately, but furnishes it only to those with whom it sees fit to contract," there is no evidence that PTI ever turned away anyone in the music industry who applied to it for air transportation and was willing to pay its fee.

Woolsey became aware in the late 1980s of the fact that most country musicians travel by bus, and he determined to take advantage of that largely untapped market. In 1989, Woolsey sent Reba McEntire's manager (who is also her husband) information about the services offered by PTI. Although PTI engaged in self-promotion in a major periodical read by many in the music industry, Woolsey considered it important to make direct contact with stars like McEntire in order to expand from "rock" into the country music segment of the music industry.

Shortly after the "press kit" sent by PTI to McEntire's manager arrived, an agreement was negotiated by Reba's Business, Inc. ("Reba's Business") and PTI, whereby PTI agreed to transport McEntire and her entourage for a fee for a minimum number of hours of flight time per year. An additional standard hourly fee was to be levied for any flight time over and above the minimum hours specified in the contract. PTI agreed to provide a specific aircraft for the exclusive use of McEntire and her guests. PTI painted Reba McEntire's name and that of her son, Shelby Blackstock, on the fuselage of the airplane. McEntire and her guests were permitted to leave their personal belongings on the plane at all times. PTI agreed to McEntire's request that flights be made from the airport in Gallatin, Tennessee, which was more conveniently located for McEntire than the Nashville airport at which PTI originally intended to provide her with service. PTI rented an apartment in the Gallatin, Tennessee area, in order that a flight crew would be available to transport Ms. McEntire on short notice.

Woolsey claims that all of the "lease agreements" between PTI and Reba's Business were intentionally designed so as to comport with the requirements of FAR Part 91, not FAR Part 135. He contends that these leases constituted "time sharing agreements," which are governed under FAR Part 91 if they involve private or contract carriers. Thus, whether or not the leases comport with the requirements of FAR Part 91, the crucial question remains whether PTI acted as a common carrier with respect to the flights in question.

When another PTI airplane for which Reba's Business had contracted crashed, Reba's Business ceased doing business with PTI. On July 5, 1991, a Federal Aviation Administration ("FAA") Administrator issued an emergency order revoking Woolsey's commercial pilot certificate due to his alleged violation of Section 91.13(a) of the Federal Aviation Regulations, 14 C.F.R. § 91.13(a). Woolsey was alleged to have served as pilot in command on fifty-three flights for compensation without meeting the training and examination requirements of FAR Part 135. He was also alleged to have intentionally stopped an engine during one flight in order to avoid having to stop for fuel.

On July 24, 1991, after an evidentiary hearing, an administrative law judge orally affirmed the FAA Administrator's decision. Petitioner appealed to the National Transportation Safety Board, which on Aug. 28, 1991, issued an opinion affirming the administrative law judge's decision with respect to the revocation of Woolsey's license. The NTSB refused to affirm the administrative law judge's finding that the intentional engine stoppage constituted careless or reckless endangerment of the life or property of others, nevertheless concluded that "the sanction of revocation is clearly appropriate where, as here, respondent operated as pilot in command of fifty-three flights with paying passengers, to whom he owed a high standard of care, and when he did not have the necessary training, examinations and check rides required of him under Part 135 [which applies to common carriers]." The NTSB based its finding that PTI was a common carrier on the definition of that term provided in FAA Advisory Circular No. 120-12A.

Woolsey appealed the NTSB decision to this court pursuant to 49 U.S.C.App. § 1486(a). PTI is not a party in the instant case. First, we must decide whether the NTSB erred in affirming the administrative law judge's admission of certain evidence which was offered to support the Federal Aviation Administration's argument that PTI held itself out to the public as a common carrier. Second, in considering whether the comparatively stringent safety regulations of Part 135 apply (as opposed to those of Part 91), we must decide whether the flights in question were operated by Woolsey in "common carriage," a term that the Federal Aviation Regulations leave undefined.

DISCUSSION [11] I. THE ADMINISTRATIVE LAW JUDGE'S ADMISSION OF EVIDENCE OF PTI'S MARKETING EFFORTS

Woolsey claims that the NTSB erred in affirming the administrative law judge's admission into evidence of Exhibits A-9 through A-15, which were offered by the FAA to show that PTI had held itself out to the public. Woolsey contends that these exhibits should not have been admitted because they were not authenticated by any witness with personal knowledge of them. He further contends that the failure to authenticate the documents by presenting their authors or signatories as witnesses deprived him of the right to confront and cross-examine witnesses against him.

The NTSB has not adopted rules of evidence. In 1986, the Administrative Conference of the United States adopted recommendations which stated that it would be improper to require agencies to apply the Federal Rules of Evidence. Recommendation 86-2, 1 C.F.R. § 305.86-2. The only Federal Rule of Evidence strongly recommended by the Conference for use in agency proceedings was Fed.R.Evid. 403 ("Exclusion of Relevant Evidence on Grounds of Prejudice, Confusion, or Waste of Time"). Section 556(d) of the Administrative Procedure Act, which applies to proceedings before the NTSB, only requires the exclusion of oral or documentary evidence which is irrelevant, immaterial, or unduly repetitious. 5 U.S.C. § 556(d). Sorenson v. National Transportation Safety Board, 684 F.2d 683, 686 (10th Cir. 1982). This standard is "somewhat lower" than that required for authentication of documents under Fed.R.Evid. 901, but nevertheless "does not completely obviate the necessity of proving by competent evidence that real evidence is what it purports to be. . . . [a]bsent any such proof, the evidence to be admitted would be irrelevant or immaterial and hence should be excluded from the proceeding." Gallagher v. National Transportation Safety Board, 953 F.2d 1214, 1218 (10th Cir. 1992) (emphasis added) (toxicological report held admissible in NTSB proceeding despite fact that chain of custody relating to body fluid sample "was somewhat compromised"; NTSB was not required to infer any deliberate acts of tampering or gross negligence in handling the evidence when none had been shown).

Although we note that a slightly lower standard for admission of documentary evidence applies in administrative proceedings than in the federal courts, we find that admission of the documents in question would have been proper under the Federal Rules. Woolsey contends that an FAA official's testimony that he had requested and received the documents during the course of his investigation was insufficient under Fed.R.Evid. 901(b)(1) to assure that the documents are authentic. He also claims that since neither the publishers nor the authors of the telephone books, periodicals, cancelled checks, letters, lease agreements and press kits testified, he was deprived of the right as "an accused" to confront and cross-examine witnesses against him. The FAA counters that there was no danger that the documents were not what they were claimed to be, and that Mr. Woolsey had every opportunity to cross-examine the FAA investigators who testified as to the method by which the documents were obtained and stored prior to the hearing. Mr. Woolsey did not claim that any of the documents allegedly signed by his employees contained forged signatures.

Exhibits A-9 and A-10, which consist of articles and self-promotional statements made by PTI in the weekly magazine Performance International, are self-authenticating documents under Fed.R.Evid. 902. While Woolsey appears to admit for the first time in his Reply Brief that the documents are self-authenticating, he attempts to maintain the claim that they should not have been admitted by arguing that they were irrelevant. Specifically, Woolsey claims that the self-promotional articles in Exhibits A-9 and A-10 pertained to service provided by PTI on a turboprop airplane, operation of which is governed by FAR Part 125, and not by FAR Part 91 or 135. We find this argument unpersuasive, because the exhibits do not specifically refer to any particular type of aircraft.

We find that there was no error in the admission of Exhibits A-11 through A-15. We believe there was adequate assurance of authenticity for documents A-11 through A-15 to be admitted. All of these documents pertain to solicitation of business by PTI. The documents were requested by, and sent to, FAA investigators, who were available to testify about the method in which the documents were obtained and kept by the FAA, and why it was reasonable to consider them authentic. There is no evidence that the signatures on the documents were forged or that the documents were otherwise falsified; nor is there any evidence that the documents, once received by the FAA investigators, ever left the investigators' hands. Fed.R.Evid. 901(a) provides that, "The requirement of authentication or identification as a condition precedent to admissibility is satisfied by evidence sufficient to support a finding that the matter in question is what its proponent claims." The Advisory Notes following Fed.R.Evid. 901 state that testimony of witnesses having "personal knowledge," broadly construed, can support the authenticity of a document. We do not believe that the admission of Exhibits A-11 through A-15 deprived Mr. Woolsey of "the accused's right to confront and cross-examine witnesses." All but one of the cases Mr. Woolsey cites in advancing his argument are criminal cases involving the Sixth Amendment. We consider those cases inapposite in this civil proceeding. See Administrator v. Harrison, 2 N.T.S.B. 504 (1973). The single civil case cited by Mr. Woolsey is Greene v. McElroy, 360 U.S. 474, 79 S.Ct. 1400, 3 L.Ed.2d 1377 (1959). That case involved an administrative proceeding in which a private individual working for a private company had his security clearance revoked by the Defense Department of the United States. The Supreme Court found that the failure to provide the employee any opportunity to confront the evidence against him or to cross-examine witnesses violated due process. In Greene, the government presented no witnesses and "[i]t was obvious . . . from the questions posed to petitioner and to his witnesses, that the [Industrial Employment Review Board] relied on confidential reports which were never made available to petitioner." 360 U.S. at 479, 79 S.Ct. at 1405. The petitioner in that case had no opportunity whatsoever to confront the evidence against him. In the instant case, by contrast, the FAA presented witnesses and documents which Woolsey was free to confront. Although he objected to the admission of the documents based on the absence of the persons who signed them, he did not claim the documents were forged or altered in any way. FAA investigators were available for cross-examination as to how they obtained the documents and why it would be reasonable to conclude that the documents were authentic.

Even if admission of any of the documents in Exhibits A-11 through A-15 was error, it was harmless. There was additional evidence on which the administrative law judge and the NTSB could have based the decision to affirm the FAA's revocation of Mr. Woolsey's commercial pilot certification. There was evidence presented that PTI actively solicited McEntire's business by sending her letters and brochures; engaged in self-promotion in periodicals available to the general public; publicly listed the names of scores of its clients in the music industry; and advertised in the yellow pages of the telephone book. We consider this to be "substantial evidence" supporting the view that PTI held itself out to the public as a common carrier.

II. DEFINITION OF "COMMON CARRIAGE" WITH RESPECT TO AIR CARRIERS; APPLICATION OF PART 135 IN THE INSTANT CASE

Woolsey contends that the contracts or "leases" for air transportation signed by himself and country music singer Reba McEntire were designed with an eye to compliance with the requirements of FAR Part 91. The Federal Aviation Administration ("FAA"), however, contends that the more stringent safety requirements of FAR Part 135 apply. The FAA admits that the flights in question in this case would be governed by Part 91 had PTI not advertised its services and actively solicited business. The FAA contends, however, that PTI held itself out to a definable segment of the general public as being available for air carriage for compensation, and that PTI was for that reason a "common carrier." FAR Part 91 specifically excludes common carriers from its coverage, leaving them subject to the more stringent safety standards of FAR Part 135. The policy behind this distinction appears to be that the general public has a right to expect that airlines which solicit their business operate under the most searching tests of safety. The term "common carrier" is not defined in the Federal Aviation Act or the Federal Aviation Regulations. Hence, we must look to other sources (the most important of which is the common law relating to air carriers) in order to determine whether PTI was a common carrier with respect to the flights in question in this case.

In response to potential confusion as to the meaning of the term "common carrier" under the Federal Aviation Act, the Federal Aviation Administration issued Advisory Circular No. 120-12A ("Advisory Circular") on April 24, 1986. The Advisory Circular provides FAA employees and members of the aviation industry with "general guidelines for determining whether current or proposed transportation operations by air constitute private or common carriage." Advisory Circular at 1. The Advisory Circular defines a common carrier as one which holds itself out to the public as being willing to transport persons or property for compensation, to the extent that its facilities permit.

Mr. Woolsey was aware of the definition of "common carriage" provided by the FAA in its Advisory Circular. However, Mr. Woolsey contends that PTI not only did not hold itself out to the public, but that the definition of common carriage contained in the Advisory Circular is too broad, does not have the force of law because it was not promulgated as a regulation under the Administrative Procedure Act, and is inconsistent with the common law definition of a common carrier. Woolsey claims that the common law defines a common carrier as one which (1) holds itself out to the public as willing to carry anyone who applies so long as there is room in the aircraft, (2) at a uniform price applicable to all who apply. He claims that PTI "furnished air transportation only to those with whom it saw fit to contract, as a private or contract carrier, and . . . any . . . "holding out" was no more than an invitation to negotiate such contracts on a case-by-case basis, without any evidence of uniformity of charges or willingness to carry all persons applying so long as there is room in the aircraft."

Instead of focussing on whether PTI held itself out to the public, Mr. Woolsey discusses at length the nature of PTI's contracts with Reba's Business; the fact that Ms. McEntire was given exclusive use of a PTI airplane; and the fact that the contract was not for a single or even several flights, but for a year's term. In so doing, he hopes to establish that the agreement at issue here was not a charter agreement, but a "time sharing" agreement under FAR Part 91; that the airplane known by air traffic controllers across the nation as "Reba Jet" was more like a private airplane than an airplane owned by a common carrier and chartered by a private party.

Woolsey notes that many of the cases defining "common carriage" as the FAA does are cases relating to economic regulation of air carriers, as opposed to safety regulation of air carriers. He contends that any relevance these cases might have had in the area of aviation safety was decimated in 1978 by Congress' abolition of the Civil Aeronautics Board and repeal of economic regulations affecting air carriers. Airline Deregulation Act of 1978, Pub.L. No. 95-504, Section 3; 92 Stat. 1705. We do not agree that these cases "have no precedential value after 1978," nor do we agree that the term "common carrier" as defined in economic regulation cases has no relevance in cases concerning safety regulation. The same definition has been applied in both economic and safety regulation cases. The term "common carrier," as used in the common law, was not affected by the repeal of certain economic regulations under the Airline Deregulation Act of 1978. The mere fact that one of the bodies responsible for developing the common law definition of common carriage no longer exists is no argument for abolishing the common law definition developed while that body was in existence.

We do not address the legal sufficiency of the Advisory Circular, for we find that the definition of common carrier provided therein is in relevant respect the same as that found at common law. Contrary to the assertion of Mr. Woolsey, the FAA does not seek to broaden the definition of common carriage. Mr. Woolsey seeks to narrow that definition in a manner inconsistent with the case law. He would have us hold that an air carrier engages in common carriage only when it transports all members of the public at the same price whenever it has room on its airplanes. Although there is some support for the view that a common carrier must deal on the same terms and conditions with all of its customers, see, e.g., Semon v. Royal Indemnity Co., 279 F.2d 737 (5th Cir. 1960) (charter of a fishing boat found to constitute private or contract carriage where there was no evidence of holding out), we are aware of no cases actually applying such a restrictive test to air carriers.

The Advisory Circular correctly points out that the crucial determination in assessing the status of a carrier is whether the carrier has held itself out to the public or to a definable segment of the public as being willing to transport for hire, indiscriminately. Las Vegas Hacienda, Inc. v. Civil Aeronautics Bd., 298 F.2d 430 (9th Cir.), cert. denied, 369 U.S. 885, 82 S.Ct. 1158, 8 L.Ed.2d 286 (1962); East Coast Flying Serv. Enforcement Proceeding, 46 C.A.B. 640 (1967); M R Inv. Co., Inc. v. Civil Aeronautics Bd., 308 F.2d 49 (9th Cir. 1962); Arrow Aviation, Inc. v. Moore, 266 F.2d 488 (8th Cir. 1959); Southeastern Aviation, Inc. Enforcement Proceeding, 32 C.A.B. 1281 (1961); Consolidated Flower Shipments, Inc., 16 C.A.B. 804 (1953), aff'd, Consolidated Flower Shipments v. Civil Aeronautics Bd., 213 F.2d 814 (9th Cir. 1954); Intercontinental Enforcement Proceeding, 41 C.A.B. 583 (1965). The test "is an objective one, relying upon what the carrier actually does rather than upon the label which the carrier attaches to its activity or the purpose which motivates it." Las Vegas Hacienda, 298 F.2d at 434.

The cases which Woolsey cites in support of his definition of "common carriage" are distinguishable. Most of these cases involve definitions of common carriage developed outside the context of aviation law. See, e.g., Terminal Taxicab v. Dist. of Columbia, 241 U.S. 252, 36 S.Ct. 583, 60 L.Ed. 984 (1916) (taxicabs); Semon, 279 F.2d 737 (fishing boat); Home Ins. Co. v. Riddell, 252 F.2d 1 (5th Cir. 1958) (trucks). We agree with the Ninth Circuit that these cases are inapposite:

It would be wholly unjustified simply to assume that the [disputed] terms are to have the precise meaning attached to them in the definitions of the Motor Carrier Act and in the case law under that statute. . . . We have been warned of the impropriety of assuming that Congress intended that judicial precedents and rules of interpretation applicable to the regulation of other forms of transportation were to be applied to the regulation of transportation by air: "However useful parallels with older forms of transit may be in adjudicating private rights, we see no reason why the efforts of the Congress to foster and regulate development of a revolutionary commerce that operates in three dimensions should be judicially circumscribed with analogies taken over from two-dimensional transit."

Las Vegas Hacienda, 298 F.2d at 437, 439 n. 31 ( quoting Chicago Southern Air Lines, Inc. v. Waterman S.S. Corp., 333 U.S. 103, 108, 68 S.Ct. 431, 434-35, 92 L.Ed. 568 (1948)).

The few cases cited by Woolsey which do concern aviation law are either distinguishable or only weakly support his argument in dicta. See, e.g., Jackson v. Stancil, 253 N.C. 291, 116 S.E.2d 817 (1960) (where appellant did not list his business in the telephone book or advertise in any other fashion, and was affirmatively sought out by a former flying student for a single incident of transportation, appellant engaged in private or contract carriage; quoting with approval two early commentators who advanced test for common carriage involving holding out, uniform tariffs, and willingness to serve all persons aircraft can accommodate, but applying more multifaceted test for common carriage in which holding out was dispositive factor); Seven Seas Airlines, Inc., Enforcement Proceeding, 34 C.A.B. 45 (June 26, 1961) (noting in dicta that "if a carrier is not required to dedicate or assign to the exclusive use of certain patrons any particular equipment or if there is nothing to prevent a carrier from hauling with any such equipment, it has been held that the carriage is common"; but not stating that dedication of an airplane to the exclusive use of a single party necessarily would constitute private or contract carriage); Scarborough v. Aeroservice, Inc., 155 Neb. 749, 53 N.W.2d 902 (1952) (owner of a school for airplane mechanics, who agreed to transport one of his students on a single 45-minute flight, was private carrier).

There was substantial evidence, even excluding Exhibits A-11 through A-15, on which the administrative law judge and the NTSB could conclude that PTI had held itself out as being willing to serve all members of the music industry who were able to pay for its services. Although Woolsey claims that PTI was "discriminating" about whom it would serve, there is no evidence that PTI ever turned away any member of the music industry who was able to pay PTI's fees. On these facts alone, the NTSB was justified in concluding that PTI acted as a common carrier.

Woolsey claims that because PTI does not utilize uniform tariffs, it is not a common carrier. While most common carriers do utilize uniform tariffs applicable to all who apply for service, we agree with the FAA that the "absence of tariffs or rate schedules, transportation only pursuant to separately negotiated contracts, or occasional refusals to transport, are not conclusive proof that the carrier is not a common carrier." Advisory Circular at 1. See East Coast Flying Serv., 46 C.A.B. at 644; Southeastern Aviation, 32 C.A.B. at 1284-85. The existence of a contract negotiated for a special price does not alone suffice to make the carrier a private carrier. See, e.g., Las Vegas Hacienda, 298 F.2d at 434; Intercontinental, 41 C.A.B. at 601-02; Southeastern Aviation, 32 C.A.B. at 1285.

What is crucial is that the common carrier defines itself through its own marketing efforts as being willing to carry any member of that segment of the public which it serves. In this case there was sufficient evidence on which the NTSB could conclude that Prestige Touring had marketed itself to numerous rock stars, and sought to enter and capture the country music industry by directly soliciting the business of country music luminaries like McEntire.

Woolsey claims he structured the contract between PTI and Reba's Business, Inc., in order to make it comport with the requirements of FAR Part 91.501 (subpart F), 14 C.F.R. § 91.501, which does not apply in conjunction with Part 135. The exception to Part 135 on which Woolsey relies is found at FAR Part 91.501(b)(6), which states that "Operations that may be conducted under the rules in this subpart instead of those in parts 121, 129, 135, and 137 of this chapter when common carriage is not involved, include — . . . The carriage of company officials, employees, and guests of the company on an airplane operated under a time sharing . . . agreement . . ." (emphasis added). The term "time sharing agreement" is defined in FAR Part 91.501(c)(1) as "an arrangement whereby a person leases his airplane with flight crew to another person, and no charge is made for the flights conducted under that arrangement other than those specified in paragraph (d) of this section." Woolsey claims that PTI charged no more than permitted by the regulation. The FAA appears to concede in its brief that "[Subpart F] provides for certain limited exceptions to the requirement that passenger-carrying operations conducted in air commerce for compensation or hire (in the type aircraft Woolsey was using) be conducted under Part 135, the operating rules applicable to air taxi and commercial operators. If Woolsey's operations in fact met the requirements set forth in FAR § 91.501, it appears that he could have conducted those operations under the rules of that subpart, rather than under the more stringent requirements of FAR Part 135." Respondents' concession is more apparent than real, however, for the exceptions to application of Part 135 to operations like those which took place in the instant case would apply only with respect to private or contract carriers.

Because we have affirmed the finding of the NTSB that the aircraft used for the flights in question were operated by Woolsey in common carriage, we find that Mr. Woolsey's claim that he intended to bring these operations under Part 91 is unavailing. The objective conduct of PTI, holding out its services to the music industry and actually serving scores of different musicians, makes PTI's operations subject to FAR Part 135. The subjective intentions of Woolsey are not controlling. It is the objective conduct of himself and his corporation which bring their actions under FAR Part 135. Las Vegas Hacienda, 298 F.2d at 434. See also Consolidated Flower Shipments, 16 C.A.B. at 805 ("[A] carrier cannot divest itself of its common-carrier status by the simple expedient of entering into an agreement with its customers purporting to relieve itself of its normal liability"). The Federal Aviation Regulations are primarily designed to protect the public safety, and not the private contractual aspirations of given parties.

CONCLUSION

We have arrived at our destination: AFFIRMED.