This section of the FEDERAL REGISTER

contains regulatory documents having general

applicability and legal effect, most of which

are keyed to and codified in the Code of

Federal Regulations, which is published under

50 titles pursuant to 44 U.S.C. 1510.

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REGISTER issue of each week.

Rules and Regulations Federal Register

17323 

Vol. 77, No. 58 

Monday, March 26, 2012 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 23 

[Docket No. FAA–2011–1387; Special 

Conditions No. 23–256–SC] 

Special Conditions: XtremeAir GmbH, 

XA42; Acrobatic Category 

Aerodynamic Stability 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions. 

SUMMARY: These special conditions are 

issued for the XtremeAir GmbH XA42 

airplane. The XA42 airplane has a novel 

or unusual design feature associated 

with its static stability. This airplane 

can perform at the highest level of 

aerobatic competition. To be 

competitive, the aircraft was designed 

with positive and, at some points, 

neutral stability within its flight 

envelope. Its lateral and directional axes 

are also decoupled from each other 

providing more precise maneuvering. 

The applicable airworthiness 

regulations do not contain adequate or 

appropriate safety standards for these 

design features. 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. 

These special conditions are only 

applicable to aircraft certified solely in 

the acrobatic category. 

DATES: Effective Date: April 25, 2012. 

FOR FURTHER INFORMATION CONTACT: Mr. 

Ross Schaller, Federal Aviation 

Administration, Small Airplane 

Directorate, Aircraft Certification 

Service, 901 Locust, Room 301, Kansas 

City, Missouri 64106; telephone (816) 

329–4162; facsimile (816) 329–4090. 

SUPPLEMENTARY INFORMATION: 

Background 

On May 3, 2011, XtremeAir GmbH 

applied for a type certificate for their 

new model XA42. The XA42 is certified 

under EASA authority as a dual 

category (acrobatic/utility) airplane. It 

has a two-place tandem canopy cockpit 

and a single-engine. It also features a 

conventional landing gear, conventional 

low-wing planform and is of composite 

construction. The engine is a Lycoming 

AEIO–580–B1A with a rated power of 

315 Hp at 2,700 rpm. The airplane is 

proposed to be approved for Day-VFR 

operations with no icing approval. 

The maximum takeoff weight is 2,200 

pounds in utility category, 1,874 pounds 

in acrobatic category. VNE is 225 knots, 

VNO is 185 knots and VA is 174 knots, 

indicated airspeed. Maximum altitude is 

15,000 feet. 

Acrobatic airplanes previously type 

certificated by the FAA did comply with 

the stability provisions of Subpart B of 

14 CFR part 23. However, airplanes like 

the XA42 are considered as ‘‘unlimited’’ 

acrobatic aircraft because they can 

perform at the highest level of aerobatic 

competition and can perform any of the 

maneuvers listed in the Aresti Catalog. 

Generally, the evolution of the 

‘‘unlimited’’ types of acrobatic 

airplanes, with very low mass, 

exceptional roll rates and very high G 

capabilities, in addition to power to 

mass ratios that are unique to this type 

of airplane, have led to airplanes that 

cannot comply with the stability 

provisions of the regulations. These 

airplanes can still be type-certificated, 

but in the acrobatic category only and 

with an appropriate set of special 

conditions and associated limitations. 

The FAA will only consider certifying 

the XA42 in the acrobatic category. 

XtremeAir GmbH will not be able to 

offer a utility category operating 

envelope to accommodate the increased 

fuel load designed for cross-country 

operations. The FAA does recognize 

that fuel exhaustion is one of the top 

accident causes associated with this 

class of aircraft. For this reason, the 

FAA allows XtremeAir to seek 

certification of a limited acrobatic 

envelope at a higher weight that will 

still meet the minimum load 

requirements of +6/-3 g associated with 

14 CFR, part 23, § 23.337. The XA42 

airplane would be approved for 

unlimited maneuvers at or below its 

designed unlimited acrobatic weight. 

The airplane would also be approved at 

some higher weight (for fuel) that would 

still meet the requirements of § 23.337 

for acrobatic category and may have 

restrictions on the maneuvers allowed. 

Type Certification Basis 

Under the provisions of 14 CFR, part 

21, § 21.17, XtremeAir GmbH must 

show that the XA42 meets the 

applicable provisions of part 23, as 

amended by Amendments 23–1 through 

23–59 thereto. 

Part 36 of Title 14 of the Code of 

Federal Regulations, effective December 

1, 1969, as amended by Amendments 

36–1 through 36–28. 

Not approved for ditching; 

compliance with provisions for ditching 

equipment in accordance with 14 CFR 

23.1415(a)(b) has not been 

demonstrated. 

Approved for VFR-day only. Flight in 

known icing prohibited. 

If the Administrator finds that the 

applicable airworthiness regulations 

(i.e., 14 CFR part 23) do not contain 

adequate or appropriate safety standards 

for the XA42 because of a novel or 

unusual design feature, special 

conditions are prescribed under the 

provisions of § 21.16. 

In addition to the applicable 

airworthiness regulations and special 

conditions, the XA42 must comply with 

the fuel vent and exhaust emission 

requirements of 14 CFR part 34 and the 

noise certification requirements of 14 

CFR part 36 and the FAA must issue a 

finding of regulatory adequacy pursuant 

to section 611 of Public Law 92–574, the 

‘‘Noise Control Act of 1972.’’ 

Special conditions, as defined in 

§ 11.19, are issued in accordance with 

§ 11.38 and become part of the type 

certification basis in accordance with 

§ 21.17(a)(2). 

Special conditions are initially 

applicable to the model for which they 

are issued. Should the type certificate 

for that model be amended later to 

include any other model that 

incorporates the same novel or unusual 

design feature, the special conditions 

would also apply to the other model 

under the provisions of § 21.101. 

Novel or Unusual Design Features 

The XtremeAir GmbH XA42 will 

incorporate the following novel or 

unusual design features: 

For acrobatic category airplanes with 

unlimited acrobatic capability: 


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17324 Federal Register / Vol. 77, No. 58 / Monday, March 26, 2012 / Rules and Regulations 

Neutral longitudinal and lateral static 

stability characteristics. 

Discussion 

The Code of Federal Regulations 

states static stability criteria for 

longitudinal, lateral, and directional 

axes of an airplane. However, none of 

these criteria are adequate to address the 

specific issues raised in the flight 

characteristics of an unlimited aerobatic 

airplane. Therefore, the FAA has 

determined after a flight test evaluation 

that, in addition to the requirements of 

part 21 and part 23, special conditions 

are needed to address these static 

stability characteristics. 

Accordingly, these special conditions 

are for the XtremeAir GmbH XA42 static 

stability characteristics to be certified 

solely as an acrobatic category airplane. 

Other conditions may be developed, as 

needed, based on further FAA review 

and discussions with the manufacturer 

and civil aviation authorities. 

Discussion of Comments 

A notice of proposed special 

conditions No. 23–11–02–SC for the 

XtremeAir GmbH XA42 airplanes was 

published in the Federal Register on 

December 27, 2011 (76 FR 80829). One 

comment was received; however, it 

appeared to be made in error. It 

discussed new hire training through 

approved 142 training centers, which is 

not relevant to the acrobatic category 

aerodynamic stability special conditions 

being imposed on XtremeAir GmbH’s 

XA42 airplane. For this reason, no 

further action will be taken and the 

special conditions are adopted as 

proposed. 

Applicability 

As discussed above, these special 

conditions are applicable to the XA42. 

Should XtremeAir GmbH apply at a 

later date for a change to the type 

certificate to include another model on 

the same type certificate incorporating 

the same novel or unusual design 

feature, the special conditions would 

apply to that model as well. 

Conclusion 

This action affects only certain novel 

or unusual design features on one model 

of airplane. It is not a rule of general 

applicability and it affects only the 

applicant who applied to the FAA for 

approval of these features on the 

airplane. 

List of Subjects in 14 CFR Part 23 

Aircraft, Aviation safety, Signs and 

symbols. 

Citation 

■ The authority citation for these 

special conditions is as follows: 

Authority: 49 U.S.C. 106(g), 40113 and 

44701; 14 CFR 21.16 and 21.17; and 14 CFR 

11.38 and 11.19. 

The Special Conditions 

Accordingly, pursuant to the 

authority delegated to me by the 

Administrator, the following special 

conditions are issued as part of the type 

certification basis for XtremeAir GmbH 

XA42 airplanes. 

1. Unlimited Acrobatic-Only Category 

Static Stability Requirements 

For unlimited, acrobatic-only category 

aircraft, XtremeAir GmbH XA42 will 

comply with the following stability 

special conditions in lieu of the existing 

§§ 23.171, 23.173, 23.175, and 23.177: 

(A) In place of 14 CFR part 23, 

§ 23.171 Flight—General (stability) 

requirement, comply with the following: 

SC23.171 Flight—General: The 

airplane must be neutrally or positively 

stable in the longitudinal, directional, 

and lateral axes under sections 

SC23.173 through SC23.181. In 

addition, the airplane must show 

suitable stability and control ‘‘feel’’ 

(static stability) in any condition 

normally encountered in service, if 

flight tests show it is necessary for safe 

operation. 

(B) In place of 14 CFR part 23, 

§ 23.173, Static longitudinal stability 

requirement, comply with the following: 

SC23.173 Static longitudinal stability: 

Under the conditions specified in 

SC23.175 and with the airplane 

trimmed as indicated, the characteristics 

of the elevator control forces and the 

friction within the control system must 

be as follows: 

(a) A pull must be required to obtain 

and maintain speeds below the 

specified trim speed and a push 

required to obtain and maintain speeds 

above the specified trim speed. This 

must be shown at any speed that can be 

obtained, except that speeds requiring a 

control force in excess of 40 pounds or 

speeds above the maximum allowable 

speed or below the minimum speed for 

steady unstalled flight need not be 

considered. 

(b) The stick force or position must 

vary with speed so that any substantial 

speed change results in a stick force or 

position clearly perceptible to the pilot. 

(C) In place of 14 CFR part 23, 

§ 23.175, Demonstration of static 

longitudinal stability requirement, 

comply with the following: 

SC23.175 Demonstration of static 

longitudinal stability: 

(a) Climb. The stick force curve must 

have, at a minimum, a neutrally stable 

to stable slope at speeds between 85 and 

115 percent of the trim speed, with— 

(1) Maximum continuous power; and 

(2) The airplane trimmed at the speed 

used in determining the climb 

performance required by section 

23.69(a). 

(b) Cruise. With the airplane in trim 

with power for level flight at 

representative cruising speeds at high 

and low altitudes, including speeds up 

to VNO, except that the speed need not 

exceed VH— 

(1) The stick force curve must, at a 

minimum, have a neutrally stable to 

stable slope at all speeds within a range 

that is the greater of 15 percent of the 

trim speed plus the resulting free return 

speed range, or 40 knots plus the 

resulting free return speed range, above 

and below the trim speed, except that 

the slope need not be stable— 

(i) At speeds less than 1.3 VS1; or 

(ii) For airplanes with VNE established 

under section 23.1505(a), at speeds 

greater than VNE. 

(c) Landing. The stick force curve 

must, at a minimum, have a neutrally 

stable to stable slope at speeds between 

1.1 VS1 and 1.8 VS1 with— 

(1) Landing gear extended; and 

(2) The airplane trimmed at— 

(i) VREF, or the minimum trim speed 

if higher, with power off; and 

(ii) VREF with enough power to 

maintain a 3 degree angle of descent. 

(D) In place of 14 CFR part 23, 

§ 23.177, Static directional and lateral 

stability requirement, comply with the 

following: 

SC23.177 Static directional and 

lateral stability: 

(a) The static directional stability, as 

shown by the tendency to recover from 

a wings level sideslip with the rudder 

free, must be positive for any landing 

gear and flap position appropriate to the 

takeoff, climb, cruise, approach, and 

landing configurations. This must be 

shown with symmetrical power up to 

maximum continuous power, and at 

speeds from 1.2 VS1 up to the maximum 

allowable speed for the condition being 

investigated. The angle of sideslip for 

these tests must be appropriate to the 

type of airplane. At larger angles of 

sideslip, up to that at which full rudder 

is used or a control force limit in section 

23.143 is reached, whichever occurs 

first, and at speeds from 1.2 VS1 to VO, 

the rudder pedal force must not reverse. 

(b) In straight, steady slips at 1.2 VS1

for any landing gear and flap positions, 

and for any symmetrical power 

conditions up to 50 percent of 

maximum continuous power, the rudder 

control movements and forces must 


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Federal Register / Vol. 77, No. 58 / Monday, March 26, 2012 / Rules and Regulations 17325 

increase steadily, but not necessarily in 

constant proportion, as the angle of 

sideslip is increased up to the maximum 

appropriate to the type of airplane. The 

aileron control movements and forces 

may increase steadily, but not 

necessarily in constant proportion, as 

the angle of sideslip is increased up to 

the maximum appropriate to the type of 

airplane. At larger slip angles, up to the 

angle at which the full rudder or aileron 

control is used or a control force limit 

contained in section 23.143 is reached, 

the aileron and rudder control 

movements and forces must not reverse 

as the angle of sideslip is increased. 

Rapid entry into, and recovery from, a 

maximum sideslip considered 

appropriate for the airplane must not 

result in uncontrollable flight 

characteristics. 

Issued in Kansas City, Missouri, on March 

1, 2012. 

John R. Colomy, 

Acting Manager, Small Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2012–6837 Filed 3–23–12; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. FAA–2012–0325; Notice No. 25– 

459–SC] 

Special Conditions: Airbus, A350–900 

Series Airplane; Passenger Seats With 

Non-Traditional, Large, Non-Metallic 

Panels 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions, request 

for comments. 

SUMMARY: These special conditions are 

issued for the Airbus A350–900 series 

airplane. These airplanes will have a 

novel or unusual design feature(s) 

associated with seats that include nontraditional, large, non-metallic panels 

that would affect survivability during a 

post-crash fire event. 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: The effective date of these 

special conditions is March 14, 2012. 

We must receive your comments by May 

10, 2012. 

ADDRESSES: Send comments identified 

by docket number [FAA–2012–0325] 

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 or of Courier: Take 

comments to Docket Operations in 

Room W12–140 of the West Building 

Ground Floor at 1200 New Jersey 

Avenue SE., Washington, DC between 8 

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://www.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/at any time. 

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: Jeff 

Gardlin, FAA, Airframe/Cabin Safety, 

ANM–115, Transport Airplane 

Directorate, Aircraft Certification 

Service, 1601 Lind Avenue SW., 

Renton, Washington, 98057–3356; 

telephone (425) 227–2136; facsimile 

(425) 227–1320. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

We invite interested people to take 

part in this rulemaking 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. 

Background 

On August 25, 2008, Airbus applied 

for a type certificate for their new A350– 

900 series airplane. Later, Airbus 

requested and the FAA approved an 

extension to the application for FAA 

type certification to June 28, 2009. The 

A350–900 series has a conventional 

layout with twin wing-mounted Rolls 

Royce Trent engines. It features a twin 

aisle 9-abreast economy class layout, 

and accommodates side-by-side 

placement of LD–3 containers in the 

cargo compartment. The basic A350– 

900 series configuration accommodates 

315 passengers in a standard two-class 

arrangement. The design cruise speed is 

Mach 0.85 with a Maximum Take-Off 

Weight of 591,000 lbs. Airbus proposes 

the A350–900 series to be certified for 

extended operations (ETOPS) beyond 

180 minutes at entry into service for up 

to a 420-minute maximum diversion 

time. 

The applicable airplane regulations, 

Title 14, Code of Federal Regulations 

(14 CFR) part 25, do not require seats to 

meet the more-stringent flammability 

standards required of large, non-metallic 

panels in the cabin interior. At the time 

the applicable rules were written, seats 

were designed with a metal frame 

covered by fabric, not with large, nonmetallic panels. Seats also met the thenrecently adopted standards for 

flammability of seat cushions. With the 

seat design being mostly fabric and 

metal, the contribution to a fire in the 

cabin had been minimized and was not 

considered a threat. For these reasons, 

seats did not need to be tested to heatrelease and smoke-emission 

requirements. 

Seat designs have now evolved to 

occasionally include non-traditional, 

large, non-metallic panels. Taken in 

total, the surface area of these panels is 

on the same order as the sidewall and 

overhead stowage bin interior panels. 

To provide the level of passenger 

protection intended by the 

airworthiness standards, these nontraditional, large, non-metallic panels in 

the cabin must meet the standards of 

part 25, Appendix F, parts IV and V, 

heat-release and smoke-emission 

requirements. 

Type Certification Basis 

Under Title 14, Code of Federal 

Regulations (14 CFR) 21.17, Airbus must 


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