[Federal Register Volume 79, Number 127 (Wednesday, July 2, 2014)]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-15539]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2014-0420; Notice No. 25-14-06-SC]
Special Conditions: Bombardier Aerospace, Models BD-500-1A10 and
BD-500-1A11 Series Airplanes; Automatic Speed Protection for Design
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
SUMMARY: This action proposes special conditions for the Bombardier
Aerospace Models BD-500-1A10 and BD-500-1A11 series airplanes. These
airplanes will have a novel or unusual design feature associated with a
reduced margin between design cruising speed, VC/
MC, and design diving speed, VD/MD,
based on the incorporation of a high speed protection system that
limits nose down pilot authority at speeds above VD/
MD. The applicable airworthiness regulations do not contain
adequate or appropriate safety standards for this design feature. These
proposed 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
DATES: Send your comments on or before August 18, 2014.
ADDRESSES: Send comments identified by docket number FAA-2014-0420
using any of the following methods:
Federal eRegulations Portal: Go to http://www.regulations.gov/and follow the online instructions for sending your
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 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 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://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: Mark Freisthler, FAA, Airframe and
Cabin Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft
Certification Service, 1601 Lind Avenue SW., Renton, Washington 98057-
3356; telephone 425-227-1119; facsimile 425-227-1232.
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 on or before the closing
date for comments. We may change these special conditions based on the
comments we receive.
On December 10, 2009, Bombardier Aerospace applied for a type
certificate for their new Models BD-500-1A10 and BD-500-1A11 series
airplanes (hereafter collectively referred to as ``CSeries''). The
CSeries airplanes are swept-wing monoplanes with an aluminum alloy
fuselage sized for 5-abreast seating. Passenger capacity is designated
for the Model BD-500-1A10 and 125 for the Model BD-500-1A11. Maximum
takeoff weight is 131,000 pounds for the Model BD-500-1A10 and 144,000
pounds for the Model BD-500-1A11.
Bombardier Aerospace proposes to reduce the margin between
VC/MC and VD/MD required by
Title 14, Code of Federal Regulations (14 CFR) 25.335(b) based on the
incorporation of a high speed protection system in the airplane's
flight control laws. The airplane is equipped with a high speed
protection system that limits nose down pilot authority at speeds above
VC/MC and prevents the airplane from actually
performing the maneuver required under Sec. 25.335(b)(1).
These special conditions are necessary to address the proposed high
speed protection system. These proposed special conditions identify
various symmetric and non-symmetric maneuvers that will ensure that an
appropriate design dive speed is established. Symmetric (pitching)
maneuvers are specified in Sec. 25.331, ``Symmetric maneuvering
conditions.'' Non-symmetric maneuvers are specified in Sec. 25.349,
``Rolling conditions,'' and Sec. 25.351, ``Yaw maneuver conditions.''
Type Certification Basis
Under the provisions of 14 CFR 21.17, Bombardier Aerospace must
show that the CSeries airplanes meet the applicable provisions of part
25 as amended by Amendments 25-1 through 25-129.
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 CSeries airplanes 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 that incorporates the same or similar
novel or unusual design feature, the special conditions would also
apply to the other model under Sec. 21.101.
In addition to the applicable airworthiness regulations and special
conditions, the CSeries airplanes 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 under section 611 of Public Law 92-574,
the ``Noise Control Act of 1972.''
The FAA issues special conditions, as defined in 14 CFR 11.19, in
accordance with Sec. 11.38, and they become part of the type
certification basis under Sec. 21.17(a)(2).
Novel or Unusual Design Features
The CSeries airplanes will incorporate the following novel or
unusual design features: Bombardier Aerospace proposes to reduce the
margin between VC/VC and VD/
VD required by 14 CFR 25.335(b) based on the incorporation
of a high speed protection system in the airplane's flight control
laws. The high speed protection system limits nose down pilot authority
at speeds above VC/MC and prevents the airplane
from actually performing the maneuver required under Sec.
Section 25.335(b)(1) is an analytical envelope condition that was
originally adopted in Part 4b of the Civil Air Regulations in order to
provide an acceptable speed margin between design cruise speed and
design dive speed. Flutter clearance design speeds and airframe design
loads are impacted by the design dive speed. While the initial
condition for the upset specified in the rule is 1g level flight,
protection is afforded for other inadvertent overspeed conditions as
well. Section 25.335(b)(1) is intended as a conservative enveloping
condition for potential overspeed conditions, including non-symmetric
ones. To establish that potential overspeed conditions are enveloped,
Bombardier Aerospace needs to demonstrate that any reduced speed
margin, based on the high speed protection system, will not be exceeded
in inadvertent or gust-induced upsets resulting in initiation of the
dive from non-symmetric attitudes; or that the airplane is protected by
the flight control laws from getting into non-symmetric upset
conditions. Bombardier Aerospace needs to conduct a demonstration that
includes a comprehensive set of conditions, as described below.
These proposed 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
As discussed above, these special conditions are applicable to the
Model BD-500-1A10 and BD-500-1A11 series airplanes. Should Bombardier
Aerospace apply at a later date for a change to the type certificate to
include another model incorporating the same novel or unusual design
feature, the special conditions would apply to that model as well.
This action affects only certain novel or unusual design features
on two model series of airplanes. It is not a rule of general
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
The Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Bombardier Aerospace Models BD-500-1A10 and BD-500-1A11 (CSeries)
Automatic Speed Protection for Design Dive Speed
1. In lieu of compliance with Sec. 25.335(b)(1), if the flight
control system includes functions that act automatically to initiate
recovery before the end of the 20-second period specified in Sec.
25.335(b)(1), VD/MD must be determined from the
greater of the speeds resulting from conditions (a) and (b) below. The
speed increase occurring in these maneuvers may be calculated, if
reliable or conservative aerodynamic data are used.
(a) From an initial condition of stabilized flight at
VC/MC, the airplane is upset so as to take up a
new flight path 7.5 degrees below the initial path. Control
application, up to full authority, is made to try and maintain this new
flight path. Twenty seconds after initiating the upset, manual recovery
is made at a load factor of 1.5g (0.5 acceleration increment), or such
greater load factor that is automatically applied by the system with
the pilot's pitch control neutral. Power, as specified in Sec.
25.175(b)(1)(iv), is assumed until recovery is initiated, at which time
power reduction and the use of pilot-controlled drag devices may be
(b) From a speed below VC/MC, with power to
maintain stabilized level flight at this speed, the airplane is upset
so as to accelerate through VC/MC at a flight
path 15 degrees below the initial path (or at the steepest nose down
attitude that the system will permit with full control authority if
less than 15 degrees). The pilot's controls may be in the neutral
position after reaching VC/MC and before recovery
is initiated. Recovery may be initiated three seconds
after operation of the high speed warning system by application of a
load of 1.5g (0.5 acceleration increment), or such greater load factor
that is automatically applied by the system with the pilot's pitch
control neutral. Power may be reduced simultaneously. All other means
of decelerating the airplane, the use of which is authorized up to the
highest speed reached in the maneuver, may be used. The interval
between successive pilot actions must not be less than one second.
2. The applicant must also demonstrate that the speed margin,
established as above, will not be exceeded in inadvertent or gust-
induced upsets resulting in initiation of the dive from non-symmetric
attitudes, unless the airplane is protected by the flight control laws
from getting into non-symmetric upset conditions. The upset maneuvers
described in Advisory Circular 25-7C, Flight Test Guide for
Certification of Transport Category Airplanes, section 8, paragraph 32,
sub-paragraphs c(3)(a) and (b) may be used to comply with this
3. The probability of any failure of the high speed protection
system that would result in an airspeed exceeding those determined by
paragraphs 1 and 2 must be less than 10-5 per flight hour.
4. Failures of the system must be annunciated to the pilots. Flight
manual instructions must be provided that reduce the maximum operating
speeds, VMO/MMO. With the system failed, the
operating speed must be reduced to a value that maintains a speed
margin between VMO/MMO and VD/
MD that is consistent with showing compliance with Sec.
25.335(b) without the benefit of the high speed protection system.
5. Dispatch of the airplane with the high speed protection system
inoperative could be allowed under an approved MEL that would require
flight manual instructions to indicate reduced maximum operating
speeds, as described in paragraph (4). In addition, the cockpit display
of the reduced operating speeds, as well as the overspeed warning for
exceeding those speeds, must be equivalent to that of the normal
airplane with the high speed protection system operative. Also, it must
be shown that no additional hazards are introduced with the high speed
protection system inoperative.
Issued in Renton, Washington, on June 17, 2014.
Acting Manager, Transport Airplane Directorate, Aircraft Certification
[FR Doc. 2014-15539 Filed 7-1-14; 8:45 am]
BILLING CODE 4910-13-P