[Federal Register Volume 62, Number 200 (Thursday, October 16, 1997)]
[Rules and Regulations]
[Pages 53733-53737]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-27504]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. 136CE, Special Condition 23-ACE-88]


Special Conditions; Ballistic Recovery Systems Cirrus SR-20 
Installation

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are being issued to become part of 
the type certification basis for the Ballistic Recovery Systems, Inc., 
(BRS) parachute recovery system installed in the Cirrus SR-20 Model 
airplane. This system is referred to as the General Aviation Recovery 
Device (GARD). Airplanes modified to use this system will incorporate 
novel or unusual design features for which the applicable airworthiness 
regulations do not contain adequate or appropriate safety standards. 
These special conditions contain the additional airworthiness standards 
that the Administrator considers necessary to establish a level of 
safety equivalent to the original certification basis for these 
airplanes.

EFFECTIVE DATE: November 17, 1997.

FOR FURTHER INFORMATION CONTACT: Lowell Foster, Aerospace Engineer, 
Standards Office (ACE-110), Small Airplane Directorate, Aircraft 
Certification Service, Federal Aviation Administration, 601 East 12th 
Street, Kansas City, Missouri 64106; telephone (816) 426-5688.

SUPPLEMENTARY INFORMATION:

Background

    On March 7, 1996, Cirrus Design, 4515 Taylor Circle, Duluth, MN 
55811, filed an application for a type certificate (TC). Included in 
this TC application was the provision to install the BRS GARD parachute 
recovery system as standard equipment on each Cirrus Model SR-20 
airplane. The parachute recovery system is intended to recover an 
airplane in emergency situations such as mid-air collision, loss of 
engine power, loss of airplane control, severe structural failure, 
pilot disorientation, or pilot incapacitation with a passenger on 
board. The GARD system, which is only used as a last resort, is 
intended to prevent serious injuries to the airplane occupants by 
parachuting the airplane to the ground.
    The parachute recovery system consists of a parachute packed in a 
canister mounted on the airframe. A solid propellant rocket motor 
deploys the canopy and is located on the side of the canister. A door 
positioned above the canister seals the canister, parachute canopy, and 
rocket motor from the elements and provides free exit when the canopy 
is deployed. The system is deployed by a mechanical pull handle mounted 
so that the pilot and passenger can reach it. At least two separate and

[[Page 53734]]

independent actions are required to deploy the system.
    A multi-cable bridle attaches the canopy bridle to the airplane 
primary structure. The cable lengths are sized to provide the best 
airplane touchdown attitude. The cables are routed from the parachute 
canister thru the fuselage and run externally to the fuselage attach 
points. The external portion of these cables are covered with small 
frangible fairings.

Type Certification Basis

    The type certification basis for the Cirrus Model SR-20 is as 
follows: 14 CFR part 23, effective February 1, 1965, including 
Amendments 23-1 through 23-47; 14 CFR part 36, effective December 1, 
1969, including Amendments 36-1 through the amendment in effect at the 
time of U.S. certification; Equivalent Level of Safety Findings; 
Exemptions approved by the FAA (14 CFR part 11, Sec. 11.27; Section 
611(b) of the FAA Action of 1958 (49 U.S.C. 44715); and the special 
conditions adopted by this rulemaking action.

Discussion

    Special conditions may be issued and amended, as necessary, as part 
of the type certification basis if the Administrator finds that the 
airworthiness standards designated in accordance with 14 CFR part 21, 
Sec. 21.16 do not contain adequate or appropriate safety standards 
because of the novel and unusual design features of the airplane 
modification. Special conditions, as appropriate, are issued after 
public notice in accordance with Sec. 11.49 (as amended September 25, 
1989), as required by Secs. 11.28 and 11.29(b). The special conditions 
become part of the type certification basis, as provided by 
Sec. 21.17(a)(2).
    The installation of parachute recovery systems in 14 CFR part 23 
airplanes was not envisioned when the certification basis for these 
airplanes was established. In addition, the Administrator has 
determined that current regulations do not contain adequate or 
appropriate safety standards for a parachute recovery system; 
therefore, this system is considered a novel and unusual design 
feature. The flight test demonstration requirements will ensure that 
the parachute recovery system will perform its intended function 
without exceeding its strength capabilities. Demonstrations will be 
required to show that the parachute will deploy in specified flight 
conditions. These conditions are a minimum of maneuvering speed, 
VO or higher, and deployment during a one-turn spin entry. 
If the airplane does not depart , the condition is the maneuver that 
results from pro-spin control inputs held for one turn, or three 
seconds, whichever comes first.
    Occupant restraint requirements will ensure that the airplane is 
equipped with a restraint system designed to protect the occupants from 
injury during parachute deployment and ground impact. Each occupant 
seat must meet the requirements of 14 CFR part 23, Sec. 23.562 as part 
of the original certification basis.
    Requirements for parachute performance will ensure all of the 
following: (a) The parachute complies with the applicable section of 
TSO-C23c (SAE AS8015A) at the maximum airplane weights. (b) The 
parachute deployment loads do not exceed the structural strength of the 
airplane. (c) The system will provide a ground impact that does not 
result in serious injury of the passengers. (d) The system will operate 
in adverse weather conditions.
    The requirements for the functions and operations of the parachute 
recovery system will ensure all of the following: (a) There is no fire 
hazard associated with the system. (b) The installation of this system 
allows relief from another part 23 requirement, spins. For this reason, 
it will need to be operational for all flights. (c) That the system 
will work in all weather conditions that the airplane is approved to 
operate in, including the IFR and icing environments. (d) The sequence 
of arming and activating the system will prevent inadvertent 
deployment. (e) The system can be activated from either the pilot's or 
the copilot's position by various sized people. (f) The system will be 
labeled to show its identification function and operating limitations. 
(g) A warning placard will be located on the fuselage near the rocket 
motor to warn rescue crews of the ballistic system. (h) The FAA-
approved flight manual will include a thorough explanation of system's 
operation and limitations as well as the safe deployment envelope. (i) 
The occupants are protected from serious injury after touchdown in 
adverse weather.
    Requirements for protection of the parachute recovery system will 
ensure the following: the system is protected from deterioration due to 
weathering, corrosion, and abrasion; provisions are made to provide 
adequate ventilation and drainage of the airplane structure that houses 
the parachute canister.
    Requirements for a system inspection provision will ensure that 
adequate means are available to permit examination of the parachute 
recovery system components and that instructions for continued 
airworthiness are provided.
    Requirements for operating limitations of the parachute recovery 
system will ensure that the system operating limitations and deployment 
envelope are prescribed, including inspection, repacking, and replacing 
the system's parachute deployment mechanism at approved intervals.

Discussion of Comments

    Notice of Proposed Special Conditions, Notice No. 23-ACE-88, Docket 
No. 136CE was published in the Federal Register on February 6, 1997, 
and the comment period closed March 10, 1997. Following is a summary of 
the comments received and a response to each comment.
    Only one commenter responded to the notice and that was Cirrus 
Design. They offered five comments, all of which are addressed below.
    1. Comment. Paragraph 1(a). Proposed Special Condition, Docket No. 
136CE, 23-ACE-88 does not contain provisions for the flight test 
demonstration to be conducted on an aircraft having similar 
characteristics as was accepted for Docket No. 118CE, 23-ACE-76, 
Special Conditions: Ballistic Recovery Systems, Modified for Small 
General Aviation Aircraft. Cirrus proposes to modify the current 
language of 1(a) to include: ``The system may be demonstrated on an 
aircraft having similar characteristics (such as configuration, weight, 
and speed) and similar installation.'' The crucial elements here are 
the mass distribution of the aircraft and center of gravity (moment of 
inertia), the location of the riser attachments relative to the c.g., 
and the riser configurations. The flight demonstration is conclusive if 
these elements are similar. An example of this situation would be that 
of demonstrating the operation of the recovery system in a development 
prototype aircraft similar to that of the type design aircraft. It is 
only a matter of necessary conformity and degree of similarity. The 
allowance for ``similar'' aircraft flight demonstration is a logical 
inclusion and will require a case by case review. This provision was 
found acceptable for 23-ACE-76 and, therefore, is acceptable for any 
STC installations. A TC application should not, by law, require more 
stringent conditions.
    FAA Response. The special conditions for BRS installations referred 
to by Cirrus; 23-ACE-76, Docket No. 118CE, were originally intended for 
airplanes similar to the Quicksilver GT-500 and they were intended for 
general applicability for certificated small

[[Page 53735]]

airplanes. The Cirrus special conditions do not include this provision 
because they are unique to the model SR-20. On a model specific special 
condition, general applicability items are not appropriate. This does 
not imply that minor design variations in the model would require 
additional testing.
    The FAA agrees that the crucial elements are mass distribution, 
moment of inertia, riser attachments and configurations. If these 
crucial elements remain essentially constant with minor design 
variation, then credit for GARD testing should apply to both airplanes. 
This issue has been adequately addressed in this preamble and no change 
in the special conditions is necessary.
    2. Comment. Paragraph 1(b)(2). It is recommended that item 1(b)(2) 
be changed to: ``maximum allowable deployment speed with 1g normal 
load.'' The use of this type of safety equipment is in its infancy and 
analytical predictions of deployment dynamics are challenging. Based on 
this, the loads used in the design phase are estimations based on the 
best information available. The actual loads are determined during 
flight testing and fix the maximum allowable deployment speed that the 
designed structure can withstand. A requirement for a system to be 
deployed at VNE not only offers extreme risk within a 
development and certification program, but also extends beyond that 
which is necessary to offer increased safety to the pilot and 
passengers for the portion of the flight envelope reflecting the 
largest numbers of accidents. This equipment is provided to give the 
pilot an additional option for recovery in a critical situation. The 
deployment envelope should be clearly placarded; beyond which point 
system operation is prohibited/not recommended. However, the mere 
presence of the equipment does offer a certain increase in safety. This 
option to the pilot should not be totally withdrawn because of the 
potential inability of the system to be deployed at VNE. In 
order to use the GARD system for the spin ELOS, the system need only be 
safely deployed in a spin situation. Deployments at any other time are 
an increase in safety above that which is required by FARs.
    This requirement also significantly affects customer value. Not all 
aircraft [especially high performance] can offer this equipment with 
V5NE envelope capability while maintaining an overall 
aircraft value/utility, due to the severe structural requirements 
(energy as the square of the velocity). Should pilots of these aircraft 
be denied the use of this equipment when in a critical low speed 
situation? As a final note, a maximum deployment speed other than 
VNE was found to be acceptable for the GARD 150 program, 
which also began with a VNE requirement, 23-ACE-33, Special 
Conditions: Ballistic Recovery System, Inc., Modified Cessna 150/A150 
Series Airplanes and 152/A152 Model Airplanes to Incorporate the GARD-
150 System.
    FAA Response. The FAA developed the original special conditions for 
the Ballistic Recovery System GARD-150 System based on what was 
believed to be appropriate at that time. Ideally, it is desirable for 
any safety device to operate over the entire flight envelope of the 
airplane it is installed in. Based on this ideal, the original special 
conditions were intended to cover operation from stall to 
VNE. Prior to the Cessna 150 STC installing the GARD-150, 
the typical airplanes that installed a ballistic parachute recovery 
system could use the system over the entire flight envelope because 
they were very light, low performance vehicles. The Cirrus SR-20 is a 
heavy, high performance airplane by comparison. There are challenging 
technical issues to address with this installation, one of them is the 
maximum demonstrated deployment speed.
    Cirrus is installing the BRS GARD system not only for general 
safety improvements but also for relief from the spin recovery 
demonstrations required by part 23. The FAA agrees with Cirrus that a 
requirement for deployment at VNE is not relative to a 
requirement for an equivalent safety finding for spin recovery. The 
FAA, however, disagrees with Cirrus's recommended change because it is 
open ended, allowing any speed above stall to meet the special 
condition.
    The introduction of innovative safety devices, such as ballistic 
parachute recovery systems, is important to the FAA's goal of reducing 
fatal accidents. For this reason, the FAA met with representatives from 
Cirrus to discuss the maximum deployment demonstration issue. Cirrus' 
concern, as expressed in their comments, focuses on the risk of 
developing the system that will safely deploy throughout most of the 
airplane's speed range, falling just short of VNE and, 
hence, not receiving approval to install the system in their airplane. 
Furthermore, Cirrus argues that the mere presence of the GARD system 
offers a certain increase in safety; therefore, specifying a maximum 
deployment speed that may not be achievable risks negating the GARD 
system installation. This action would not be in the best interest of 
safety.
    It is important to understand that this issue does not concern 
operational deployment by pilots directly. It addresses the deployment 
tests required by this special condition for certification. The test 
airplane used for the GARD system deployments must be safely used for 
multiple deployments. This means that the airplane must remain 
airworthy after GARD system deployment so that the parachute can be cut 
away and the airplane safely landed. In operational use, the airplane 
does not need to remain airworthy after parachute deployment because it 
is committed to returning to the ground. Once the parachute is deployed 
in operation, the airplane is going to the ground and probably will not 
be in an airworthy condition after the landing. Moreover, the FAA 
should be clear that our concern is that of occupant safety. If the 
initial opening shock of the GARD system fails parts of the airframe, 
that is acceptable as long as the occupants meet the safety 
requirements of these special conditions. The point of this discussion 
is that an acceptable operational deployment of the GARD system may not 
be acceptable in the flight test deployment case because the airplane 
could sustain serious damage, preventing the completion of the flight 
test program.
    After discussing all technical points and positions, the FAA agreed 
that the appropriate course was to require a maximum deployment speed 
based on the equivalent safety finding. The equivalent safety finding 
provides relief from the spin recovery demonstration requirements of 
Sec. 23.221. The entry requirement for a spin is a stall; therefore, 
the FAA determined that an acceptable maximum demonstrated deployment 
speed for the GARD system must be at least VO, the maximum 
speed at which, with a full deflection control input, the airplane will 
stall before reaching limit load on the airframe. This will provide 
adequate margin for the safe application of the equivalent safety 
finding and reduce Cirrus' concern that their GARD system installation 
would not be approved. The FAA also acknowledges that it is Cirrus' 
goal to push the GARD system deployment speed as high as possible 
within practical constraints.
    3. Comment. Paragraph 3(b). It is suggested that this paragraph 
include ``and the parachute assembly.''
    FAA Response. The FAA agrees and will incorporate the comment.
    4. Comment. Paragraph 4(b). This paragraph states that a ``system 
failure must be shown to be extremely improbable.'' Previous 
requirements for this type of system, reference 23-ACE-

[[Page 53736]]

 76, cited that the system, ``must be shown to function reliably and to 
perform its intended function.''
    The previous requirements were appropriate for equipment that 
increases the level of safety of the airplane. Reliability of 
``extremely improbable,'' as defined in AC 23-1309, cannot be 
reasonably shown quantitatively. The system, as designed, can deliver 
functional reliability. The testing required on incipient spin recovery 
will not quantify a demonstration of ``extremely improbable.''
    The critical firing system is designed with similar methodology as 
redundant load path structure. There are two firing primers, where only 
one is necessary for ignition of the rocket. The remainder of the 
system is mechanical in nature with few parts. The following is offered 
as a possible change to the wording: ``activation system must be shown 
to function reliably [such as redundant ignition sources] and to 
perform its intended function.''
    FAA Response. The FAA agrees in principle with Cirrus' comments 
concerning reliability. The following changes are included in these 
special conditions.
    ``Discussion'' section:
    The probability that the system will operate as designed is very 
high.
    ``Special Conditions'' section:
    The system must be shown to perform its intended function with a 
high probability that it will operate as designed.
    5. Comment. Paragraph 7(b). Based on the comments of Paragraph 
1(b)(2) above, it is also recommended that 7(b) be removed from this 
special condition. Again, the ELOS does not maintain applicability to 
the high speed portion of the flight envelope and, therefore, the 
equipment should not be required to operate in this speed range.
    FAA Response. Addressed in the earlier discussion concerning 
deployment demonstration at VNE.

Conclusion

    The following special conditions are issued for the Cirrus SR-20 
airplane. This action affects only novel and unusual design features on 
specified model/series airplanes. It is not a rule of general 
applicability and affects only those applicants who apply to the FAA 
for approval of these features on these airplanes.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, and Signs and Symbols.

Citation

    The authority citation for this special condition is as follows:

    Authority: 49 U.S.C. 106(g), 40113 and 44701; 14 CFR 21.16 and 
101; and 14 CFR 11.28 and 11.49.

Adoption of Special Conditions

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration issues the following 
special conditions as part of the type certification basis for the 
Cirrus Model SR-20 airplanes:

1. Flight Test Demonstration

    (a) The system must be demonstrated in flight to satisfactorily 
perform its intended function, without exceeding the system deployment 
design loads, for the critical flight conditions.
    (b) Satisfactory deployment of the parachute must be demonstrated, 
at the most critical airplane weight and balance, for the following 
flight conditions:
    (1) One of the two maneuvers, (i) or (ii), must be performed for 
the low speed end of the flight envelope;
    (i) Spin with deployment at one turn or 3 seconds, whichever is 
longer; or
    (ii) Deployment immediately following the maneuver that results 
from a pro-spin control input held for one turn or 3 seconds, whichever 
is longer.
    (2) A minimum of maneuvering speed, VO or higher;

2. Occupant Restraint.

    Each seat in the airplane must be equipped with a restraint system, 
consisting of a seat belt and shoulder harness, that will protect the 
occupants from head and upper torso injuries during parachute 
deployment and ground impact at the critical load conditions.

3. Parachute Performance

    (a) The parachute must comply with the applicable requirements of 
TSO-C23c, or an approved equivalent, for the maximum airplane weight at 
paragraph 1(b)(2).
    (b) The loads during deployment must not exceed 80 percent of the 
ultimate design load for the attaching structure, the cabin structure 
surrounding the occupants, and any interconnecting structure of the 
airplane.
    (c) It must be shown that, although the airplane structure may be 
damaged, the airplane impact during touchdown will result in an 
occupant environment in which serious injury to the occupants is 
improbable.
    (d) It must be shown that, with the parachute deployed, the 
airplane can impact the ground in various adverse weather conditions, 
including winds up to 15 knots, without endangering the airplane 
occupants.

4. System Function and Operations

    (a) It must be shown that there is no fire hazard associated with 
activation of the system.
    (b) The system must be shown to perform its intended function with 
a high probability that it will operate as designed.
    (c) It must be shown that reliable and functional deployment in the 
adverse weather conditions that the airplane is approved for have been 
considered. For example, if the aircraft is certified for flight into 
known icing, and flight test in actual icing reveals that ice may cover 
the deployment area, then the possible adverse effects of ice or an ice 
layer covering the parachute deployment area should be analyzed.
    (d) It must be shown that arming and activating the system can only 
be accomplished in a sequence that makes inadvertent deployment 
extremely improbable.
    (e) It must be demonstrated that the system can be activated 
without difficulty by various sized people, from a 10th percentile 
female to a 90th percentile male, while sitting in the pilot or copilot 
seat.
    (f) The system must be labeled to show its identification, 
function, and operating limitations.
    (g) A warning placard must be located on the fuselage near the 
rocket motor warning of the rocket.
    (h) The FAA-approved flight manual must include a thorough 
explanation of operation and limitations as well as the safe deployment 
envelope.
    (i) It must be shown that the occupants will be protected from 
serious injury after touchdown under various adverse weather 
conditions, including high winds.

5. System Protection

    (a) All components of the system must provide protection against 
deterioration due to weathering, corrosion, and abrasion.
    (b) Adequate provisions must be made for ventilation and drainage 
of the parachute canister and associated structure to ensure the sound 
condition of the system.

6. System Inspection Provisions

    (a) Instructions for continued airworthiness must be prepared for 
the system that meet the requirements of Sec. 23.1529.
    (b) Adequate means must be provided to permit the close examination 
of the parachute and other system components to ensure proper 
functioning, alignment,

[[Page 53737]]

lubrication, and adjustment during the required inspection of the 
system.

7. Operating Limitations

    (a) Operating limitations must be prescribed to ensure proper 
operation of the system within its deployment envelope. A detailed 
discussion of the system, including operation, limitations and 
deployment envelope must be included in the Airplane Flight Manual.
    (b) The deployment envelope of the GARD system must be possible at 
speeds up to VO or higher.
    (c) Operating limitations must be prescribed for inspecting, 
repacking, and replacing the parachute and deployment mechanism at 
approved intervals.

    Issued in Kansas City, Missouri on September 30, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate Aircraft Certification Service.
[FR Doc. 97-27504 Filed 10-15-97; 8:45 am]
BILLING CODE 4910-13-P