RVSM Maintenance

March 1, 2005
RVSM installation requirements.

March 2005

The requirements for maintaining the special equipment (and standard equipment) associated with an RVSM installation are really much more straight-forward than you may think. In this issue we will outline and walk through how the requirements are established and the rules that govern RVSM equipment inspection and maintenance requirements.

Let's begin by taking a look at the regulation written to facilitate operations under RVSM.

We begin with 14 CFR Part 91.706 -- "Operations within airspace designated as Reduced Vertical Separation Minimum Airspace". The rule states:

(a) Except as provided in paragraph (b) of this section, no person may operate a civil aircraft of U.S. registry in airspace designated as Reduced Vertical Separation Minimum (RVSM) airspace unless:(1) The operator and the operator's aircraft comply with the requirements of Appendix G of this part; and(2) The operator is authorized by the Administrator to conduct such operations.(b) The Administrator may authorize a deviation from the requirements of this section in accordance with Section 5 of Appendix G to this part.

Simply put. In order to operate your aircraft in RVSM airspace, both the operator and the aircraft itself must conform to the requirements contained in 14 CFR Part 91 Appendix G. Following the trail, we find ourselves at 14 CFR Part 91 Appendix G looking for something a little more concise.

14 CFR Part 91 Appendix G is titled "Operations in Reduced Vertical Separation Minimum (RVSM) Airspace". There are eight sections to Appendix G.

Section 1. Definitions
Section 2. Aircraft Approval
Section 3. Operator Authorization
Section 4. RVSM Operations
Section 5. Deviation Authority Approval
Section 6. Reporting Altitude-Keeping Errors
Section 7. Removal or Amendment of Authority
Section 8. Airspace Designation

Obviously, each section has its own purpose. Let's dig in to and focus on the two sections that will answer the question "What does it take to get certified and stay certified to fly under RVSM?"

"Section 2. Aircraft Approval" basically tells us that the aircraft can be approved for RVSM operations if the "Administrator" (your local FAA inspector) is provided and finds acceptable an RVSM package prepared by the operator and the aircraft has installed all of the RVSM required equipment (also listed in Section 2). I don't want to list all of the required equipment here as you can peruse that at your leisure -- See 14 CFR Part 91 Appendix G.

The pertinent part of the requirements contained in Section 2 that often is slipped right past during this research is the requirement for the data package to be prepared by the operator and provided to the FAA. The package must include "(3) Documentation that establishes compliance with the applicable RVSM aircraft requirements of this section." What this means is documentation of the RVSM installation and the applicable maintenance requirements for that installation.

Documentation of the installation is the certification from the manufacturer that the aircraft meets the RVSM requirements (if delivered RVSM ready) or an FAA Form 337 that explains the installation of the RVSM equipment.

Maintenance requirements

As for the inspection and maintenance requirements, if the aircraft was certified from the factory as an RVSM aircraft, all of the required equipment contained in this section will be installed and will have been tested. In most cases however, the aircraft was not certified as RVSM prior to leaving the factory. If not, the aircraft will need to have been modified to include the equipment required by Appendix G. This is an important distinction. The means of installation of the RVSM equipment determines the inspection and maintenance requirements for the aircraft. Let me say that one more time: The means of installation of the RSVM equipment determines the inspection and maintenance requirements for the aircraft.

We have seen several people stand convinced that the regulations state that an RVSM aircraft must be inspected each 12 months in order to conduct RVSM operations. This simply is not true. The inspection requirements may be 12 months for one aircraft, 24 for another, and 18 or something else for another. Here is how you can determine what your requirements really are.

First you need to know if the aircraft was certified for RVSM operations by the factory (as part of the production process) or if the aircraft was certified for RVSM operations after receiving initial airworthiness certification. If the aircraft was certified during production, the inspection and maintenance requirements for the equipment will be in the inspection and maintenance manual for the aircraft.

Supplemental type certificate

More often the RVSM required equipment is installed after the aircraft has received its basic certification. This will come in the form of a supplemental type certificate (STC). The inspection and maintenance requirements for an after-market RVSM installation are included in the STC itself and are identified as Instruction for Continued Airworthiness (ICA). The maintenance requirements that are called out in an STC ICA can be as unique as the STC number since each STC is approved individually.

There are two different types of STCs to be aware of. The first is a one-time STC which is an STC that is created and approved only for one aircraft. This is common for single installations that are unique to the subject aircraft and could not be duplicated on another aircraft without significant modifications.

The second type of STC is more common and is usually just referred to as an STC. This second type is the type that provides for installation in multiple serial numbers of aircraft. When an STC is approved and used for installation in multiple aircraft the package that is created for the STC is usually more structured and organized. I mention this because it is important that you know where to find the Instructions for Continued Airworthiness (ICA) that go along with your particular installation. With a one-time STC the ICA can be a single sheet of paper that is provided when the aircraft is picked up. With STCs used for multiple aircraft there will usually be a maintenance document that includes an inspection and maintenance section. In either case it is important to get those instructions incorporated into the maintenance program for your aircraft and keep the instructions handy for reference by maintenance personnel.

Operator authorization

"Section 3. Operator Authorization" -- the second topic of concern from Appendix G is the issuance of operator authorization. The requirements of Section 2 and Section 3 of Part 91 Appendix G dovetail together here. The operator authorization must come after the aircraft has been properly modified and has received its certification. The inspection and maintenance requirements that come from the installation are required to make application as an operator.

There are three key issues to be addressed for operator certification.

  1. Maintenance and inspection procedure details.
  2. Validation and demonstration that the operator can maintain and operate the aircraft in RVSM airspace including demonstration of pilot knowledge.
  3. And for air carriers, revision to operations manual to incorporate proper policies and procedures as well as initial and recurrent pilot training.

Because the maintenance and inspection requirements are first derived by the installation for the RVSM equipment, in order to document the detailed requirements as well as create procedures for returning a noncompliant aircraft to service, the aircraft must already be RVSM ready and certified. The ICA is a good place to start and will give you specifics about what to inspect, how often, and how to make corrections to discrepancies found. In addition, the equipment to be used for testing the aircraft to determine compliance with the RVSM requirements must be under a quality control system that ensures its continued accuracy.


Some method, usually documented procedures, must be used to demonstrate to the FAA that the operator can properly maintain and operate the aircraft. The pilots will need to have been trained on RVSM operations and the operator must provide a description of how the new maintenance requirements will be tracked and monitored to ensure timely compliance with recurring inspections and maintenance.

If the operator is an air carrier operating under the requirements of Part 135 or Part 121 then as an air carrier they will have an operations manual and in some cases will also have a maintenance manual. Both of these documents are specific to the air carrier's operations and will need to be revised to incorporate the new requirements associated with the RVSM installation. The revised procedures also need to include initial and subsequent training for pilots assigned to operate an RVSM aircraft in RVSM airspace.

RVSM authorization comes in three different forms dependent upon the type of operation that operator is subject to. For air carriers, RVSM authorization is issued in the "Operation Specification" for the Air Carrier Certificate. For a standard Part 91 operator the authorization comes in the form of a "Letter of Authorization" which is simply a letter from the FAA indicating that your operation has met the requirements for the authorization. For a Part 91 Subpart K operation (fractional ownership operations) the authorization comes in the form of a "Management Specification" -- very similar to the "Operation Specification" issued to an air carrier.

In summary the maintenance requirements for RVSM aircraft are established at the time of application. The aircraft must be certified to operate in RVSM airspace and the operators must be trained and qualified to operate the aircraft in RVSM airspace. The inspection and maintenance requirements are associated with the equipment in the aircraft and are published in either the maintenance manual provided by the manufacturer of the aircraft or in the ICA provided in support of the STC installed in your aircraft. In the application package presented to the FAA for RVSM authorization, the applicant will create the inspection and maintenance procedures using the instructions from the manufacturer of the ICA as a platform.

Hopefully, we have helped to clarify where RVSM inspection and maintenance requirements are derived and the process used to obtain RVSM authorization from the FAA. Until next time.

Joe Hertzler is the president of AVTRAK Inc., an Aurora, Colorado-based company. He is an Airframe and Powerplant mechanic with Inspection Authorization and also a private pilot.