Exemption No. 10424 

UNITED STATES OF AMERICA 

DEPARTMENT OF TRANSPORTATION 

FEDERAL AVIATION ADMINISTRATION 

WASHINGTON, DC 20591 

 

In the matter of the petition of 

 

MARYLAND STATE POLICE Regulatory Docket No. FAA-2011-1029 

AVIATION COMMAND 

 

for an exemption from § 47.15(b) 

of Title 14, Code of 

Federal Aviation Regulations 

 

DENIAL OF EXEMPTION 

 By letter dated September 12, 2011, Mr. Williams S. Bernard, Director-Flight Operations, 

Maryland State Police Aviation Command (MSPAC), 3023 Strawberry Point Rd., Baltimore, 

Maryland 21220, petitioned the Federal Aviation Administration (FAA) on behalf of the 

MSPAC for an exemption from § 47.15(b) of Title 14, Code of Federal Regulations 

(14 CFR). The proposed exemption, if granted, would allow it to obtain special registration 

numbers for their new fleet of AW139 aircraft. 

The petitioner requests relief from the following regulation:

Section 47.15(b) prescribes that “A U.S. registration number may not exceed five 

symbols in addition to the prefix letter “N.” These symbols may be all numbers 

(N10000), one to four numbers and one suffix letter (N1000A), or one to three numbers 

and two suffix letters (N100AB). The letters “I” and “O” may not be used. The first 

zero in a number must always be preceded by at least one of the numbers 1 through 9.” 

The petitioner supports its request with the following information:

The petitioner states it would like to use the registration numbers “N1MSP” through 

“N11MSP” for its new AW139 fleet. The petitioner notes that MSPAC has gone to 

great lengths in the design and appearance of the new aircraft, which will visibly be 

marked with “Maryland State Police.” The requested registration numbers will 

enhance the appearance and make it obvious as to the identity of the aircraft operator. 

AFS-11-463-E 
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In addition, the Maryland citizens fund the medevac program through a transportation 

surcharge added to their registration fees. If these numbers are allowed to be used, 

when the citizens see these helicopters “they will identify with their support and an 

understanding of the multi mission profile of over 140,000 medevacs in the programs 

history.” Use of these registration numbers would also make it easier to track aircraft 

and maintenance. 

The petitioner feels that since its request deals strictly with the aircraft registration and 

not how the aircraft are operated, this exemption would not adversely affect safety. 

 A summary of the petition was published in the Federal Register on October 24, 2011 

(76 FR 65772). No comments were received. 

The FAA’s analysis is as follows: 

Section 47.15(b) defines the configuration of a United States aircraft registration 

number. It provides notice worldwide to the format of a valid United States aircraft 

registration number. This information is reproduced in countless publications and the 

parameters are part of computer systems worldwide. 

The FAA, Civil Aviation Registry, Aircraft Registration Branch (Registry), has five 

components to their computer system: 1) Aircraft Registration Database, 2) Document 

Control System, 3) Registration Modernization System, 4) Electronic Data Retrieval 

System, and 5) The FAA Aircraft Registration Website. The system infrastructure is 

designed to accept the configuration of the registration number as defined in 

§ 47.15(b). 

All aircraft records on the United States Civil Aircraft Register are maintained through 

the Aircraft Registration Database, Document Control System, Registration 

Modernization System, and Electronic Data Retrieval System components of the 

Registry computer system. Records are stored as digital images. All aircraft records 

are public records and copies are available to anyone upon request. 

Controls have been programmed into the Registry’s computer system to prevent 

accepting data and the creation of an aircraft record for registration numbers that do not 

meet the criteria in § 47.15(b). MSPAC states that it has made N-number inquiries for 

both “N1MSP” and “N11MSP” in the FAA Civil Aviation Registry website. The 

responses were “Not Assigned/Reserved” and did not indicate “incorrect or impossible 

elements.” An N-Number inquiry is a query for a registration number. If the system 

finds the registration number is reserved, assigned, or a cancelled record, it will display 

pertinent information, e.g., last registered owner’s name and address, etc. This is not to 

be confused with the acceptance of data which includes document images, actions 

taken with these documents, and a multitude of other components. The correct 

response to the queries in the website should have been “N-number Not Valid.” The 
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Registry was not aware of this and has forwarded this information to the office 

responsible for the website. 

To allow assignment of these numbers would first require reprogramming of all 

components of the computer system to accept registration numbers with three suffix 

letters. It would also configure the computer system to accept registration numbers that 

do not comply with § 47.15(b). It would be a far-reaching, labor-intensive, monetarily 

costly, time-consuming modification. The Registry’s computer system is also 

interconnected to many other FAA systems, including Air Traffic Control, and other 

law enforcement and international programs, all of which would require program 

modifications and funding for the accommodation. If this exemption is granted, these 

registration numbers could not be used until all modifications to all FAA computer 

systems are accomplished and all FAA personnel are notified of this exemption. A 

definite date would be difficult to determine. 

The International Civil Aviation Organization (ICAO) sets the standards and 

regulations necessary for international aviation safety, security, and environmental 

protection on a global basis. It serves as the primary forum for cooperation in all fields 

of civil aviation among its Member States. The United States of America is a Member 

State. The primary obstacle to the grant of this exemption involves the ICAO aircraft 

addresses. It is not a coincidence that the total number of N-Numbers available for 

assignment to U.S. aircraft is exactly the same as the total number of ICAO addresses 

allocated to the Registry. ICAO provides an allocation of 24-bit aircraft addresses to 

the Member States. These 24-bit address patterns represent the most significant bit 

(MSB) of the address. There is a complex algorithm that defines the correspondence 

between the ICAO address, the Mode ‘S’ address, and the N-number. Each N-number 

has a specific ICAO address associated with it. Modifying the length and composition 

of the current N-number structure would obstruct compliance with the world-wide 

scheme for allocation, assignment, and application of aircraft addresses. 

MSPAC has not demonstrated how the use of 11 “special” registration numbers would 

make the aircraft operator more obvious to Maryland citizens, has not shown how it 

would benefit the public in general, and did not explain how it would make it easier to 

track the aircraft and maintenance. If the exemption was granted, the cost in time, 

money, and personnel, to the FAA and all the other government agencies affected, 

would be a burden to the taxpaying public. The allowance to use these numbers would 

also cause confusion to many of the aviation community who see these aircraft, which 

would lead to multiple inquiries to FAA offices, airports, and law enforcement 

agencies, regarding the validity of the registration numbers and aircraft ownership. 
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The FAA’s Decision: 

 In consideration of the foregoing, I find that a grant of exemption would not be in the 

public interest. Therefore, pursuant to the authority contained in 49 U.S.C. §§ 40113 

and 44701, delegated to me by the Administrator, the petition of Maryland State Police 

Aviation Command for an exemption from 14 CFR § 47.15(b) is hereby denied. 

Issued in Washington, D.C., on January 6, 2012. 

/s/ 

John W. McGraw 

Acting Director, Flight Standards 

 Service