[Federal Register Volume 79, Number 160 (Tuesday, August 19, 2014)]
[Rules and Regulations]
[Pages 48949-48952]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-19540]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 27
[Docket No. FAA-2014-0595; Special Conditions No. 27-031-SC]
Special Conditions: Airbus Helicopters Deutschland GmbH Model
EC135 Series Helicopters, Installation of HeliSAS Autopilot and
Stabilization Augmentation System (AP/SAS)
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions; request for comments.
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SUMMARY: These special conditions are issued for the modification of
the Airbus Helicopters Deutschland GmbH (Airbus Helicopters) Model
EC135 series helicopters. These model helicopters will have a novel or
unusual design feature after installation of the S-TEC Corporation (S-
TEC) HeliSAS helicopter autopilot/stabilization augmentation system
(AP/SAS) that has potential failure conditions with more severe adverse
consequences than those envisioned by the existing applicable
airworthiness regulations. These special conditions contain the added
safety standards the Administrator considers necessary to ensure the
failures and their effects are sufficiently analyzed and contained.
DATES: The effective date of these special conditions is August 7,
2014. We must receive your comments on or before October 3, 2014.
ADDRESSES: Send comments identified by docket number [FAA-2014-0595]
using any of the following methods:
Federal eRegulations Portal: Go to http://www.regulations.gov and follow the online instructions for sending your
comments electronically.
Mail: Send comments to Docket Operations, M-30, U.S.
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
Hand Delivery of Courier: Deliver comments to the Docket
Operations, in Room W12-140 of the West Building Ground Floor at 1200
New Jersey Avenue SE., Washington, DC between 9 a.m., and 5 p.m.,
Monday through Friday, except federal holidays.
Fax: Fax comments to Docket Operations at 202-493-2251.
Privacy: The FAA will post all comments it receives, without
change, to http://regulations.gov, including any personal information
the commenter provides. Using the search function of the docket Web
site, anyone can find and read the electronic form of all comments
received into any FAA docket, including the name of the individual
sending the comment (or signing the comment for an association,
business, labor union, etc.). DOT's complete Privacy Act Statement can
be found in the Federal Register published on April 11, 2000 (65 FR
19477-19478), as well as at http://DocketsInfo.dot.gov.
Docket: Background documents or comments received may be read at
http://www.regulations.gov. Follow the online instructions for
accessing the docket or go to the Docket Operations in Room W12-140 of
the West Building Ground Floor at 1200 New Jersey Avenue SE.,
Washington, DC, between 9 a.m., and 5 p.m., Monday through Friday,
except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Matt Wilbanks, Aviation Safety
Engineer, FAA, Rotorcraft Directorate, Regulations and Policy Group
(ASW-111), 2601 Meacham Blvd., Fort Worth, Texas 76137; telephone (817)
222-5051; facsimile (817) 222-5961; or email to [email protected].
SUPPLEMENTARY INFORMATION:
Reason for No Prior Notice and Comment Before Adoption
The FAA has determined that notice and opportunity for public
comment are unnecessary because the substance of these special
conditions has been subjected to the notice and comment period
previously and has been derived without substantive change from those
previously issued. As it is unlikely that we will receive new comments,
the FAA finds that good cause exists for making these special
conditions effective upon issuance.
Comments Invited
While we did not precede this with a notice of proposed special
conditions, we invite interested people to take part in this action by
sending written comments, data, or views. The most helpful comments
reference a specific portion of the special conditions, explain the
reason for any recommended change, and include supporting data.
We will consider all comments we receive by the closing date for
comments. We will consider comments filed late if it is possible to do
so without incurring expense or delay. We may change these special
conditions based on the comments we receive.
If you want us to let you know we received your mailed comments on
these special conditions, send us a pre-addressed, stamped postcard on
which
[[Page 48950]]
the docket number appears. We will stamp the date on the postcard and
mail it back to you.
Background
On June 18, 2013, S-TEC submitted an application to the FAA's Los
Angeles Aircraft Certification Office for a supplemental type
certificate (STC) to install a HeliSAS AP/SAS on the Airbus Helicopters
model EC135 series (EC135P1, EC135T1, EC135P2, EC135T2, EC135P2+, and
EC135T2+) helicopters. The Airbus Helicopters model EC135 series
helicopters are 14 CFR part 27 normal category, twin turbine engine,
conventional helicopters designed for civil operation. These helicopter
models are capable of carrying up to seven passengers with one pilot,
and have a maximum gross weight of up to 6,504 pounds, depending on the
model configuration. The major design features include a 3-blade, fully
articulated main rotor, an anti-torque tail rotor system, a skid
landing gear, and a visual flight rule basic avionics configuration. S-
TEC proposes to modify these model helicopters by installing a two-axis
HeliSAS AP/SAS.
Type Certification Basis
Under 14 CFR 21.115, S-TEC must show that the Airbus Helicopters
model EC135 series helicopters, as modified by the installed HeliSAS
AP/SAS, continue to meet the requirements specified in 14 CFR 21.101.
The baseline of the certification basis for the unmodified Airbus
Helicopters model EC135 series helicopters is listed in Type
Certificate Number H88EU. Additionally, compliance must be shown to any
applicable equivalent level of safety findings, exemptions, and special
conditions prescribed by the Administrator as part of the certification
basis.
The Administrator has determined the applicable airworthiness
regulations (that is, 14 CFR part 27), as they pertain to this STC, do
not contain adequate or appropriate safety standards for the Airbus
Helicopters model EC135 series helicopters because of a novel or
unusual design feature. Therefore, special conditions are prescribed
under Sec. 21.16.
In addition to the applicable airworthiness regulations and special
conditions, S-TEC must show compliance of the HeliSAS AP/SAS STC
altered Airbus Helicopters model EC135 series helicopters with the
noise certification requirements of 14 CFR part 36.
The FAA issues special conditions, as defined in Sec. 11.19, in
accordance with Sec. 11.38 and they become part of the type
certification basis under Sec. 21.101(d).
Novel or Unusual Design Features
The HeliSAS AP/SAS incorporates novel or unusual design features
for installation in an Airbus Helicopters model EC135 series
helicopter, Type Certificate Number H88EU. This HeliSAS AP/SAS performs
non-critical control functions. However, the possible failure
conditions for this system, and their effect on the continued safe
flight and landing of the helicopters, are more severe than those
envisioned by the present rules.
Discussion
The effect on safety is not adequately covered under Sec. 27.1309
for the application of new technology and new application of standard
technology. Specifically, the present provisions of Sec. 27.1309(c) do
not adequately address the safety requirements for systems whose
failures could result in catastrophic or hazardous/severe-major failure
conditions, or for complex systems whose failures could result in major
failure conditions. The current regulations are inadequate because when
Sec. 27.1309(c) were promulgated, it was not envisioned that this type
of rotorcraft would use systems that are complex or whose failure could
result in ``catastrophic'' or ``hazardous/severe-major'' effects on the
rotorcraft. This is particularly true with the application of new
technology, new application of standard technology, or other
applications not envisioned by the rule that affect safety.
To comply with the provisions of the special conditions, we require
that S-TEC provide the FAA with a systems safety assessment (SSA) for
the final HeliSAS AP/SAS installation configuration that will
adequately address the safety objectives established by a functional
hazard assessment (FHA) and a preliminary system safety assessment
(PSSA), including the fault tree analysis (FTA). This will ensure that
all failure conditions and their resulting effects are adequately
addressed for the installed HeliSAS AP/SAS. The SSA process, FHA, PSSA,
and FTA are all parts of the overall safety assessment process
discussed in FAA Advisory Circular 27-1B (Certification of Normal
Category Rotorcraft) and Society of Automotive Engineers document
Aerospace Recommended Practice 4761 (Guidelines and Methods for
Conducting the Safety Assessment Process on Civil Airborne Systems and
Equipment).
These special conditions require that the HeliSAS AP/SAS installed
on an Airbus Helicopters model EC135 series helicopter meet the
requirements to adequately address the failure effects identified by
the FHA, and subsequently verified by the SSA, within the defined
design integrity requirements.
Failure Condition Categories. Failure conditions are classified,
according to the severity of their effects on the rotorcraft, into one
of the following categories:
1. No Effect--Failure conditions that would have no effect on
safety. For example, failure conditions that would not affect the
operational capability of the rotorcraft or increase crew workload;
however, could result in an inconvenience to the occupants, excluding
the flight crew.
2. Minor--Failure conditions which would not significantly reduce
rotorcraft safety, and which would involve crew actions that are well
within their capabilities. Minor failure conditions would include, for
example, a slight reduction in safety margins or functional
capabilities, a slight increase in crew workload such as routine flight
plan changes or result in some physical discomfort to occupants.
3. Major--Failure conditions which would reduce the capability of
the rotorcraft or the ability of the crew to cope with adverse
operating conditions to the extent that there would be, for example, a
significant reduction in safety margins or functional capabilities, a
significant increase in crew workload or result in impairing crew
efficiency, physical distress to occupants, including injuries, or
physical discomfort to the flight crew.
4. Hazardous/Severe-Major.
a. Failure conditions which would reduce the capability of the
rotorcraft or the ability of the crew to cope with adverse operating
conditions to the extent that there would be:
(1) A large reduction in safety margins or functional capabilities;
(2) physical distress or excessive workload that would impair the
flight crew's ability to the extent that they could not be relied on to
perform their tasks accurately or completely; or
(3) possible serious or fatal injury to a passenger or a cabin
crewmember, excluding the flight crew.
b. ``Hazardous/severe-major'' failure conditions can include events
that are manageable by the crew by the use of proper procedures, which,
if not implemented correctly or in a timely manner, may result in a
catastrophic event.
5. Catastrophic--Failure conditions which would result in multiple
fatalities to occupants, fatalities or incapacitation
[[Page 48951]]
to the flight crew, or result in loss of the rotorcraft.
Radio Technical Commission for Aeronautics, Inc. (RTCA) Document
DO-178C (Software Considerations in Airborne Systems And Equipment
Certification) provides software design assurance levels most commonly
used for the major, hazardous/severe-major, and catastrophic failure
condition categories. The HeliSAS AP/SAS system equipment must be
qualified for the expected installation environment. The test
procedures prescribed in RTCA Document DO-160G (Environmental
Conditions and Test Procedures for Airborne Equipment) are recognized
by the FAA as acceptable methodologies for finding compliance with the
environmental requirements. Equivalent environment test standards may
also be acceptable. This is to show that the HeliSAS AP/SAS system
performs its intended function under any foreseeable operating
condition, which includes the expected environment in which the HeliSAS
AP/SAS is intended to operate. Some of the main considerations for
environmental concerns are installation locations and the resulting
exposure to environmental conditions for the HeliSAS AP/SAS system
equipment, including considerations for other equipment that may be
affected environmentally by the HeliSAS AP/SAS equipment installation.
The level of environmental qualification must be related to the
severity of the considered failure conditions and effects on the
rotorcraft.
Applicability
These special conditions are applicable to the HeliSAS AP/SAS
installed as an STC approval in Airbus Helicopters model EC135P1,
EC135T1, EC135P2, EC135T2, EC135P2+, and EC135T2+ helicopters, Type
Certificate Number H88EU.
Conclusion
This action affects only certain novel or unusual design features
for a HeliSAS AP/SAS STC installed on the specified model series of
helicopters. It is not a rule of general applicability and affects only
the applicant who applied to the FAA for approval of these features.
List of Subjects in 14 CFR Part 27
Aircraft, Aviation safety.
The authority citation for these special conditions is as follows:
Authority: 42 U.S.C. 7572, 49 U.S.C. 106(g), 40105, 40113,
44701-44702, 44704, 44709, 44711, 44713, 44715, 45303.
The Special Conditions
0
Accordingly, pursuant to the authority delegated to me by the
Administrator, the following special conditions are issued as part of
the S-TEC Corporation (S-TEC) supplemental type certificate basis for
the installation of a HeliSAS helicopter autopilot/stabilization
augmentation system (AP/SAS) on Airbus Helicopters model EC135P1,
EC135T1, EC135P2, EC135T2, EC135P2+, and EC135T2+ helicopters, Type
Certificate Number H88EU. In addition to the requirement of Sec.
27.1309(c), HeliSAS AP/SAS installations on Airbus Helicopters model
EC135P1, EC135T1, EC135P2, EC135T2, EC135P2+, and EC135T2+ helicopters
must be designed and installed so that the failure conditions
identified in the functional hazard assessment (FHA) and verified by
the system safety assessment (SSA), after design completion, are
adequately addressed in accordance with the following requirements.
Requirements
S-TEC must comply with the existing requirements of Sec. 27.1309
for all applicable design and operational aspects of the HeliSAS AP/SAS
with the failure condition categories of ``no effect,'' and ``minor,''
and for non-complex systems whose failure condition category is
classified as ``major.'' S-TEC must comply with the requirements of
these special conditions for all applicable design and operational
aspects of the HeliSAS AP/SAS with the failure condition categories of
``catastrophic'' and ``hazardous severe/major,'' and for complex
systems whose failure condition category is classified as ``major.'' A
complex system is a system whose operations, failure conditions, or
failure effects are difficult to comprehend without the aid of
analytical methods (for example, FTA, Failure Modes and Effect
Analysis, FHA).
System Design Integrity Requirements
Each of the failure condition categories defined in these special
conditions relate to the corresponding aircraft system integrity
requirements. The system design integrity requirements, for the HeliSAS
AP/SAS, as they relate to the allowed probability of occurrence for
each failure condition category and the proposed software design
assurance level, are as follows:
1. ``Major''--For systems with ``major'' failure conditions,
failures resulting in these major effects must be shown to be remote, a
probability of occurrence on the order of between 1 x 10-\5\
to 1 x 10-\7\ failures/hour, and associated software must be
developed, at a minimum, to the Level C software design assurance
level.
2. ``Hazardous/Severe-Major''--For systems with ``hazardous/severe-
major'' failure conditions, failures resulting in these hazardous/
severe-major effects must be shown to be extremely remote, a
probability of occurrence on the order of between 1 x 10-7
to 1 x 10-9 failures/hour, and associated software must be
developed, at a minimum, to the Level B software design assurance
level.
3. ``Catastrophic''--For systems with ``catastrophic'' failure
conditions, failures resulting in these catastrophic effects must be
shown to be extremely improbable, a probability of occurrence on the
order of 1 x 10-9 failures/hour or less, and associated
software must be developed, at a minimum, to the Level A design
assurance level.
System Design Environmental Requirements
The HeliSAS AP/SAS system equipment must be qualified to the
appropriate environmental level for all relevant aspects to show that
it performs its intended function under any foreseeable operating
condition, including the expected environment in which the HeliSAS AP/
SAS is intended to operate. Some of the main considerations for
environmental concerns are installation locations and the resulting
exposure to environmental conditions for the HeliSAS AP/SAS system
equipment, including considerations for other equipment that may be
affected environmentally by the HeliSAS AP/SAS equipment installation.
The level of environmental qualification must be related to the
severity of the considered failure conditions and effects on the
rotorcraft.
Test and Analysis Requirements
Compliance with the requirements of these special conditions may be
shown by a variety of methods, which typically consist of analysis,
flight tests, ground tests, and simulation, as a minimum. Compliance
methodology is related to the associated failure condition category. If
the HeliSAS AP/SAS is a complex system, compliance with the
requirements for failure conditions classified as ``major'' may be
shown by analysis, in combination with appropriate testing to validate
the analysis. Compliance with the requirements for failure conditions
classified as ``hazardous/severe-major'' may be shown by flight-testing
in combination with analysis and simulation, and the appropriate
testing to validate the analysis. Flight tests may
[[Page 48952]]
be limited for ``hazardous/severe-major'' failure conditions and
effects due to safety considerations. Compliance with the requirements
for failure conditions classified as ``catastrophic'' may be shown by
analysis, and appropriate testing in combination with simulation to
validate the analysis. Very limited flight tests in combination with
simulation are used as a part of a showing of compliance for
``catastrophic'' failure conditions. Flight tests are performed only in
circumstances that use operational variations, or extrapolations from
other flight performance aspects to address flight safety.
These special conditions require that the HeliSAS AP/SAS system
installed on an Airbus Helicopters model EC135P1, EC135T1, EC135P2,
EC135T2, EC135P2+, or EC135T2+ helicopter, Type Certificate Number
H88EU, meet these requirements to adequately address the failure
effects identified by the FHA, and subsequently verified by the SSA,
within the defined design system integrity requirements.
Issued in Fort Worth, Texas, on August 7, 2014.
Lance T. Gant,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2014-19540 Filed 8-18-14; 8:45 am]
BILLING CODE 4910-13-P