[Federal Register Volume 61, Number 119 (Wednesday, June 19, 1996)]
[Rules and Regulations]
[Pages 31324-31329]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-14083]




[[Page 31323]]


_______________________________________________________________________

Part IV





Department of Transportation





_______________________________________________________________________



Federal Aviation Administration



_______________________________________________________________________



14 CFR Parts 1 and 33



Airworthiness Standards: Aircraft Engines New One-Engine-Inoperative 
(EOI) Ratings, Definitions and Type Certification Standards; Final Rule

  Federal Register / Vol. 61, No. 119 / Wednesday, June 19, 1996 / 
Rules and Regulations  

[[Page 31324]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 1 and 33

[Docket No. 26019; Amendment Nos. 1-46, 33-18]
RIN 2120-AD21


Airworthiness Standards: Aircraft Engines New One-Engine-
Inoperative (OEI) Ratings, Definitions and Type Certification Standards

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment establishes definitions for new one-engine 
inoperative (OEI) ratings, and type certification standards for those 
ratings. This amendment is the result of a petition for rulemaking from 
Aerospace Industries Association of America, Inc. (AIA), and a 
recognition by both the FAA, along with other civil airworthiness 
authorities, and the aviation industry for a need for additional OEI 
power rating standards. The maximum engine power rating for rotorcraft 
available under current certification standards contained in the 
Federal Aviation Regulations (FAR's) is the 2\1/2\-minute OEI rating. 
This amendment establishes definitions and type certification standards 
for the 30-second OEI and 2-minute OEI rating at higher power levels 
than currently available. These new ratings will enhance rotorcraft 
safety after an engine failure or precautionary shutdown by providing 
the availability for higher OEI power. The benefits from this amendment 
are enhanced safety through improved rotorcraft takeoff and landing 
performances, and shorter field operations or higher payload with the 
same degree of safety.

EFFECTIVE DATE: August 19, 1996.

FOR FURTHER INFORMATION CONTACT:
Chung C. Hsieh, Aerospace Engineer, Engine and Propeller Standards 
Staff, ANE-110, Engine and Propeller Directorate, Aircraft 
Certification Service, FAA, 12 New England Executive Park, Burlington, 
MA 01803-5229, telephone (617) 238-7115; fax (617) 238-7199.

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a Notice of Proposed Rulemaking (NPRM) No. 89-27 
that was published in the Federal Register on September 22, 1989 (54 FR 
39080), and also issued Supplemental Notice of Proposed Rulemaking 
(SNPRM) No. 89-27A that was published in the Federal Register on 
February 7, 1995 (60 FR 7380). These notices proposed to define new 
one-engine inoperative (OEI) ratings for rotorcraft engines and 
establish type certification standards for these new OEI ratings. The 
new OEI ratings will be applicable to turbine engines installed on 
multiengine powered rotorcraft.
    The payload for multiengine rotorcraft is limited by the power 
available from the remaining operating engine(s) in the event one 
engine fails during takeoff or landing. Currently, the maximum engine 
power rating available for rotorcraft under part 33 is the 2\1/2\ OEI 
rating. This amendment establishes 30-second OEI and 2-minute OEI 
ratings at higher power level than currently available. The new rating 
will allow rotorcraft to carry higher payloads from existing fields or 
to takeoff from smaller fields with current payloads, without 
decreasing the level of safety for these operations. Engine type 
certification using these new ratings, however, as with other OEI 
ratings, remains optional.
    The Aerospace Industries Association of America, Inc., (AIA) 
submitted a petition for rulemaking to the FAA on September 20, 1984, 
requesting an amendment of the FAR's to permit type certification of 
engines and rotorcraft with new OEI ratings. The FAA acknowledged 
receipt of the AIA petition, by letter on November 26, 1984, and issued 
a notice of that petition that was published in the Federal Register on 
December 10, 1984 (49 FR 48759). The FAA subsequently held the petition 
in abeyance pending AIA's submission of a revised petition for 
rulemaking on April 1, 1987.
    The AIA then sponsored a meeting with the Association European des 
Constructeurs de Materiel d'Aerospatial (AECMA), the European 
Helicopter Association (EHA), and the European Joint Airworthiness 
Authorities (JAA) on April 9, 1987, and invited the FAA to attend. The 
purpose of this meeting was to familiarize the European community with 
the AIA petition. Thereafter, the FAA and the JAA convened their annual 
harmonization meeting on May 19-21, 1987, to discuss, in part, the 
status of programs of mutual interest. One result of the FAA/JAA 
meeting was a recommendation that the FAA and the JAA should strive to 
promulgate more harmonious rules and guidance material. Accordingly, 
the FAA coordinated their reviews of the AIA petition directly with the 
JAA. A meeting was held in late August 1987 between representatives of 
the FAA and the JAA to discuss the JAA's concerns with the AIA 
petition. The JAA provided many comments, most of which contained 
significant deviations from specifies of the petition being considered.
    On November 19, 1987, AIA, AECMA, and EHA jointly sponsored a 
meeting at AIA Headquarters in Washington, DC, and invited the FAA and 
the JAA to attend. The purpose of this meeting was for industry, AIA, 
AECMA, and EHA, to jointly address and respond to the comments and 
concerns previously expressed by the JAA. In follow-up to this meeting, 
on June 8, 1988, the AIA submitted additional revisions to their 
petition for rulemaking.
    The FAA then issued a final rule from a previous proposal amending 
parts 1 and 33 of the FAR's. Amendments 1-34 and 33-12 were issued and 
published in the Federal Register on September 2, 1988 (53 FR 34196, 
effective October 3, 1988), which redefined OEI ratings in part 1 and 
added the Continuous OEI rating in both part 1 and part 33.
    After reviewing the revised AIA petition, and coordinating with the 
JAA, the FAA issued NPRM No. 89-27 (54 FR 39080), to address the part 
33 engine certification aspects of 39-second and 2-minute OEI ratings, 
and NPRM No. 89-26 (54 FR 39086), to address the part 27 and part 29 
rotorcraft certification aspects of the OEI ratings. Both NPRM's were 
published in the Federal Register on September 22, 1989. During the 
comment period, the FAA held a joint public meeting to discuss the 
proposals of both NPRM's in Fort Worth, Texas, on November 16, 1989 
(see Notice of public meeting published on October 13, 1989, 54 FR 
41986). The Final rules to part 27 and part 29 were published in the 
Federal Register on September 16, 1994 (59 FR 47764).
    Based on the comments received, the FAA determined that the 
proposals contained in NPRM 89-27 warranted further consideration. 
Substantive changes were made to the proposed rule, and SNPRM 89-27A 
was published in the Federal Register on February 7, 1995 (60 FR 7380). 
The SNPRM gave all interested parties an opportunity to comment on the 
modified proposed rule.
    All interested persons have been given an opportunity to 
participate in this rulemaking, and due consideration has been given to 
all matters presented. Some minor editorial changes have been made to 
clarify the proposals as indicated herein. The changes are based on 
comments received and further FAA review of the proposals. The FAA has 
determined that certain technical issues associated with proposed 
revisions to Sec. 33.27 have not been resolved. These

[[Page 31325]]

technical issues will be discussed in an Aviation Rulemaking Advisory 
Committee (ARAC) working group (see Notice of establishment of 
Propulsion Harmonization Working Group at 57 FR 58840, December 11, 
1992). Except for the proposed revisions to Sec. 33.27 and other 
changes as indicated herein, the proposals contained in SNPRM 89-27A 
have been adopted without change.

Discussion of Comments

    The commenters represent domestic and foreign engine manufacturers, 
and foreign civil airworthiness authorities. Four commenters provided 
the FAA with comments to NPRM 89-27, addressing numerous issues. The 
FAA also received comments to SNPRM 89-27A from three commenters. This 
discussion addresses all the comments made to SNPRM 89-27A, plus those 
comments made to NPRM 89-27 that were not already addressed in the 
discussion section of SNPRM 89-27A. Some comments presented orally at 
the November 16, 1989, public meeting have not been addressed here, 
since they have been withdrawn; other oral comments were submitted in 
writing to the rules docket. The transcript of the public meeting is in 
the Rules Docket. The comments are grouped according to the applicable 
sections of the proposed amendment, with general comments discussed 
first.

General Comments

    One commenter recommends that the FAA should publish the proposals 
as worded in the SNPRM as a final rule for all applicable 14 CFR part 1 
and 33 sections, with the exception of the proposed revisions to 
Sec. 33.27.
    One commenter states that the new structure of helicopter engine 
ratings as proposed creates a new certification scheme for helicopters 
and, accordingly, all the pertinent regulatory and advisory matter must 
be considered at the same time. The commenter points out that guidance 
material for the proposed ratings, including the maintenance inspection 
requirements under Sec. 33.90 and on the issue of power assurance, is 
not available. Therefore, the commenter states that an acceptable level 
of safety cannot be achieved until all advisory and regulatory material 
can be reviewed at the same time.
    The FAA disagrees. Even though specific advisory material that 
addresses the new OEI ratings is not yet available, the FAA will not 
delay issuing this Final rule. The existing guidance material on the 
issue of power assurance, which is a certification requirement of the 
helicopter under Secs. 27.45(f) and 29.45(f), may be of assistance to 
applicants for type certification. A joint effort between the FAA's 
Engine & Propeller Directorate and the Rotorcraft Directorate, and both 
the engine and the helicopter industry, has resulted in a report 
published by the Society of Automotive Engineers (SAE), Aerospace 
Information Report AIR4083, ``Helicopter Power Assurance,'' dated July 
13, 1989. Also, guidance material addressing the existing Sec. 33.90 is 
provided in FAA Advisory Circular (AC) AC 33-2B, ``Aircraft Engine Type 
Certification Handbook''. This AC will be revised to include guidance 
material on power assurance and mandatory maintenance requirements for 
the new OEI ratings following the adoption of this Final rule. The FAA 
plans to issue advisory material for these new OEI ratings as soon as 
practical.
    The commenter also states that this rulemaking is based on an 
assumption that the new OEI ratings will be used only during the 
takeoff and landing phases of flight. The commenter speculates that it 
would be possible that these new ratings be utilized under the 
``External Load Operations'' provisions of Sec. 133.45(e)(1). The 
commenter suggests that the Regulatory Evaluation section needs to 
address whether this assumption will be invalidated if the enhanced OEI 
performance is taken into account for other than takeoff and landing 
purposes.
    The FAA disagrees. While the proposed new OEI ratings are intended 
to be used only after the failure of one engine on a multiengine 
rotorcraft during takeoff, climb, or landing, it is entirely possible 
that these new ratings might be utilized to meet the provisions of 
current Sec. 133.45(e)(1), if the rotorcraft and the operator fulfill 
those criteria. Therefore, the Regulatory Evaluation does not depend on 
how the higher power levels associated with the new OEI ratings may be 
used in showing compliance with an existing regulation. In addition the 
commenter does not suggest any changes to the regulatory language of 
the proposed amendment to part 1 or part 33 to address that concern. 
These new ratings are intended to supplement the existing OEI rating 
structure for the type certification of engines and rotorcraft. 
Existing rotorcraft operating rules with respect to OEI conditions 
should not be impacted by the addition of the 30-second and the 2-
minute OEI ratings.

Section 1.1  Definitions

    One commenter recommends that the existing Sec. 1.1 definition of 
rated 30-minute OEI power should be amended to clarify that the period 
of use must not exceed a total of 30 minutes during any flight. The 
commenter further states that many authorities are aware of instances 
of misinterpretations, not precluded by Flight Manuals, whereby more 
than 30 minutes of 30-minute OEI power could have been accumulated 
during one flight. This commenter also recommends that the common 
aspects of all existing and proposed definitions of rated power/thrust 
be expressed in identical language to eliminate differences as much as 
possible.
    The FAA disagrees. The existing Sec. 1.1 definition of rated 30-
minute OEI power states that the engine power at this rating is limited 
in use to a period of not more than 30 minutes after the failure of one 
engine of a multiengine rotorcraft. The language used to define the new 
30-second OEI and 2-minute OEI ratings is consistent with this and 
other OEI definitions. The recommendations on the existing definitions 
of rated power and thrust are beyond the scope of this rulemaking. Such 
a change may be considered, however, as part of the Engine & Propeller 
Directorate's ongoing study on engine ratings.

Section 33.14  Start-Stop Cyclic Stress

    One commenter states that the proposal should also include a change 
to existing Sec. 33.14 that would exclude OEI ratings from the meaning 
of the term ``maximum rated power'' as it appears in Sec. 33.14. The 
commenter bases the need for this change on an interpretation of the 
existing Sec. 33.14 using the preambles to two previous amendments to 
the FAR's, both pre-dating the most recent changes to parts 1 and 33 
relating to OEI ratings. The commenter concludes that the suggested 
changes would make Sec. 33.14 more rational and provide clarity to 
promote consistent application. The commenter also states that 
Sec. 33.14 should address rotational speed operating limits and rotor 
temperatures in addition to rated powers/thrusts.
    The FAA disagrees. No changes to Sec. 33.14 were proposed in either 
NPRM No. 89-27 or SNPRM 89-27A. The FAA finds that the existing 
Sec. 33.14 is adequate to address the new 30-second OEI and 2-minute 
OEI ratings.

Section 33.27  Turbine, Compressor, Fan and Turbosupercharger Rotors

    Several commenters state that proposed revisions to Sec. 33.27, 
rotor integrity, are not consistent with the status of the discussions 
on rotor integrity requirements currently ongoing in an ARAC working 
group.
    The FAA agrees that proposed Sec. 33.27 is not harmonized with JAR-
E. The proposed revision to Sec. 33.27 has been

[[Page 31326]]

removed from the Final rule as the proposal has not been completely 
harmonized by the FAA (part 33) and the JAA (JAR-E). However, the FAA 
will consider additional amendments to Sec. 33.27, and ARAC 
harmonization is anticipated. In the interim the FAA will address each 
application for type certification that requests 30-second OEI and 2-
minute OEI ratings on a case by case basis.

Section 33.29  Instrument Connection

    One commenter states that Sec. 29.1305(a)(24) requires an 
indication to the pilot when the use of OEI rating begins and when the 
allowed time of this rating has expired, and the proposed 33.29(c)(1) 
should have consistent requirements.
    The FAA agrees. New Sec. 33.29(c)(1) is changed accordingly. In 
addition, new Sec. 33.29(c)(3) is changed to clarify the FAA's intent 
to require that each usage of a power level at one of the new OEI 
ratings is limited in duration. Therefore, for example, as the 
definition of the rating provides, 30-second OEI power is limited to 
three periods of use in any one flight following an engine failure, and 
each period of use is limited to no more than 30 seconds. Unused time 
from one period of use may not be accumulated for use during a 
subsequent period. Accordingly, new Sec. 33.29(c)(3) is changed to 
provide for a means to record each use and the duration of each use of 
power at each rating.

Section 33.85  Calibration Tests

    One commenter states that the reference in proposed Sec. 33.85(d) 
to Secs. 33.87(f) (1) through (8) should read Sec. 33.87, because 
paragraphs (1) through (8) of proposed Sec. 33.87(f) relate only to the 
new 30-second OEI and 2-minute OEI ratings where proposed Sec. 33.85(d) 
is also applicable to the 2\1/2\-minute OEI rating.
    The FAA disagrees. New Sec. 33.85(d) is intended for 30-second OEI 
and 2-minute OEI ratings only, and reference to the 2\1/2\-minute OEI 
rating was accidentally included in the SNPRM. Therefore, the reference 
to the 2\1/2\- minute OEI rating is removed from new Sec. 33.85(d).

Section 33.87  Endurance Test

    One commenter questions whether, during the additional endurance 
testing introduced by proposed Sec. 33.87 (f)(1) through (f)(8), at 
least 100 percent of 30-second OEI and 2-minute OEI rated powers must 
be produced during all such operations. The commenter states that it 
appears to be the intent because Sec. 33.87(a)(3) remains applicable to 
the proposed Sec. 33.87(f), yet the commenter states that 100 percent 
power may only be required for the first sequence of proposed 
Sec. 33.87(f), and not for all the sequences.
    The FAA disagrees. The 100 percent rule of Sec. 33.87(a)(3) applies 
to new Sec. 33.87(f) for all sequences; no exceptions are intended or 
implied.
    One commenter suggests the following for proposed Sec. 33.87 (f)(1) 
through (f)(8):
    1. The test sequence described by Sec. 33.87 (f)(1) through (f)(8) 
would be required to be repeated eight times for a total time of not 
less than 180 minutes and would be required to be conducted in a 
prescribed sequence and without stopping during the 180 minutes total 
test period.
    2. The sequence during which the length of the particular test 
condition defined by Sec. 33.87(f)(4) is increased to sixty-five 
minutes would need to be re-defined as: ``except that during the fourth 
or fifth test sequence this period shall be sixty-five minutes.''
    The FAA disagrees. The two hour supplementary test is to simulate a 
flight scenario using 30-second and 2-minute OEI ratings. After the 
initial 30-second and 2-minute applications to complete the takeoff or 
effect a rejected takeoff and the climb out to a safe altitude and 
airspeed, the engine is run at the 30-minute or continuous OEI rating 
power to maintain a safe altitude enroute and to complete a landing of 
the aircraft. The two hour cyclic test defined in this section 
demonstrates the ability of the engine to complete a safe flight with 
up to three applications of the 30-second and 2-minute OEI ratings 
during one flight. The proposed changes from the commenter are not 
supported by reasonable technical justification.

Section 33.88  Engine Overtemperature Test

    One commenter suggests that the words ``steady state'' be inserted 
before the words ``power-on r.p.m.'' in proposed Sec. 33.88(c). The 
commenter states that the words are necessary since the test is 
conducted at maximum steady state rpm limit rather than maximum 
transient rpm limit. In addition, the proposed change to ``steady 
state'' rpm limit and to the post test acceptance criteria is also 
applicable to engines not having automatic temperature limiting which 
are tested at 75  deg.F above the maximum temperature limit.
    The FAA disagrees. The overtemperature condition associated with 
usage of the 30-second OEI rating is normally expected from over-
fueling and consequently is accompanied by an excess rpm, not a steady 
state level associated with a non-overtemperature or a non-overboost 
condition.
    One commenter states that use of the words ``provides an exception 
from the existing requirements'' in the preamble for Proposal No. 10 of 
NPRM 89-27, published September 22, 1989, concerning proposed 
Sec. 33.88, could be misconstrued, and that it would have been better 
to state `` * * * provides for an alleviation from the rotational speed 
and the gas temperature prescribed by the existing requirements* * *.''
    The FAA disagrees. The commenter does not suggest any changes to 
proposed Sec. 33.88 and the editorial comment addresses the wording 
preference in the preamble only.
    One commenter states that the last sentence of proposed 
Sec. 33.88(c) should read as follows: ``Following this run, the turbine 
assembly may exceed serviceable limits, provided there is no evidence 
of imminent failure. The applicant may be required to show there is no 
evidence of imminent failure by analysis or test''. Another commenter 
states that current JAR-E has no direct equivalent to the 5 minute 
tests of either the existing Sec. 33.88 or proposed Sec. 33.88(a). 
Proposed Sec. 33.88 (b) and (c), which make provision for 5 minute or 4 
minute over-temperature test for 30-second OEI ratings, will be 
considered by the JAA as a possible basis for a revision to JAR-E. 
However, this will be in addition to complying with the existing 
turbine rotor overtemperature requirement of JAR-E, C4-6, paragraph 22. 
The commenter also suggests that proposed Sec. 33.88 (b) and (c) should 
include a requirement that the worst case intended flight profile must 
be assumed to include at least a further two applications of 30-second 
OEI power, each followed by an application of 2 minute OEI power for 
consistency of interpretation and compatibility with usage rational for 
these particular OEI ratings, as stated in the ``Background'' of NPRM 
89-27.
    The FAA disagrees. The intent of the post-test requirements is to 
assure that after the overtemperature test, the engine is suitable for 
continued service use to complete the worst case intended flight 
profile associated with the application of the 30-second OEI power 
rating. Although the worst case scenario may include at lease two 
additional applications of both 30-second OEI power and 2-minute OEI 
power, the last sentence of revised Sec. 33.88(b) and revised 
Sec. 33.88(c) will permit the FAA, on a case by case assessment, to 
apply the best engineering judgment for each given engine type design 
tested.

[[Page 31327]]

    Two commenters state that the FAA is proposing a certification 
standard for rotorcraft engines with a temperature limiter that differs 
from the standard for all other type engines. The commenters conclude 
that if a temperature limiter principle is acceptable for rotorcraft 
engines, it should also be acceptable for other gas turbine engines and 
for other engine ratings. Therefore, the proposal should be changed to 
apply generally and not just to 30-second and 2-minute OEI ratings.
    The FAA disagrees. The FAA considers that this comment is beyond 
the scope of this rulemaking, which addresses only certification 
standards for rotorcraft engines. The FAA may consider further 
rulemaking to revise Sec. 33.88 for other gas turbine engine 
certifications.
    One commenter states that the overtemperature subject has been 
incorporated into the harmonization effort and requests that the FAA 
clearly indicate the intent to harmonize certification standards 
related to overtemperature.
    The FAA agrees. The FAA will continue to support the ongoing 
harmonization effort toward the overtemperature test rule with the JAA 
through the ARAC. However, the proposed overtemperature test 
requirements in the SNPRM for 30-second and 2-minute OEI ratings are 
published as an addition to the existing rule based on the comments 
received. It is anticipated that the ARAC will recommend the adoption 
of the overtemperature test for these new ratings in their draft 
proposals.

Section 33.90  Initial Maintenance Inspection

    One commenter suggests that the interpretation of the current 
Sec. 33.90 needs to clearly define the requirements in that section for 
engines that incorporate the new OEI rated power levels, and that an 
advisory circular must be published together with this Final rule.
    The FAA disagrees. The FAA should not delay publication of this 
Final rule pending the development of new advisory material. The FAA 
plans to issue to the advisory material as soon as practical.

Section 33.93  Teardown Inspection

    One commenter states that in proposed Sec. 33.93, there is an 
``and'' which they believe should be an ``or'' in the first sentence of 
proposed Sec. 33.93(c), so that the fifth and sixth lines would read: 
``the endurance testing of Sec. 33.87 (b) or (c) or (d) or (e) or this 
part and followed * * *''. This change is needed because proposed 
33.87(a) states: ``for engines tested under paragraphs (b), (c), (d) or 
(e) of this section * * *'' and the new Sec. 33.87(f) reads: ``and 
following completion of the tests under paragraphs (b), (c), (d) or (e) 
of this section * * *''.
    The FAA agrees. The changes to revised Sec. 33.93 are made.

Regulatory Evaluation Summary

    Changes to the federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs Federal agencies to 
promulgate new regulations or modify existing regulations only if the 
potential benefits to society outweigh the potential 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 effects 
of regulatory changes on international trade. In conducting these 
assessments, the FAA has determined that this rule: (1) Will generate 
benefits exceeding its costs and is not ``significant'' as defined in 
Executive Order 12866; (2) is not ``significant'' as defined in DOT's 
Policies and Procedures; (3) will not have a significant impact on a 
substantial number of small entities; and (4) will not restrain 
international trade. These analyses are available in the docket.
    The new OEI power ratings will afford rotorcraft manufacturers the 
opportunity to install higher rated engines in their products. The 
principal operational benefits will be the ability to carry higher 
payloads from existing fields or to takeoff from smaller fields with 
current payloads, which should enable more Category B operators to use 
their rotorcraft for Category A operations, and also increase the 
potential for all operators to use more efficient and profitable 
routes.
    The testing costs associated with obtaining these ratings should be 
viewed as the price of an additional capability and would be evaluated 
by the manufacturer based on market potential. It is not possible to 
quantify the extent of the net operational benefits that will be 
realized by the operators because the number of products that will be 
certificated to this standard cannot be predicted. The FAA is able to 
conclude, however, that the rule will not have a negative economic 
impact on manufacturers or operators. Because these are optional 
ratings, manufacturers will provide this capability only if the 
additional costs can be recovered in the marketplace.
    Safety after an engine failure under the provisions of this rule 
will be as test equivalent to operational safety under the previous 
regulations. This assessment is based on the requirement for an engine 
inspection following one mission cycle of either the 30-second or 2-
minute OEI power levels. All engine parts that may not be suitable for 
further use must be discarded and replaced in order to maintain the 
continued airworthiness of the engine. The existing minimum level of 
engine airworthiness will be maintained under this rule by virtue of 
new and existing design, analysis, and test certification requirements. 
In summary, the FAA finds that the benefits of this rule will exceed 
the costs.

International Trade Impact Analysis

    These rule changes will have little or no impact on trade for both 
U.S. firms doing business in foreign countries and foreign firms doing 
business in the United States. In the U.S. market, foreign 
manufacturers will have the option of designing engines and helicopters 
capable of satisfying the new OEI ratings and therefore will not be at 
a competitive disadvantage with U.S. manufacturers. Because of the 
large U.S. market, foreign manufacturers are likely to certify their 
rotorcraft to U.S. rules, which will limit any competitive advantage 
U.S. manufacturers might gain in foreign markets.

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 Government regulations. The RFA requires 
a Regulatory Flexibility Analysis if a rule would 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, establishes threshold cost values and small 
entity size standards for complying with RFA review requirements in FAA 
rulemaking actions. A review of domestic engine manufacturers indicates 
that none meets the minimum size threshold. As such, the FAA has 
determined that this rule will not have significant economic impact on 
a substantial number of small entities.

Federalism Implications

    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and

[[Page 31328]]

responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
regulation does not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.

Conclusion

    For the reasons discussed in the preamble, and based on the 
findings in the Regulatory Flexibility Determination and the 
International Trade Impact Analysis, the FAA has determined that this 
regulation is not a significant regulatory action under Executive Order 
12866. In addition, the FAA certifies that these amendments do not have 
a significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. These amendments are considered nonsignificant under 
DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 
1979). A regulatory evaluation of the amendments, including a 
Regulatory Flexibility Determination and Trade Impact Analysis, has 
been placed in the docket. A copy may be obtained by contacting the 
person identified under FOR FURTHER INFORMATION CONTACT.

List of Subjects

14 CFR Part 1

    Airmen, Flights, Balloons, Parachutes, Aircraft Pilots, Pilots 
Transportation, Agreements, Kites, Air Safety, Safety, Aviation Safety, 
Air Transportation, Air Carriers, Aircraft, Airports, Airplanes, 
Helicopters, Rotorcraft, Heliports, Engines, Ratings.

14 CFR Part 33

    Engines, Rotorcraft, Air Transportation, Aircraft, Aviation safety, 
Safety.

Adoption of the Amendments

    Accordingly, The Federal Aviation Administration (FAA) amends 14 
CFR part 1 and part 33 as follows:

PART 1--DEFINITIONS AND ABBREVIATIONS

    1. The authority citation for part 1 continues to read as follows:

    Authority: 49 U.S.C 106(g), 40113, 44701.

    2. Section 1.1 is amended by adding the definitions in alphabetical 
order of ``Rated 30-Second OEI Power'' and ``Rated 2-Minute OEI Power'' 
to read as follows:


Sec. 1.1  General Definitions.

* * * * *
    Rated 30-second OEI power, with respect to rotorcraft turbine 
engines, means the approved brake horsepower developed under static 
conditions at specified altitudes and temperatures within the operating 
limitations established for the engine under part 33 of this chapter, 
for continued one-flight operation after the failure of one engine in 
multiengine rotorcraft, limited to three periods of use no longer than 
30 seconds each in any one flight, and followed by mandatory inspection 
and prescribed maintenance action.
    Rated 2-minute OEI power, with respect to rotorcraft turbine 
engines, means the approved brake horsepower developed under static 
conditions at specified altitudes and temperatures within the operating 
limitations established for the engine under part 33 of this chapter, 
for continued one-flight operation after the failure of one engine in 
multiengine rotorcraft, limited to three periods of use no longer than 
2 minutes each in any one flight, and followed by mandatory inspection 
and prescribed maintenance action.
* * * * *

PART 33--AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES

    3. The authority citation for part 33 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

    4. Section 33.7 is amended by redesignating paragraph (c)(1)(viii) 
as (c)(1)(x); by revising newly redesignated (c)(1)(x); and by adding 
new paragraphs (c)(1)(viii) and (c)(1)(ix) to read as follows:


Sec. 33.7  Engine ratings and operating limitations.

* * * * *
    (c) * * *
    (1) * * *
    (viii) Rated 2-minute OEI power;
    (ix) Rated 30-second OEI power; and
    (x) Auxiliary power unit (APU) mode of operation.
* * * * *
    5. Section 33.29 is amended by adding new paragraph (c) as follows:


Sec. 33.29  Instrument connection.

* * * * *
    (c) Each rotorcraft turbine engine having a 30-second OEI rating 
and a 2-minute OEI rating must have a provision for a means to:
    (1) Alert the pilot when the engine is at the 30-second OEI and the 
2-minute OEI power levels, when the event begins, and when the time 
interval expires;
    (2) Determine, in a positive manner, that the engine has been 
operated at each rating; and
    (3) Automatically record each usage and duration of power at each 
rating.
    6. Section 33.67 is amended by adding new paragraph (d) as follows:


Sec. 33.67  Fuel system.

* * * * *
    (d) Engines having a 30-second OEI rating must incorporate means 
for automatic availability and automatic control of a 30-second OEI 
power.
    7. Section 33.85 is amended by adding new paragraphs (c) and (d) as 
follows:


Sec. 33.85  Calibration tests.

* * * * *
    (c) In showing compliance with this section, each condition must 
stabilize before measurements are taken, except as permitted by 
paragraph (d) of this section.
    (d) In the case of engines having 30-second OEI, and 2-minute OEI 
ratings, measurements taken during the applicable endurance test 
prescribed in Sec. 33.87(f) (1) through (8) may be used in showing 
compliance with the requirements of this section for these OEI ratings.
    8. Section 33.87 is amended by revising the introductory text of 
paragraph (a) and paragraph (a)(8); by redesignating paragraph (f) as 
paragraph (g); by revising the reference ``(e)(2) (ii) through (iv)'' 
to read ``(g)(2) (ii) through (iv)'' in newly designated paragraph 
(g)(2)(i), by revising the reference ``(e)(2)(i)'' to read 
``(g)(2)(i)'' in newly designated paragraph ``(g)(2)(ii)''; by revising 
the reference ``(e)(2)(i)'' to read ``(g)(2)(i)'' in newly designated 
paragraph ``(g)(2)(iii)''; by revising the reference ``(e)(2) (i) and 
(ii)'' to read ``(g)(2) (i) and (ii)'' in newly designated paragraph 
(g)(2)(iv); and by adding a new paragraph (f) to read as follows:


Sec. 33.87  Endurance test.

    (a) General. Each engine must be subjected to an endurance test 
that includes a total of at least 150 hours of operation and, depending 
upon the type and contemplated use of the engine, consists of one of 
the series of runs specified in paragraphs (b) through (g) of this 
section, as applicable. For engines tested under paragraphs (b), (c), 
(d), (e) or (g) of this section, the prescribed 6-hour test sequence 
must be conducted 25 times to complete the required 150 hours of 
operation. Engines for which the 30-second OEI and 2-minute OEI ratings 
are desired must be further tested under paragraph

[[Page 31329]]

(f) of this section. The following test requirements apply:
* * * * *
    (8) If the number of occurrences of either transient rotor shaft 
overspeed or transient gas overtemperature is limited, that number of 
the accelerations required by paragraphs (b) through (g) of this 
section must be made at the limiting overspeed or overtemperature. If 
the number of occurrences is not limited, half the required 
accelerations must be made at the limiting overspeed or 
overtemperature.
* * * * *
    (f) Rotorcraft engines for which 30-second OEI and 2-minute OEI 
ratings are desired. For each rotorcraft engine for which 30-second OEI 
and 2-minute OEI power ratings are desired, and following completion of 
the tests under paragraphs (b), (c), (d), or (e) of this section, the 
applicant may disassemble the tested engine to the extent necessary to 
show compliance with the requirements of Sec. 33.93(a). The tested 
engine must then be reassembled using the same parts used during the 
test runs of paragraphs (b), (c), (d), or (e) of this section, except 
those parts described as consumables in the Instructions for Continued 
Airworthiness. The applicant must then conduct the following test 
sequence four times, for a total time of not less than 120 minutes:
    (1) Takeoff power. Three minutes at rated takeoff power.
    (2)30-second OEI power. Thirty seconds at rated 30-second OEI 
power.
    (3) 2-minute OEI power. Two minutes at rated 2-minute OEI power.
    (4) 30-minute OEI power, continuous OEI power, or maximum 
continuous power. Five minutes at rated 30-minute OEI power, rated 
continuous OEI power, or rated maximum continuous power, whichever is 
greatest, except that, during the first test sequence, this period 
shall be 65 minutes.
    (5) 50 percent takeoff power. One minute at 50 percent takeoff 
power.
    (6) 30-second OEI power. Thirty seconds at rated 30-second OEI 
power.
    (7) 2-minute OEI power. Two minutes at rated 2-minute OEI power.
    (8) Idle. One minute at idle.
* * * * *
    9. Section 33.88 is revised to read as follows:


Sec. 33.88  Engine overtemperature test.

    (a) Each engine must run for 5 minutes at maximum permissible rpm 
with the gas temperature at least 75  deg.F (42  deg.C) higher than the 
maximum rating's steady-state operating limit, excluding maximum values 
of rpm and gas temperature associated with the 30-second OEI and 2-
minute OEI ratings. Following this run, the turbine assembly must be 
within serviceable limits.
    (b) Each engine for which 30-second OEI and 2-minute OEI ratings 
are desired, that does not incorporate a means to limit temperature, 
must be run for a period of 5 minutes at the maximum power-on rpm with 
the gas temperature at least 75  deg.F (42  deg.C) higher than the 30-
second OEI rating operating limit. Following this run, the turbine 
assembly may exhibit distress beyond the limits for an overtemperature 
condition provided the engine is shown by analysis or test, as found 
necessary by the Administrator, to maintain the integrity of the 
turbine assembly.
    (c) Each engine for which 30-second OEI and 2-minute OEI ratings 
are desired, that incorporates a means to limit temperature, must be 
run for a period of 4 minutes at the maximum power-on rpm with the gas 
temperature at least 35  deg.F (20  deg.C) higher than the maximum 
operating limit. Following this run, the turbine assembly may exhibit 
distress beyond the limits for an overtemperature condition provided 
the engine is shown by analysis or test, as found necessary by the 
Administrator, to maintain the integrity of the turbine assembly.
    (d) A separate test vehicle may be used for each test condition.
    10. Section 33.93 is revised to read as follows:


Sec. 33.93  Teardown inspection.

    (a) After completing the endurance testing of Sec. 33.87 (b), (c), 
(d), (e), or (g) of this part, each engine must be completely 
disassembled, and
    (1) Each component having an adjustment setting and a functioning 
characteristic that can be established independent of installation on 
the engine must retain each setting and functioning characteristic 
within the limits that were established and recorded at the beginning 
of the test; and
    (2) Each engine part must conform to the type design and be 
eligible for incorporation into an engine for continued operation, in 
accordance with information submitted in compliance with Sec. 33.4.
    (b) After completing the endurance testing of Sec. 33.87(f), each 
engine must be completely disassembled, and
    (1) Each component having an adjustment setting and a functioning 
characteristic that can be established independent of installation on 
the engine must retain each setting and functioning characteristic 
within the limits that were established and recorded at the beginning 
of the test; and
    (2) Each engine may exhibit deterioration in excess of that 
permitted in paragraph (a)(2) of this section including some engine 
parts or components that may be unsuitable for further use. The 
applicant must show by analysis and/or test, as found necessary by the 
Administrator, that structural integrity of the engine including 
mounts, cases, bearing supports, shafts, and rotors, is maintained; or
    (c) In lieu of compliance with paragraph (b) of this section, each 
engine for which the 30-second OEI and 2-minute OEI ratings are 
desired, may be subjected to the endurance testing of Secs. 33.87 (b), 
(c), (d), or (e) of this part, and followed by the testing of 
Sec. 33.87(f) without intervening disassembly and inspection. However, 
the engine must comply with paragraph (a) of this section after 
completing the endurance testing of Sec. 33.87(f).

    Issued in Washington, DC, on May 30, 1996.
David R. Hinson,
Administrator.
[FR Doc. 96-14083 Filed 6-18-96; 8:45 am]
BILLING CODE 4910-13-M