[Federal Register Volume 60, Number 111 (Friday, June 9, 1995)]
[Rules and Regulations]
[Pages 30744-30750]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-14171]
[[Page 30743]]
_______________________________________________________________________
Part VI
Department of Transportation
_______________________________________________________________________
Federal Aviation Administration
_______________________________________________________________________
14 CFR Parts 1 and 25
Airworthiness Standards: European Transport Category Airplanes; Changes
to Advisory Circular (AC) 25-7; Final Rule and Notice
Federal Register / Vol. 60, No. 111 / Friday, June 9, 1995 /
Rules and Regulations
[[Page 30744]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Parts 1 and 25
[Docket No. 27705; Amendment Nos. 1-40 and 25-84]
RIN 2120-AF25
Revision of Certain Flight Airworthiness Standards To Harmonize
With European Airworthiness Standards for Transport Category Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: The Federal Aviation Administration (FAA) is amending part 25
of the Federal Aviation Regulations (FAR) to harmonize certain flight
requirements with the European Joint Aviation Requirements 25 (JAR-25).
This action responds to a petition from the Aerospace Industries
Association of America, Inc. and the Association Europeenne des
Constructeurs de Materiel Aerospatial. These changes are intended to
benefit the public interest by standardizing certain requirements,
concepts, and procedures contained in the airworthiness standards for
transport category airplanes.
EFFECTIVE DATE: July 10, 1995.
FOR FURTHER INFORMATION CONTACT: Donald K. Stimson, Flight Test and
Systems Branch, ANM-111, Transport Airplane Directorate, Aircraft
Certification Service, FAA, 1601 Lind Avenue SW., Renton, WA 98055-
4056; telephone (206) 227-1129, facsimile (206) 227-1320.
SUPPLEMENTARY INFORMATION:
Background
These amendments are based on Notice of Proposed Rulemaking (NPRM)
94-15, which was published in the Federal Register on April 22, 1994
(59 FR 19296). In that notice, the FAA proposed amendments to 14 CFR
parts 1 and 25 to harmonize certain airworthiness standards for
transport category airplanes with the European Joint Aviation
Requirements 25 (JAR-25). Harmonizing the U.S. and European
airworthiness standards benefits the public interest by reducing the
costs associated with showing compliance to disparate standards, while
maintaining a high level of safety.
NPRM 94-15 was developed in response to a petition for rulemaking
from the Aerospace Industries Association of America, Inc. (AIA) and
the Association Europeenne des Constructeurs de Materiel Aerospatial
(AECMA). In their petition, AIA and AECMA requested changes to
Secs. 25.143(c), 25.143(f), 25.149, and 25.201 to standardize certain
requirements, concepts, and procedures for certification flight testing
and to enhance reciprocity between the FAA and JAA. In addition, AIA
and AECMA recommended changes to FAA Advisory Circular (AC) 25-7,
``Flight Test Guide for Certification of Transport Category
Airplanes,'' to ensure that the harmonized standards would be
interpreted and applied consistently. A copy of that petition is
included in the docket.
The proposals published in NPRM 94-15 would harmonize not only the
sections of part 25 and JAR-25 addressed in the petition, but also
related sections. These proposals were developed by the Aviation
Rulemaking Advisory Committee (ARAC) and forwarded to the FAA as an
ARAC recommendation. The FAA accepted the recommendation and published
NPRM 94-15 for public comment in accordance with the normal rulemaking
process.
The Aviation Rulemaking Advisory Committee
The ARAC was formally established by the FAA on January 22, 1991
(56 FR 2190), to provide advice and recommendations concerning the full
range of the FAA's safety-related rulemaking activity. This advice was
sought to develop better rules in less overall time using fewer FAA
resources than are currently needed. The committee provides the
opportunity for the FAA to obtain firsthand information and insight
from interested parties regarding proposed new rules or revisions of
existing rules.
There are over 60 member organizations on the committee,
representing a wide range of interests within the aviation community.
Meetings of the committee are open to the public, except as authorized
by section 10(d) of the Federal Advisory Committee Act.
The ARAC establishes working groups to develop proposals to
recommend to the FAA for resolving specific issues. Tasks assigned to
working groups are published in the Federal Register. Although working
group meetings are not generally open to the public, all interested
parties are invited to participate as working group members. Working
groups report directly to the ARAC, and the ARAC must concur with a
working group proposal before that proposal can be presented to the FAA
as an advisory committee recommendation.
The activities of the ARAC will not, however, circumvent the public
rulemaking procedures. After an ARAC recommendation is received and it
is found acceptable by the FAA, the agency proceeds with the normal
public rulemaking procedures. Any ARAC participation in a rulemaking
package will be fully disclosed in the public docket.
Discussion of the Proposals
In NPRM 94-15, the FAA proposed amending certain sections of the
FAR, as recommended by the ARAC, to harmonize these sections with JAR-
25. Concurrently, the JAA circulated Notice of Proposed Amendment (NPA)
25B-261, which proposed revising JAR-25, as necessary, to ensure
harmonization in those areas for which the amendments proposed in NPRM
94-15 differ from the current JAR-25.
The FAA proposed to: (1) Introduce the term ``go-around power or
thrust setting'' to clarify certain part 25 flight requirements; (2)
revise the maximum control forces permitted for demonstrating
compliance with the controllability and maneuverability requirements;
(3) provide requirements for stick force and stick force gradient in
maneuvering flight; (4) revise and clarify the requirements defining
minimum control speed during approach and landing; (5) clarify the
procedural and airplane configuration requirements for demonstrating
stalls and revise the list of acceptable flight characteristics used to
define the occurrence of stall; and (6) require that stall
characteristics be demonstrated for turning flight stalls at
deceleration rates up to 3 knots per second.
Revisions were also proposed for AC 25-7 to ensure consistent
application of these proposed revised standards. Public comments
concerning the revisions to AC 25-7 were invited by separate notice in
the same issue of the Federal Register as NPRM 94-15 (59 FR 19303).
Proposal 1. Certain part 25 flight requirements involving flight
conditions other than takeoff (i.e., Secs. 25.119, 25.121(d),
25.145(b)(3), 25.145(b)(4), 25.145(b)(5), 25.145(c)(1), 25.149(f)(6),
and 25.149(g)(7)(ii)) specify using the maximum available takeoff power
or thrust as being representative of the appropriate maximum in-flight
power or thrust. In practice, however, the power or thrust setting used
to obtain the maximum in-flight power or thrust (commonly referred to
as the go-around power or thrust setting) usually differs from the
setting used for takeoff. In the [[Page 30745]] past, the FAA
interpreted the words ``maximum available takeoff power or thrust'' to
mean the maximum in-flight power or thrust, with the takeoff power or
thrust setting not always being ``available'' in flight. In NPRM 94-15,
the FAA proposed changing the nomenclature to ``go-around power or
thrust setting'' for clarification and to reflect terminology commonly
used in the operational environment. (The term ``go-around'' refers to
a deliberate maneuver to abort a landing attempt prior to touchdown by
applying the maximum available power or thrust, retracting flaps, and
climbing to a safe level-off altitude.)
The go-around power or thrust setting may differ from the takeoff
power or thrust setting, for example, due to the airspeed difference
between the takeoff and go-around flight conditions. In addition,
complying with the powerplant limitations of Sec. 25.1521 may result in
a lower power setting at the higher airspeeds associated with a go-
around. As another example, the controllability requirements of
Secs. 25.145(b)(3), 25.145(b)(4), 25.145(b)(5), 25.149(f), and
25.149(g) may also limit the go-around power or thrust setting to less
than that used for takeoff. Another reason to separate the takeoff and
go-around power (or thrust) nomenclature is that certification practice
has not required, and applicants have not always proposed, changing the
go-around power or thrust setting when a previously approved takeoff
power or thrust is increased.
The FAA proposed to substitute the term ``go-around power or thrust
setting'' for ``maximum available takeoff power or thrust'' in
Secs. 25.119, 25.121(d), 25.145(b)(3), 25.145(b)(4), 25.145(c)(1),
25.149(f)(6), and 25.149(g)(7)(ii). (Note that the requirement of
Sec. 25.145(b)(5) also uses the power specified in Sec. 25.145(b)(4).)
In addition, the FAA proposed to define ``go-around power or thrust
setting'' in part 1 as ``the maximum allowable in-flight power or
thrust setting identified in the performance data.'' By this revision,
the FAA intended to clarify that the applicable controllability
requirements should be based on the same power or thrust setting used
to determine the approach and landing climb performance contained in
the approved Airplane Flight Manual (AFM).
The proposed terminology referred to a power or thrust ``setting''
rather than a power or thrust to make it clear that existing engine
ratings would be unaffected. The powerplant limitations of Sec. 25.1521
would continue to apply at the go-around power (or thrust) setting.
Existing certification practices would also remain the same, including
the relationship between the power or thrust values used to comply with
the landing and approach climb requirements of Secs. 25.119 and
25.121(d). For example, the thrust value used to comply with
Sec. 25.121(d) may be greater than that used for Sec. 25.119, if the
operating engine(s) do not reach the maximum allowable in-flight thrust
by the end of the eight second time period specified in Sec. 25.119.
Proposal 2. The FAA proposed to revise the table in Sec. 25.143(c)
to match the control force limits currently provided in JAR 25.143(c).
This table prescribes the maximum control forces for the
controllability and maneuverability flight testing required by
Secs. 25.143(a) and 25.143(b). For transient application of the pitch
and roll control, the revised table would contain more restrictive
maximum control force limits for those maneuvers in which the pilot
might be using one hand to operate other controls, relative to those
maneuvers in which both hands are normally available for applying pitch
and roll control. The revised table would retain the current control
force limits for transient application of the yaw control, and for
sustained application of the pitch, roll, and yaw controls.
For maneuvers in which only one hand is assumed to be available,
the FAA proposed to reduce the maximum permissible control forces from
75 pounds to 50 pounds for pitch control, and from 60 pounds to 25
pounds for roll control. These lower control forces would be more
consistent with Sec. 25.145(b), which states that a force of 50 pounds
for longitudinal (pitch) control is ``representative of the maximum
temporary force that readily can be applied by one hand.'' In addition
to adding more restrictive control force limits for maneuvers in which
only one hand may be available to apply pitch and roll control, the FAA
proposed to reduce the maximum permissible force for roll control from
60 pounds to 50 pounds for maneuvers in which the pilot normally has
both hands available to operate the control.
The FAA proposed to further revise Sec. 25.143(c) by specifying
that the table of maximum permissible control forces applies only to
conventional wheel type controls. This restriction, also specified in
the current JAR 25.143(c), recognizes that different control force
limits may be necessary when considering sidestick controllers or other
types of control systems.
For clarification, the FAA proposed to replace the terms
``temporary'' and ``prolonged,'' used in Secs. 25.143(c), 25.143 (d),
25.143(e), and 25.145(b), with ``transient'' and ``sustained,''
respectively. ``Transient'' forces are those control forces resulting
from maintaining the intended flight path during changes to the
airplane configuration, normal transitions from one flight condition to
another, or regaining control after a failure. The pilot is assumed to
take immediate action to reduce or eliminate these forces by retrimming
or by changing the airplane configuration or flight condition.
``Sustained forces,'' on the other hand, are those control forces
resulting from normal or failure conditions that cannot readily be
trimmed out or eliminated. The FAA proposed adding these definitions of
``transient'' and ``sustained'' forces to AC 25-7.
In addition, the FAA proposed several minor editorial changes for
Secs. 25.143(c) through 25.143(e) to improve readability and correct
grammatical errors. For example, the words ``immediately preceding''
were proposed to replace ``next preceding'' in Sec. 25.143(d). These
editorial changes were intended only to clarify the regulatory
language, while retaining the existing interpretation of the affected
sections.
Proposal 3. The FAA proposed to add the JAR 25.143(f) requirements
regarding control force characteristics during maneuvering flight to
part 25 as a new Sec. 25.143(f). By adding these requirements, the FAA
would ensure that the force to move the control column, or ``stick,''
must not be so great as to make excessive demands on the pilot's
strength when maneuvering the airplane, and must not be so low that the
airplane can easily be overstressed inadvertently.
These harmonized requirements would apply up to the speed VFC/
MFC (the maximum speed for stability characteristics) rather than
the speed VMC/MMC (the maximum operating limit speed)
specified by the current JAR 25.143(f). Requiring these maneuvering
requirements to be met up to VFC/MFC is consistent with other
part 25 stability requirements. Section 25.253, which defines VFC/
MFC, would be revised to reference the use of this speed in the
proposed Sec. 25.143(f). An acceptable means of compliance with
Sec. 25.143(f), including detailed interpretations of the stick force
characteristics that meet these requirements, would be added to AC 25-
7.
Proposal 4. Section 25.149(f) requires that the minimum control
speed be determined assuming the critical engine suddenly fails during
(or just prior to) a go-around from an all-engines-operating approach.
For airplanes with [[Page 30746]] three or more engines, Sec. 25.149(g)
requires the minimum control speed to be determined for a one-engine-
inoperative landing approach in which a second critical engine suddenly
fails. The FAA proposed to revise Secs. 25.149(f) through 25.149(h) to
clarify and revise the criteria for establishing these minimum control
speeds, VMCL and VMCL-2, respectively, for use during
approach and landing.
The FAA proposed to clarify that VMCL and VMCL-2 apply
not only to the airplane's approach configuration(s), as prescribed in
the current standards, but also to the landing configuration(s). The
FAA recognizes that configuration changes occur during approach and
landing (e.g. flap setting and landing gear position) and considers
that the minimum control speeds provided in the AFM should ensure
airplane controllability, following a sudden engine failure, throughout
the approach and landing.
Applicants would have the option of determining VMCL and
VMCL-2 either for the most critical of the approach and landing
configurations (i.e., the configuration resulting in the highest
minimum control speed), or for each configuration used for approach or
for landing. By determining the minimum control speeds in the most
critical configuration, applicants would not be required to conduct any
additional testing to that already required by the current standards.
Only if these resulting speeds proved too constraining for other
configurations would the FAA expect applicants to exercise the option
of testing multiple configurations.
The FAA also proposed to add provisions to state the position of
the propeller, for propeller airplanes, when establishing these minimum
control speeds. For the critical engine that is suddenly made
inoperative, the propeller position must reflect the most critical mode
of powerplant failure with respect to controllability, as required by
Sec. 25.149(a). Also, since credit cannot be given for pilot action to
feather the propeller during this high flightcrew workload phase of
flight, the FAA proposed that VMCL and VMCL-2 be determined
with the propeller position of the most critical engine in the position
it automatically achieves. For MCL-2, the engine that is already
inoperative before beginning the approach may be feathered, since the
pilot is expected to ensure the propeller is feathered before
initiating the approach.
To ensure that airplanes have adequate lateral control capability
at VMCL and VMCL-2, the FAA proposed to require airplanes to
be capable of rolling, from an initial condition of steady straight
flight, through an angle of 20 degrees in not more than 5 seconds, in
the direction necessary to start a turn away from the inoperative
engine. This proposed addition to Sec. 25.149 is contained in the
current JAR 25.149.
The FAA also proposed guidance material for AC 25-7 to enable
applicants to additionally determine the appropriate minimum control
speeds for an approach and landing in which one engine, and, for
airplanes with three or more engines, two engines, are already
inoperative prior to beginning the approach. These speeds, VMCL(1
out) and VMCL-2(2 out), would be less restrictive than VMCL
and VMCL-2 because the pilot is assumed to have trimmed the
airplane for the approach with an inoperative engine (for VMCL(1
out)) or two inoperative engines (for VMCL-2(2 out)). Also, the
approach and landing procedures under these circumstances may use
different approach and landing flaps than for the situations defining
VMCL or VMCL-2. These additional speeds could be used as
guidance in determining the recommended procedures and speeds for a
one-engine-inoperative, or, in the case of an airplane with three or
more engines, a two-engine-inoperative approach and landing.
The FAA proposed to revise Sec. 25.125 to require the approach
speed used for determining the landing distance to be equal to or
greater than VMCL, the minimum control speed for approach and
landing with all-engines-operating. This provision would ensure that
the speeds used for normal landing approaches with all-engines-
operating would provide satisfactory controllability in the event of a
sudden engine failure during, or just prior to, a go-around.
Proposal 5. The FAA proposed to revise the stall demonstration
requirements of Sec. 25.201 to clarify the airplane configurations and
procedures used in flight tests to demonstrate stall speeds and stall
handling characteristics. The list of acceptable flight characteristics
used to define the occurrence of stall would also be revised. To be
consistent with current practice, Sec. 25.201(b)(1) would require that
stall demonstrations also be conducted with deceleration devices (e.g.,
speed brakes) deployed. Additionally, the FAA proposed clarifying the
intent of Sec. 25.201(b) to cover normal, rather than failure,
conditions by requiring that stalls need only be demonstrated for the
approved configurations.
Section 25.201(c) would be revised to more accurately describe the
procedures used for demonstrating stall handling characteristics. The
cross-reference to Sec. 25.103(b), currently contained in
Sec. 25.201(c)(1), would be moved to a new Sec. 25.201(b)(4) for
editorial clarity and harmony with the JAR-25 format. Reference to the
pitch control reaching the aft stop, which would be interpreted as one
of the indications that the airplane has stalled, would be moved from
Sec. 25.201(c)(1) to Sec. 25.201(d)(3).
The list of acceptable flight characteristics that define the
occurrence of a stall, used during the flight tests demonstrating
compliance with the stall requirements, is provided in Sec. 25.201(d).
The FAA proposed to revise this list to conform with current practices.
Section 25.201(d)(1)(ii) would be removed to clarify that a rolling
motion, occurring by itself, is not considered an acceptable flight
characteristics for defining the occurrence of a stall. The proposed
Sec. 25.201(d)(2) would replace the criteria of Secs. 25.201(d)(1)(iii)
and 25.201(d)(2) because only deterrent buffeting (i.e., a distinctive
shaking of the airplane that is a strong and effective deterrent to
further speed reduction) is considered to comply with those criteria.
Finally, the proposed Sec. 25.201(d)(3) would define as a stall a
condition in which the airplane does not continue to pitch up after the
pitch control has been pulled back as far as it will go and held there
for a short period of time. Guidance material was proposed for AC 25-7
to define the length of time that the control stick must be held in
this full aft position when using Sec. 25.201(d)(3) to define a stall.
Proposal 6. Section 25.201 currently requires stalls to be
demonstrated at airspeed deceleration rates (i.e., entry rates) not
exceeding one knot per second. JAR 25.201 currently requires, in
addition, that turning flight stalls must be demonstrated at
accelerated rates of entry into the stall (i.e., dynamic stalls).
According to the JAA, the intended procedure for demonstrating dynamic
stalls begins with a 1 knot per second deceleration from the trim speed
(similar to normal stalls). Then, approximately halfway between the
trim speed and the stall warning speed, the flight test pilot applies
the elevator control to achieve an increase in the rate of change of
angle-of-attack. The final angle-of-attack rate and the control input
to achieve it should be appropriate to the type of airplane and its
particular control characteristics.
The AIA/AECMA petition detailed various difficulties with
interpretation of the JAR-25 requirement, noted that [[Page 30747]] the
requirement is not contained in the FAR, and proposed that dynamic
stalls be removed from JAR-25. Some of the concerns with the JAR-25
dynamic stall requirement include: (1) A significant number of flight
test demonstrations for compliance used inappropriate piloting
techniques considering the capabilities of transport category
airplanes; (2) the stated test procedures depend, to a large extent, on
pilot interpretation, resulting in test demonstrations that could vary
significantly for different test pilots; (3) the safety objective of
the requirement is not well understood within the aviation community;
and (4) the flight test procedures that are provided are inconsistent
with the flight characteristics being evaluated. As a result,
applicants are unable to ensure that their designs will comply with the
JAR-25 dynamic stall requirement prior to the certification flight
test.
In practice, FAA certification testing has typically included stall
demonstrations at entry rates higher than 1 knot per second. For
airplanes with certain special features, such as systems designed to
prevent a stall or that are needed to provide an acceptable stall
indication, higher entry rates are demonstrated to show that the system
will continue to safely perform its intended function under such
conditions. These higher entry rate stalls are different, however, from
the JAR-25 dynamic stalls.
Rather than simply deleting the dynamic stall requirements from
JAR-25, or adding this requirement to part 25, the ARAC recommended
harmonizing the two standards by requiring turning flight stalls be
demonstrated at steady airspeed deceleration rates up to 3 knots per
second. The FAA agrees with this recommendation and proposed to add the
requirement for a higher entry rate stall demonstration to part 25 as
Sec. 25.201(c)(2). The current Sec. 25.201(c)(2) would be redesignated
Sec. 25.201(c)(3). The JAA would replace the JAR-25 dynamic stall
requirement with the ARAC recommendation.
The proposed higher entry rate stall demonstration is a controlled
and repeatable maneuver that meets the objective of evaluating stall
characteristics over a range of entry conditions that might reasonably
be encountered by transport category airplanes in operational service.
Some degradation in characteristics would be accepted at the higher
entry rates, as long as it does not present a major threat to recovery
from the point at which the pilot has recognized the stall. Guidance
material was proposed for AC 25-7 to point out that the specified
deceleration rate, and associated rate of increase in angle of attack,
should be established from the trim speed specified in
Sec. 25.103(b)(1) and maintained up to the point at which the airplane
stalls.
The FAA proposed to revise Sec. 25.203(c) to specify a bank angle
that must not be exceeded during the recovery from the turning flight
stall demonstrations. Currently, Sec. 25.203(c) provides only a
qualitative statement that a prompt recovery must be easily attainable
using normal piloting skill. By specifying a maximum bank angle limit,
the FAA proposed to augment this qualitative requirement with a
quantitative one.
For deceleration rates up to 1 knot per second, the maximum bank
angle would be approximately 60 degrees in the original direction of
the turn, or 30 degrees in the opposite direction. These bank angle
limits are currently contained in JAR-25 guidance material, and have
been used informally during FAA certification programs as well. For
deceleration rates higher than 1 knot per second, the FAA proposed to
allow a greater maximum bank angle--approximately 90 degrees in the
original direction of the turn, or 60 degrees in the opposite
direction. These are the same acceptance criteria currently used by the
JAA to evaluate dynamic stall demonstrations.
In addition to the amendments to part 25 adopted by this final
rule, AC 25-7 is being revised to ensure that these harmonized
standards will be interpreted and applied consistently. AC 25-7
provides guidelines that the FAA has found acceptable regarding flight
testing transport category airplanes to demonstrate compliance with the
applicable airworthiness requirements. The changes to AC 25-7 are
described in a separate notice published elsewhere in this issue of the
Federal Register. Copies of the affected pages will be available for
distribution shortly after publication of this final rule.
Discussion of the Comments
Five commenters responded to the request for comments contained in
NPRM 94-15. All five commenters support the proposals, with two of the
commenters requesting that the FAA and JAA concurrently adopt the
proposed amendments soon. One of the commenters supports the proposals
as long as they apply only to future airplane certification programs,
and not to existing fleets.
The FAA appreciates the widespread support for these proposals,
which the FAA attributes to the use of the ARAC process. As a result of
this support, the FAA is adopting the proposed rules with only a few
minor clarifying changes. These changes, which do not affect the
intended application of the requirements, were made to prevent any
confusion that may have resulted from the proposed wording.
In Sec. 25.125(a)(2), the FAA has added the words ``whichever is
greater'' in reference to the two constraints on the stabilized
approach speed used to determine the landing distance. This addition
provides consistency with other sections of part 25 containing multiple
constraints, and clarifies that the more critical of the two
constraints must be satisfied.
In Sec. 25.143(c), the FAA proposed to replace the term
``temporary'' with the term ``transient'' to refer to those control
forces that the pilot is assumed to take immediate action to reduce or
eliminate. Examples of such forces are those resulting from raising or
lowering the flaps or landing gear, changing altitude or speed, or
recovering from some type of failure. The intended requirement relates
to the initial stabilized force resulting from these events, not to any
force peaks that may occur instantaneously. The term ``transient,''
however, could too easily be misinterpreted to refer to an
instantaneous peaking of the force level. Therefore, the FAA is
replacing ``temporary'' with ``short term'' rather than ``transient''
in Sec. 25.143(c). For consistent terminology, the FAA is also
replacing the term ``prolonged'' in Sec. 25.143(c) with ``long term.''
These changes are carried through to the other sections of the proposal
in which the terms ``temporary'' and ``prolonged'' appear
(Secs. 25.143(d) and (e) and 25.145(b)). The accompanying advisory
material that was proposed for AC 25-7 will also be revised
accordingly.
Due to a comment on the revisions proposed for AC 25-7 associated
with the proposed rule changes, the FAA finds it necessary to clarify
the requirements for the position of the propeller on the engine
suddenly made inoperative during the VMCL and VMCL-2
determination of Secs. 25.149(f) and 25.149(g). A windmilling propeller
creates significantly more drag than a feathered propeller, and hence
is the more critical position relative to maintaining control of the
airplane after an engine failure. Since Sec. 25.149(a) requires
VMCL and VMCL-2 to be determined using the most critical mode
of powerplant failure with respect to controllability, the windmilling
position must be assumed. Subsequent feathering of the propeller would
be accomplished either by an automatic system that
[[Page 30748]] senses the engine failure or by the pilot manually
adjusting the cockpit controls.
The requirements proposed in NPRM 94-15 would allow the propeller
to be in the feathered position if the propeller feathering is done
automatically. Credit for pilot action to manually feather the
propeller would be inappropriate during this high workload phase of
flight. Because an autofeather system may not be designed to respond to
an engine failure at low power settings, one commenter proposes adding
a statement to the advisory material in AC 25-7 to state that the
engine failure could be assumed to occur after the pilot sets go-around
power. The commenter's proposal would ensure that automatic propeller
feathering could be taken into account in determining VMCL and
VMCL-2, even if the automatic feathering would not occur for
engine failures at low power settings.
The FAA does not concur with the commenter's proposal. As was noted
in the NPRM 94-15 preamble discussion, VMCL and VMCL-2 must
be determined assuming the critical engine suddenly fails during, or
just prior to, the go-around maneuver. A sudden engine failure during
an approach for landing may be the reason for initiating the go-around.
If the autofeather system does not feather the propeller in this
situation, the minimum control speeds should not assume the propeller
is feathered.
To clarify this point, Secs. 25.149(f)(5) and 25.149(g)(5) have
been revised to state that the engine failure must be assumed to occur
from the power setting associated with maintaining a three degree
approach path angle. The revised wording also clarifies that these
provisions apply only to propeller airplanes. The word
``automatically,'' referring to the position achieved by the propeller,
has been replaced with ``without pilot action.'' This revision further
clarifies the intent of the requirement and is more appropriate
terminology for applying these requirements to airplanes lacking an
autofeather system.
The FAA is clarifying Sec. 25.201(d)(1) by removing the reference
to rolling motion. Section 25.201(d) defines and lists the airplane
behavior that gives the pilot a clear indication that the airplane has
stalled. The presence of rolling motion is immaterial to determining
whether or not the airplane has stalled. The proposed wording had been
intended to emphasize that a rolling motion by itself would be
unacceptable as a stall indication, and that any rolling motion that
did occur must be within the bounds allowed by Secs. 25.203 (b) and
(c); however, the FAA has decided that this explanatory material would
be better placed in AC 25-7.
With the exceptions noted above, the FAA is revising parts 1 and 25
as proposed. These amendments apply only to airplanes for which an
application for a new (or amended or supplemental, if applicable) type
certificate is made after the date the amendment becomes effective.
Regulatory Evaluation Summary
Final Regulatory Evaluation, Final Regulatory Flexibility
Determination, and Trade Impact Assessment
Three principal requirements pertain to the economic impacts of
changes to the Federal Aviation Regulations. First, Executive Order
12866 directs Federal agencies to promulgate new regulations or modify
existing regulations only if the expected benefits to society outweigh
the expected costs. Second, the Regulatory Flexibility Act of 1980
requires agencies to analyze the economic impact of regulatory changes
on small entities. Finally, the Office of Management and Budget directs
agencies to assess the effect of regulatory changes on international
trade. In conducting these analyses, the FAA has determined that this
rule: (1) Will generate benefits exceeding costs; (2) is not
``significant'' as defined in the Executive Order and the Department of
Transportation's (DOT) policies and procedures; (3) will not have a
significant impact on a substantial number of small entities; and (4)
will lessen restraints on international trade. These analyses,
available in the docket, are summarized below.
Cost Benefit Analysis
Three of the 48 provisions will require additional flight testing
and engineering analysis, resulting in compliance costs of $18,500 per
type-certification, or about $37 per airplane when amortized over a
representative production run of 500 airplanes. The primary benefits of
the rule are harmonization of flight test airworthiness standards with
the European Joint Aviation Requirements and clarification of existing
standards. The resulting increased uniformity of flight test standards
will simplify airworthiness approvals and reduce over flight testing
costs. While not readily quantifiable, these benefits will far exceed
the incremental costs of the rule.
Regulatory Flexibility Determination
The Regulatory Flexibility Act of 1980 (RFA) was enacted by
Congress to ensure that small entities are not unnecessarily or
disproportionately burdened by Federal regulations. The RFA requires a
Regulatory Flexibility Analysis if a rule will have a significant
economic impact, either detrimental or beneficial, on a substantial
number of small entities. FAA Order 2100.14A, Regulatory Flexibility
Criteria and Guidance, prescribes standards for complying with RFA
review requirements in FAA rulemaking actions. The Order defines
``small entities'' in terms of size thresholds, ``significant economic
impact'' in terms of annualized cost thresholds, and ``substantial
number'' as a number which is not less than eleven and which is more
than one-third of the small entities subject to the proposed or final
rule.
The rule will affect manufacturers of transport category airplanes
produced under future new airplane type certifications. For
manufacturers, Order 2100.14A specifies a size threshold for
classification as a small entity as 75 or fewer employees. Since no
part 25 airplane manufacturer has 75 or fewer employees, the rule will
not have a significant economic impact on a substantial number of small
airplane manufacturers.
Trade Impact Assessment
This final rule will not constitute a barrier to international
trade, including the export of American airplanes to foreign countries,
and the import of foreign airplanes into the United States. Instead,
the flight testing standards have been harmonized with those of foreign
aviation authorities, thereby lessening restraints on trade.
Federalism Implications
This final rule will not have substantial direct effects on the
States, on the relationship between the national government and the
State, or on the distribution of power and responsibilities among the
various levels of government. Therefore, in accordance with Executive
Order 12612, it is determined that this final rule will not have
sufficient federalism implications to warrant preparing a Federalism
Assessment.
Conclusion
Because the changes to standardize specific flight requirements of
part 25 of the FAR are not expected to result in substantial economic
cost, the FAA has determined that this regulation is not significant
under Executive Order 12866. Because this is an issue that has not
prompted a great deal of public concern, the FAA has determined that
this action is not significant under DOT [[Page 30749]] Regulatory
Policies and Procedures (44 FR 11034, February 25, 1979). In addition,
since there are no small entities affected by this rulemaking, the FAA
certifies, under the criteria of the Regulatory Flexibility Act, that
this regulation will not have a significant economic impact, positive
or negative, on a substantial number of small entities. A copy of the
regulatory evaluation prepared for this regulation has been placed in
the public docket. A copy may be obtained by contacting the person
identified under the caption, FOR FURTHER INFORMATION CONTACT.
List of Subjects
14 CFR Part 1
Air transportation.
14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
Adoption of the Amendment
In consideration of the foregoing, the Federal Aviation
Administration (FAA) amends 14 CFR parts 1 and 25 of the Federal
Aviation Regulations (FAR) as follows:
PART 1--DEFINITIONS AND ABBREVIATIONS
1. The authority citation for part 1 continues to read as follows:
Authority: 49 U.S.C. app. 1347, 1348, 1354(a), 1357(d)(2), 1372,
1421 through 1430, 1432, 1442, 1443, 1472, 1510, 1522, 1652(e),
1655(c), 1657(f), and 49 U.S.C. 106(g).
2. Section 1.1 is amended by adding a new definition to read as
follows:
Sec. 1.1 General definitions.
* * * * *
Go-around power or thrust setting means the maximum allowable in-
flight power or thrust setting identified in the performance data.
* * * * *
PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES
3. The authority citation for part 25 continues to read as follows:
Authority: 49 U.S.C. app. 1344, 1354(a), 1355, 1421, 1423, 1424,
1425, 1428, 1429, 1430; 49 U.S.C. 106(g); and 49 CFR 1.47(a).
4. Section 25.119 is amended by revising paragraph (a) to read as
follows:
Sec. 25.119 Landing climb: All-engines-operating.
* * * * *
(a) The engines at the power or thrust that is available eight
seconds after initiation of movement of the power or thrust controls
from the minimum flight idle to the go-around power or thrust setting;
and
* * * * *
5. Section 25.121 is amended by revising paragraph (d)(1) to read
as follows:
Sec. 25.121 Climb: One-engine-inoperative.
* * * * *
(d) * * *
(1) The critical engine inoperative, the remaining engines at the
go-around power or thrust setting;
* * * * *
6. Section 25.125 is amended by revising paragraph (a)(2) to read
as follows:
Sec. 25.125 Landing.
* * * * *
(a) * * *
(2) A stabilized approach, with a calibrated airspeed of not less
than 1.3 VS or VMCL, whichever is greater, must be maintained
down to the 50 foot height.
* * * * *
7. Section 25.143 is amended by revising paragraphs (c), (d), and
(e) and adding a new paragraph (f) to read as follows:
Sec. 25.143 General.
* * * * *
(c) The following table prescribes, for conventional wheel type
controls, the maximum control forces permitted during the testing
required by paragraphs (a) and (b) of this section:
------------------------------------------------------------------------
Force, in pounds, applied to the control
wheel or rudder pedals Pitch Roll Yaw
------------------------------------------------------------------------
For short term application for pitch and roll
control--two hands available for control.... 75 50 .......
For short term application for pitch and roll
control--one hand available for control..... 50 25 .......
For short term application for yaw control... ....... ....... 150
For long term application.................... 10 5 20
------------------------------------------------------------------------
(d) Approved operating procedures or conventional operating
practices must be followed when demonstrating compliance with the
control force limitations for short term application that are
prescribed in paragraph (c) of this section. The airplane must be in
trim, or as near to being in trim as practical, in the immediately
preceding steady flight condition. For the takeoff condition, the
airplane must be trimmed according to the approved operating
procedures.
(e) When demonstrating compliance with the control force
limitations for long term application that are prescribed in paragraph
(c) of this section, the airplane must be in trim, or as near to being
in trim as practical.
(f) When maneuvering at a constant airspeed or Mach number (up to
VFC/MFC), the stick forces and the gradient of the stick
force versus maneuvering load factor must lie within satisfactory
limits. The stick forces must not be so great as to make excessive
demands on the pilot's strength when maneuvering the airplane, and must
not be so low that the airplane can easily be overstressed
inadvertently. Changes of gradient that occur with changes of load
factor must not cause undue difficulty in maintaining control of the
airplane, and local gradients must not be so low as to result in a
danger of overcontrolling.
8. Section 25.145 is amended by revising paragraphs (b)
introductory paragraph, (b)(3), (b)(4), and (c)(1) to read as follows:
Sec. 25.145 Longitudinal control.
* * * * *
(b) With the landing gear extended, no change in trim control, or
exertion of more than 50 pounds control force (representative of the
maximum short term force that can be applied readily by one hand) may
be required for the following maneuvers:
* * * * *
(3) Repeat paragraph (b)(2), except at the go-around power or
thrust setting.
(4) With power off, flaps retracted, and the airplane trimmed at
1.4 VSI, rapidly set go-around power or thrust while maintaining
the same airspeed.
* * * * *
(c) * * *
(1) Simultaneous movement of the power or thrust controls to the
go-around power or thrust setting;
* * * * *
9. Section 25.149 is amended by revising paragraphs (f), (g) and
(h) to read as follows:
Sec. 25.149 Minimum control speed.
* * * * *
(f) VMCL, the minimum control speed during approach and
landing with all engines operating, is the calibrated airspeed at
which, when the critical engine is suddenly made inoperative, it
[[Page 30750]] is possible to maintain control of the airplane with
that engine still inoperative, and maintain straight flight with an
angle of bank of not more than 5 degrees. VMCL must be established
with--
(1) The airplane in the most critical configuration (or, at the
option of the applicant, each configuration) for approach and landing
with all engines operating;
(2) The most unfavorable center of gravity;
(3) The airplane trimmed for approach with all engines operating;
(4) The most favorable weight, or, at the option of the applicant,
as a function of weight;
(5) For propeller airplanes, the propeller of the inoperative
engine in the position it achieves without pilot action, assuming the
engine fails while at the power or thrust necessary to maintain a three
degree approach path angle; and
(6) Go-around power or thrust setting on the operating engine(s).
(g) For airplanes with three or more engines, VMCL-2, the
minimum control speed during approach and landing with one critical
engine inoperative, is the calibrated airspeed at which, when a second
critical engine is suddenly made inoperative, it is possible to
maintain control of the airplane with both engines still inoperative,
and maintain straight flight with an angle of bank of not more than 5
degrees. VMCL-2 must be established with--
(1) The airplane in the most critical configuration (or, at the
option of the applicant, each configuration) for approach and landing
with one critical engine inoperative;
(2) The most unfavorable center of gravity;
(3) The airplane trimmed for approach with one critical engine
inoperative;
(4) The most unfavorable weight, or, at the option of the
applicant, as a function of weight;
(5) For propeller airplanes, the propeller of the more critical
inoperative engine in the position it achieves without pilot action,
assuming the engine fails while at the power or thrust necessary to
maintain a three degree approach path angle, and the propeller of the
other inoperative engine feathered;
(6) The power or thrust on the operating engine(s) necessary to
maintain an approach path angle of three degrees when one critical
engine is inoperative; and
(7) The power or thrust on the operating engine(s) rapidly changed,
immediately after the second critical engine is made inoperative, from
the power or thrust prescribed in paragraph (g)(6) of this section to--
(i) Minimum power or thrust; and
(ii) Go-around power or thrust setting.
(h) In demonstrations of VMCL and VMCL-2--
(1) The rudder force may not exceed 150 pounds;
(2) The airplane may not exhibit hazardous flight characteristics
or require exceptional piloting skill, alertness, or strength;
(3) Lateral control must be sufficient to roll the airplane, from
an initial condition of steady flight, through an angle of 20 degrees
in the direction necessary to initiate a turn away from the inoperative
engine(s), in not more than 5 seconds; and
(4) For propeller airplanes, hazardous flight characteristics must
not be exhibited due to any propeller position achieved when the engine
fails or during any likely subsequent movements of the engine or
propeller controls.
10. Section 25.201 is amended by revising paragraphs (b), (c), and
(d) to read as follows:
Sec. 25.201 Stall demonstration.
* * * * *
(b) In each condition required by paragraph (a) of this section, it
must be possible to meet the applicable requirements of Sec. 25.203
with--
(1) Flaps, landing gear, and deceleration devices in any likely
combination of positions approved for operation;
(2) Representative weights within the range for which certification
is requested;
(3) The most adverse center of gravity for recovery; and
(4) The airplane trimmed for straight flight at the speed
prescribed in Sec. 25.103(b)(1).
(c) The following procedures must be used to show compliance with
Sec. 25.203;
(1) Starting at a speed sufficiently above the stalling speed to
ensure that a steady rate of speed reduction can be established, apply
the longitudinal control so that the speed reduction does not exceed
one knot per second until the airplane is stalled.
(2) In addition, for turning flight stalls, apply the longitudinal
control to achieve airspeed deceleration rates up to 3 knots per
second.
(3) As soon as the airplane is stalled, recover by normal recovery
techniques.
(d) The airplane is considered stalled when the behavior of the
airplane gives the pilot a clear and distinctive indication of an
acceptable nature that the airplane is stalled. Acceptable indications
of a stall, occurring either individually or in combination, are--
(1) A nose-down pitch that cannot be readily arrested;
(2) Buffeting, of a magnitude and severity that is a strong and
effective deterrent to further speed reduction; or
(3) The pitch control reaches the aft stop and no further increase
in pitch attitude occurs when the control is held full aft for a short
time before recovery is initiated.
11. Section 25.203 is amended by revising paragraph (c) to read as
follows:
Sec. 25.203 Stall characteristics.
* * * * *
(c) For turning flight stalls, the action of the airplane after the
stall may not be so violent or extreme as to make it difficult, with
normal piloting skill, to effect a prompt recovery and to regain
control of the airplane. The maximum bank angle that occurs during the
recovery may not exceed--
(1) Approximately 60 degrees in the original direction of the turn,
or 30 degrees in the opposite direction, for deceleration rates up to 1
knot per second; and
(2) Approximately 90 degrees in the original direction of the turn,
or 60 degrees in the opposite direction, for deceleration rates in
excess of 1 knot per second.
12. Section 25.253 is amended by revising paragraph (b) to read as
follows:
Sec. 25.253 High-speed characteristics.
* * * * *
(b) Maximum speed for stability characteristics, VFC/MFC.
VFC/MFC is the maximum speed at which the requirements of
Secs. 25.143(f), 25.147(e), 25.175(b)(1), 25.177, and 25.181 must be
met with flaps and landing gear retracted. It may not be less than a
speed midway between VMO/MMO and VDF/MDF, except
that for altitudes where Mach number is the limiting factor, MFC
need not exceed the Mach number at which effective speed warning
occurs.
Issued in Washington, D.C. on June 2, 1995.
David R. Hinson,
Administrator.
[FR Doc. 95-14171 Filed 6-8-95; 8:45 am]
BILLING CODE 4910-13-M
