[Federal Register Volume 84, Number 225 (Thursday, November 21, 2019)]
[Rules and Regulations]
[Pages 64194-64195]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-25292]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 27

[Docket No. FAA-2019-0106; Notice No. 27-046-SC]


Special Conditions: Robinson Helicopter Company, Model Robinson 
R66, Visual Flight Rules Autopilot and Stability Augmentation System 
(AP/SAS System)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Robinson 
Helicopter Company (Robinson) Model R66 helicopter. This helicopter 
will have a novel or unusual design feature associated with 
installation of the autopilot and stability augmentation system (AP/SAS 
system). The applicable airworthiness regulations do not contain 
adequate or appropriate safety standards for this design feature. These 
special conditions contain the additional safety standards that the 
Administrator considers necessary to establish a level of safety 
equivalent to that established by the existing airworthiness standards.

DATES: These special conditions are effective December 23, 2019.

FOR FURTHER INFORMATION CONTACT: Andy Shaw, Aerospace Engineer, FAA, 
Rotorcraft Standards Branch, Policy and Innovation Division, 10101 
Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5384; email 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    On June 8, 2018, Robinson applied to amend type certificate (TC) 
Number R00015LA to install an AP/SAS system on the Robinson Model R66 
helicopter. The Robinson Model R66 helicopter is a 14 CFR part 27 
normal category, single turbine engine, conventional helicopter 
designed for civil operation. This helicopter model is capable of 
carrying up to four passengers with one pilot and has a maximum gross 
weight of up to 2,700 pounds, depending on the model configuration. The 
major design features include a 2-blade main rotor, an anti-torque tail 
rotor system, a skid landing gear, and a visual flight rule basic 
avionics configuration. Robinson proposes to modify this model 
helicopter by installing an AP/SAS system.
    The AP/SAS system provides attitude stabilization in two or three 
axes (pitch and roll with optional yaw) as well as higher-level 
autopilot functions such as altitude hold, heading command and 
navigation tracking. However, the possible failure conditions for this 
system, and their effect on the continued safe flight and landing of 
the helicopter, are more severe than those envisioned by the present 
rules.
    The effect on safety is not adequately covered under 14 CFR 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) was 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.

Type Certification Basis

    Under 14 CFR 21.101, Robinson must show that the Model R66 
helicopter, as modified by the installed AP/SAS, continues to meet the 
applicable regulations in effect on the date of application for the 
change to the type certificate. The baseline certification basis for 
the unmodified Robinson Model R66 helicopter is listed in TC Number 
R00015LA. 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 amended 
TC, do not contain adequate or appropriate safety standards for the 
Robinson Model R66 helicopter 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, Robinson must show compliance of the AP/SAS amended TC 
altered model R66 helicopter 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 Robinson Model R66 helicopter will incorporate the following 
novel or unusual design features: AP/SAS. An autopilot (AP) is a system 
used to control the trajectory of an aircraft without constant input 
from the pilot. This allows the pilot to focus on other aspects of 
operations such as weather and systems. A stability augmentation system 
(SAS) is another type of automatic flight control system; however, 
instead of maintaining the aircraft on a predetermined attitude or 
flight path, the SAS will reduce pilot workload by dampening aircraft 
buffeting regardless of the attitude or flight path.

Discussion

    To comply with the provisions of the special conditions, the FAA 
requires that Robinson provide the FAA with a systems safety assessment 
(SSA) for the final AP/SAS installation configuration that will 
adequately address the safety objectives established by a functional 
hazard assessment (FHA). This process will ensure that all failure 
conditions and their resulting effects are adequately addressed for the 
installed AP/SAS. The SSA process is part 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 AP/SAS installed on a 
Robinson Model R66 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 conditions are classified according to the severity of 
their effects on 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 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

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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. Environmental qualification provides data to show that the 
AP/SAS system can perform its intended function under the expected 
operating condition. Some of the main considerations for environmental 
concerns are installation locations and the resulting exposure to 
environmental conditions for the AP/SAS system equipment, including 
considerations for other equipment that may also be affected 
environmentally by the 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.

Discussion of Comments

    Notice of proposed special conditions No. 27-046-SC for the 
Robinson Model R66 helicopter was published in the Federal Register on 
June 26, 2019 (84 FR 30050). Comments were received from two 
commenters. The commenters stated that special conditions previously 
issued for an AP/SAS system on a different model helicopter were more 
aligned with rulemaking whereas this special condition text seemed more 
appropriate for guidance material. The commenters requested the FAA 
change the proposed special conditions to be consistent with those 
previously issued for the same type of equipment. The FAA agrees that 
an effort should be made to maintain consistency and has revised the 
proposed special conditions to align with previously issued special 
conditions.
    The commenters also noted the Discussion section of the proposed 
special conditions contains references to specific revisions of RTCA 
Document DO-178 and RTCA Document DO-160G and requested these 
references to specific revisions be removed. The FAA disagrees, however 
an applicant may request to use a later approved revision to these 
documents if the applicant shows the later revision meets the safety 
level intended by the special condition.
    Except for the changes previously discussed, these special 
conditions are adopted as proposed.

Applicability

    These special conditions are applicable to the AP/SAS installed as 
an amended TC approval in Robinson Model R66 helicopter, TC Number 
R00015LA.

Conclusion

    This action affects only certain novel or unusual design features 
for an AP/SAS amended TC installed on one model helicopter. 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, Reporting and recordkeeping 
requirements.

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

The Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) issues the 
following special conditions as part of the amended type certification 
basis for installation of the autopilot and stability augmentation 
system (AP/SAS) on Robinson Model R66 helicopters.
    Instead of the requirements of 14 CFR 27.1309(b) and (c), the 
following must be met for certification of the AP/SAS system installed 
on Robinson Model R66 helicopters:
    a. The equipment and systems must be designed and installed so that 
any equipment and systems do not adversely affect the safety of the 
rotorcraft or its occupants.
    b. The rotorcraft systems and associated components considered 
separately and in relation to others systems, must be designed and 
installed so that:
    (1) The occurrence of any catastrophic failure condition is 
extremely improbable;
    (2) The occurrence of any hazardous failure condition is extremely 
remote; and
    (3) The occurrence of any major failure condition is remote.
    c. Information concerning an unsafe system operating condition must 
be provided in a timely manner to the crew to enable them to take 
appropriate corrective action. An appropriate alert must be provided if 
immediate pilot awareness and immediate or subsequent corrective action 
is required. Systems and controls, including indications and 
annunciations, must be designed to minimize crew errors which could 
create additional hazards.

    Issued in Fort Worth, Texas, on November 13, 2019.
Jorge Castillo,
Manager, Rotorcraft Standards Branch, Policy and Innovation Division, 
Aircraft Certification Service.
[FR Doc. 2019-25292 Filed 11-20-19; 8:45 am]
 BILLING CODE 4910-13-P