[Federal Register Volume 76, Number 127 (Friday, July 1, 2011)]
[Rules and Regulations]
[Pages 38550-38552]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-16507]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM455; Special Conditions No. 25-438-SC]


Special Conditions: Boeing, Model 747-8 Series Airplanes; Door 1 
Extendable Length Escape Slide

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for Boeing Model 747-8 
airplanes. These airplanes will have a novel or unusual design feature 
associated with an extendable length escape slide. 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. Additional special conditions will be 
issued for other novel or unusual design features of Boeing 747-8 
airplanes.

DATES: Effective Date: August 1, 2011.

FOR FURTHER INFORMATION CONTACT: Jayson Claar, FAA, Airframe and Cabin 
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue, SW, Renton, Washington 98057-
3356; telephone (425) 227-2194; facsimile (425) 227-1232.

SUPPLEMENTARY INFORMATION:

Background

    On November 4, 2005, The Boeing Company, PO Box 3707, Seattle, WA, 
98124, applied for an amendment to Type Certificate Number A20WE to 
include the new Model 747-8 series passenger airplane. Boeing later 
applied for, and was granted, an extension of time for the type 
certificate, which changed the effective application date to December 
31, 2006. The Model 747-8 is a derivative of the 747-400. The Model 
747-8 is a four-engine jet transport airplane that will have a maximum 
takeoff weight of 975,000 pounds, new General Electric GEnx -2B67 
engines, and the capacity to carry 605 passengers.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14 
CFR) 21.101, Boeing must show that the Model 747-8 (hereafter referred 
as 747-8) meets the applicable provisions of part 25,

[[Page 38551]]

Amendments 25-1 through 25-120, plus Amendment 25-127 for Sec.  
25.795(a), except for earlier amendments as agreed upon by the FAA. 
These regulations will be incorporated into Type Certificate No. A20WE 
after type certification approval of the 747-8.
    In addition, the certification basis includes other regulations, 
special conditions, and exemptions that are not relevant to these 
special conditions. Type Certificate No. A20WE will be updated to 
include a complete description of the certification basis for these 
airplanes.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the 747-8 because of a novel or 
unusual design feature, special conditions are prescribed under the 
provisions of Sec.  21.16.
    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 or series that incorporates the same 
or similar novel or unusual design feature, or should any other model 
or series already included on the same type certificate be modified to 
incorporate the same or similar novel or unusual design feature, the 
special conditions would also apply to the other model or series under 
Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the 747-8 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.
    Special conditions, as defined in Sec.  11.19, are issued under 
Sec.  11.38, and become part of the type certification basis under 
Sec.  21.101.

Novel or Unusual Design Features

    The Boeing Model 747-8 will incorporate the following novel or 
unusual design features: The 747-8 design offers seating capacity on 
two separate decks, the main deck with a maximum passenger capacity of 
495 and the upper deck with a maximum passenger capacity of 110. 
Section 25.810(a)(1)(iii) requires that after full deployment the 
emergency escape system assist means must be long enough so that the 
lower end is self-supporting on the ground and provides safe evacuation 
of occupants to the ground after collapse of one or more legs of the 
landing gear. Typically, airplanes have fixed-length slides that meet 
the above requirements. However, it was not possible to use fixed-
length slides for the 747-8 Door 1 because of the difference between 
normal sill height and the high-sill height associated with collapse of 
some of the landing gear in an emergency. Some combinations of landing 
gear collapse could cause the airplane to tip back on its tail. The 
747-8 Door 1 escape slide is an extendable length design to meet the 
gear collapse and tail tip conditions.

Discussion

    The regulations governing the certification of the 747-8 do not 
adequately address the certification requirements for an extendable 
length escape slide. The only reference to extendable length escape 
slides in Technical Standard Order (TSO) C69c, Emergency Evacuation 
Slides, Ramps, Ramp/Slides, and Slide/Rafts, is in the inflation time 
requirement section. The requirements of Sec.  25.801(a)(1)(iii) for 
other airplanes have been addressed by a single length escape slide. 
However, for the 747-8 Door 1, it was not possible to have a single 
length escape slide because of the extreme difference in sill heights 
between normal sill height and high-sill height associated with 
collapse of some of the landing gear, and the additional case of the 
airplane tipping back on its tail. For Door 1, the normal sill height 
is approximately 187 inches, and the high-sill height is approximately 
346 inches.
    The design of the extendable length escape system has an 
approximately 12 foot long extension packed at the toe end of the 
escape slide. During normal operation, the extension portion remains 
packed at the toe end. The airplane is equipped with an electronic 
sensor that evaluates the attitude of the airplane, and determines if 
the extendable portion is needed. When the extended length is needed, 
the system sends a signal to an electronic sign on the door to indicate 
to the flight attendant that the extendable length of the slide needs 
to be inflated. The extendable length inflation system is activated by 
pulling on a separate inflation handle located on the right side of the 
slide girt.
    The Airbus A380 airplane has an extendable length slide and the FAA 
issued Special Conditions Number 25-323-SC to address the installation 
of the extendable length escape slide in that airplane. These 
previously issued special conditions provide a starting point for 
developing special conditions for the 747-8 airplane, which consider 
and evaluate the unique aspects of this airplane's design.
    The extension is intended only for use at high-sill heights. A 
typical fixed-length slide operating at high-sill height does not 
satisfy all of the performance requirements of Sec.  25.810, but its 
variations in performance are understood and largely predictable. 
Certain performance criteria are valid regardless of sill height, while 
other aspects of performance can be expected to decline at higher sill 
heights. With an extendable slide, there is a step change in 
configuration and potentially a change in performance. Therefore, 
special conditions are needed to ensure acceptable performance in the 
extended mode.
    Section 25.810 specifies the basic performance requirements for 
escape slides, including wind testing, repeatability testing, and 
testing at adverse sill heights. Section 25.1309(a) requires systems to 
perform under foreseeable operating conditions, such as extreme 
temperatures, and demonstrate that the system design is appropriate for 
its intended function. Standards for the equipment itself are in TSO-
C69c and contribute to a satisfactory installation.
    Typically, wind tests are only conducted on fixed-length slides at 
normal sill height. Since the regulations require that the escape 
slides have the capability of being deployed in 25-knot winds directed 
from the most critical angle, escape slides usually exceed 25-knot 
performance at other than the critical angle. The same is expected to 
be true of the slide in its extended mode, but some reduction in the 
required wind velocity is appropriate since the slide will be in an 
abnormal condition. Available data indicate that the capability of 
being deployed in 22-knot winds is appropriate to cover the slide in 
its extended mode at normal sill height. This corresponds to roughly 
75% of the wind energy required for the slide in its normal attitude 
and will ensure that the slide can function in its extended mode at 
least as well as a fixed-length slide under similar abnormal 
conditions.
    These special conditions also specify a rate for passenger 
evacuation that is consistent with that of fixed-length escape slides.

Discussion of Comments

    Notice of proposed special conditions No. 25-11-12-SC for Boeing 
Model 747-8 airplanes was published in the Federal Register on May 10, 
2011 (76 FR 26957). No comments were received and the special 
conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to 
Boeing Model 747-8 airplanes. Should Boeing apply at a later date for a 
change to the

[[Page 38552]]

type certificate to include another model incorporating the same novel 
or unusual design features, these special conditions would apply to 
that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
of Boeing Model 747-8 airplanes. It is not a rule of general 
applicability.

List of Subjects in 14 CFR Part 25

    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, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for Boeing Model 747-8 airplanes.
    1. The extendable escape slide must receive Technical Standard 
Order (TSO) C69c or latest TSO authorization published at the time of 
TSO application for the Door 1 Slide.
    2. In addition to the requirements of Sec.  25.810(a)(1)(iii) for 
usability in conditions of landing gear collapse, the deployed escape 
slide in the extended mode must demonstrate an evacuation rate of 45 
persons per minute per lane at the sill height corresponding to 
activation of the extension.
    3. In lieu of the requirements of Sec.  25.810(a)(1)(iv), the 
escape slide with the extendable section activated must be capable of 
being deployed in 22-knot winds directed from the critical angle, with 
the airplane on all its landing gear, with the assistance of one person 
on the ground. Two deployment scenarios must be addressed as follows:
    (a) Extendable section is activated during the inflation time of 
the basic slide and,
    (b) Extendable section is activated after the basic slide is 
completely inflated.
    4. Pitch sensor tolerances and accuracy must be taken into account 
when demonstrating compliance with Sec.  25.1309(a) for the escape 
slide in both extended and unextended modes.
    5.(a) There must be a ``slide extension'' warning such that the 
cabin crew is immediately made aware of the need to deploy the 
extendable section of the slide. The ability to provide such a warning 
must be available for ten minutes after the airplane is immobilized on 
the ground.
    (b) There must be a positive means for the cabin crew to determine 
that the extendable portion of the slide has been fully erected.
    6. Whenever passengers are carried on the main deck of the 
airplane, there must be a cabin crewmember stationed on each side of 
the airplane located near each Door 1 Exit. This special condition must 
be included in the airplane flight manual as a limitation.

    Issued in Renton, Washington, on June 22, 2011.
KC Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-16507 Filed 6-30-11; 8:45 am]
BILLING CODE 4910-13-P