Volume 4 AIRCRAFT EQUIPMENT AND OPERATIONAL AUTHORIZATIONS
chapter 14 GENERAL OPERATING AND FLIGHT RULES—MAINTENANCE ISSUES
Section 15 Part
135 Transponder Requirements
4-14-15-1 PURPOSE. This section provides guidance to Maintenance and Avionics aviation
safety inspectors (ASI) concerning the requirement for an aircraft to be equipped
with a transponder meeting the standards of Technical Standard Order (TSO) TSO-C112
(Mode S) when operated under Title 14 of the Code of Federal Regulations
(14 CFR) part
135. It includes a job aid to assist you in determining compliance with the requirements
135, § 135.143(c). The job aid incorporates rule provisions and Federal Aviation
Administration (FAA) policy stated in public notices.
4-14-15-3 BACKGROUND. Section
135.143(c) prohibits the installation of non-Mode S transponders into aircraft
operated under part
135 and contains provisions for the continued use of transponders meeting
the standards of TSO‑C74b or TSO-C74c (Mode C). This rule was issued in February 1987 with an implementation date of January 1992.
A. The 1996 Notice of Proposed Rulemaking (NPRM). When this requirement
was issued, operators contended that it was premature since infrastructure had
not yet been implemented to provide a safety benefit. In response, in May 1996,
we (the FAA), issued an NPRM to evaluate rescinding the requirement. We granted
exemptions from §
135.143(c) to operators between January 1992 and October 2005.
B. Withdrawal of the 1996 NPRM. In October 2005, we issued a
public notice that our evaluation had determined that technology and infrastructure
had advanced to the point where the provisions of §
135.143(c) resulted in a safety benefit. We withdrew our 1996 NPRM and established
an effective date of March 2007, after which exemptions would no longer be reissued.
C. Exemptions. Operators of aircraft that had been operating
under exemption expressed concerns that aircraft with functional Mode C transponders
would need to have those transponders replaced or cease operation under part
135 in March 2007. In response to this concern, in February 2006, we issued
public notice that aircraft which had operated under exemption from §
135.143(c) could continue to be operated under part
135 with their existing transponder until that unit could no longer be maintained.
A. Transponder Requirement. The provisions of §
135.143(c) apply only to aircraft equipped with a transponder. An aircraft
without a transponder may be placed on an operator’s part 135 certificate and
operated in accordance with
14 CFR part
91.215. These aircraft may not operate in certain airspace without special
authorization from air traffic control (ATC).
B. Conditional Use of ATC Radar Beacon System (ATCRBS) Transponder.
The March 2007 Federal Register (FR) notice provided a provision for aircraft
to operate under part
135 with a Mode C transponder installed after January 1, 1992. The provision
applies to an aircraft with a transponder not meeting the requirements of TSO-C112,
which was installed prior to March 1, 2007 and had been operated under an exemption
135.143(c) at some time in the past.
NOTE: The exemption was aircraft specific and could include operation
of the aircraft by another operator under part
C. Multiple Transponders. Aircraft operated under part
135 meet the requirements of §
135.143(c) when they are equipped with a single Mode S transponder or are
compliant based on the provision described above. Additional transponders are
not required to also meet the provision of §
135.143(c) (i.e., they may be Mode C rather than Mode S transponders).
D. Proving Transponder Date. It may be difficult for an operator
to prove the exact date a transponder was manufactured or installed. Reasonable
proof is adequate.
E. Job Aid. The Flight Standards Service (AFS), Aircraft Maintenance
Division (AFS-300), Avionics Branch (AFS-360) has developed a job aid (see Figure
14 CFR Part
135 Transponder Requirements) to assist an ASI in determining
compliance with §
4-14-15-7 ACTION. You should use this job aid (Figure 4-71) to perform surveillance
or determine eligibility of an aircraft for operation under part
4-14-15-9 REFERENCES, FORMS, AND JOB AIDS.
· FR Volume 52, Number 22 (February 3, 1987). Air Traffic Control
Radar Beacon System and Mode S Transponder Requirements in the National Airspace
System (FR Doc No: 1987-3380).
· FR Volume 61, Number 101 (May 23, 1996). Air Traffic Control Radar
Beacon System and Mode S Transponder Requirements in the National Airspace System
(FR Doc No: 1996-26036).
· FR Volume 70, Number 194 (October 7, 2005). Mode S Transponder
Requirements in the National Airspace System (FR Doc No: 2005-58966).
· FR Volume 71, Number 31 (February 15, 2006). Mode S Transponder
Requirements in the National Airspace System (FR Doc No: 2006-7892).
B. Forms. None.
C. Job Aids. Figure 4-71,
14 CFR Part
135 Transponder Requirements.
Figure 4-71. 14 CFR Part
135 Transponder Requirements
RESERVED. Paragraphs 4-14-15-11 through 4-14-15-25.