Source: https://www.federalregister.gov/documents/2001/05/15/01-12103/airspeed-indicating-system-requirements-for-transport-category-airplanes
Timestamp: 2017-08-18 17:48:10
Document Index: 603737730

Matched Legal Cases: ['art 25', 'art 25', 'art 25', 'art 25', '§\u200925', '§\u200925', '§\u200925', 'art 25', 'art 25', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', '§\u200925', '§\u200925', 'art 25', '§\u200925', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', '§\u200925']

Federal Register :: Airspeed Indicating System Requirements for Transport Category Airplanes
Airspeed Indicating System Requirements for Transport Category Airplanes
66 FR 26947
26947-26953 (7 pages)
Docket No. FAA-2001-9636
2120-AH26
What Is the ARAC and What Role Does It Play in Harmonization?
What, If Any, Are the Differences in the Means of Compliance and How Have the Standards Been Applied?
What Is the Proposed Action and How Does it Address the Underlying Safety Issue?
https://www.federalregister.gov/d/01-12103 https://www.federalregister.gov/d/01-12103
The Federal Aviation Administration proposes to amend the airworthiness standards for transport category airplanes concerning the airspeed indicating system. This proposal would add airspeed indication requirements for speeds greater than and less than the speed range for which airspeed indication accuracy requirements currently apply, would add a requirement that airspeed indications not cause the pilot undue difficulty between the initiation of rotation and the achievement of a steady climbing condition during takeoff, and would also add a requirement to limit the effects of airspeed lag. Adopting this proposal would eliminate a regulatory difference between the airworthiness standards of the U.S. and the Joint Aviation Requirements of Europe, without affecting current industry design practices.
Address your comments to Dockets Management System, U.S. Department of Transportation Dockets, Room Plaza 401, 400 Seventh Street SW., Washington, DC 20590-0001. You must identify the docket number, FAA-2001-9636, at the beginning of your comments, and you should submit two copies of your comments. If you wish to receive confirmation that the FAA has received your comments, please include a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. FAA-2001-9636.” We will date-stamp the postcard and mail it back to you.
You may review the public docket containing comments on this proposed regulation at the Department of Transportation (DOT) Dockets Office, located on the plaza level of the Nassif Building at the above address. You may review the public docket in person at this address between 9:00 a.m. and 5:00 p.m., Monday through Friday, except Federal holidays. Also, you may review the public dockets on the Internet at http://dms.dot.gov.
Interested persons are invited to participate in the making of the proposed action by submitting such written data, views, or arguments as they may desire. Comments relating to the environmental, energy, federalism, or economic impact that might result from adopting the proposals in this document are also invited. Substantive comments should be accompanied by cost estimates. Comments must identify the regulatory docket number and be submitted in duplicate to the DOT Rules Docket address specified above.
Internet users may access recently published rulemaking documents at the FAA's web page at or the GPO's web page at http://www.faa.gov/​avr/​arm/​nprm/​nprm.htm or the GPO's web page at http://www.access.gpo.gov/​nara.
You may obtain a copy of this document by submitting a request to the Federal Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence Avenue SW., Washington, DC 20591; or by calling 202-267-9680. Communications must identify the docket number of this NPRM.
Although part 25 and JAR-25 are very similar, they are not identical in every respect. When airplanes are type certificated to both sets of standards, the differences between part 25 and JAR-25 can result in substantial additional costs Start Printed Page 26949to manufacturers and operators. These additional costs, however, frequently do not bring about an increase in safety. In many cases, part 25 and JAR-25 may contain different requirements to accomplish the same safety intent. Consequently, manufacturers are usually burdened with meeting the requirements of both sets of standards, although the level of safety is not increased correspondingly.
The FAA had formally established ARAC in 1991 (56 FR 2190, January 22, 1991) to provide advice and recommendations concerning the full range of the FAA's safety-related rulemaking activity. The FAA sought this advice to develop better rules in less overall time and using fewer FAA resources than previously needed. The committee provides the FAA firsthand information and insight from interested parties regarding potential new rules or revisions of existing rules.
In light of a general agreement among the affected industries and authorities to expedite the harmonization program, the FAA and JAA, in March 1999, agreed upon a method to achieve these goals. This method, which the FAA has titled “The Fast Track Harmonization Program,” is aimed at expediting the rulemaking process for harmonizing not only the 42 standards that are currently tasked to ARAC for harmonization, but approximately 80 additional standards for part 25 airplanes.
Under this program, the FAA provides ARAC with an opportunity to review, discuss, and comment on the FAA's draft NPRM. In the case of this rulemaking, ARAC suggested a few editorial changes, which have been incorporated into this NPRM.
This proposed regulation results from the recommendations of ARAC submitted under the FAA's Fast Track Harmonization Program. In this notice, the FAA proposes to amend the airspeed indicating system requirements of § 25.1323. Start Printed Page 26950
The underlying safety issue is to prevent hazardously misleading airspeed information from being presented to the flightcrew. To this end, § 25.1323 specifies the accuracy and calibration requirements and the speed ranges over which each airspeed system must be calibrated. In addition, each airspeed system must be designed and installed so as to minimize the possibility of malfunction by the entry of foreign material, by icing, or due to a collision with a bird.
The current text of 14 CFR 25.1323(c) is:
(c) The airspeed error of the installation, excluding the airspeed indicator instrument calibration error, may not exceed three percent or five knots, whichever is greater, throughout the speed range, from—
(1) VMO to 1.3 VS1 with flaps retracted; and
(2) 1.3 VS0 to VFE with flaps in the landing position.
The text of JAR-25.1323(c), Chg. 14, Orange Paper 96/1, is:
(c)(1)The airspeed error of the installation, excluding the airspeed indicator instrument calibration error, may not exceed three percent or five knots, whichever is greater, throughout the speed range, from—
(i) VMO to 1.3 VS1 with wing-flaps retracted; and
(ii) 1.3 VS0 to VFE with wing-flaps in the landing position.
(2) From 1.3 VS to stall warning speed the IAS must change perceptibly with CAS and in the same sense, and at speeds below stall warning speed the IAS must not change in an incorrect sense. (See ACJ 25.1323(c)(2).)
(3) From VMO to VMO+2/3 (VDF−VMO) the IAS must change perceptibly with CAS and in the same sense, and at higher speeds up to VDF the IAS must not change in an incorrect sense. (See ACJ 25.1323(c)(3).)
(4) There must be no indication of airspeed which would cause undue difficulty to the pilot during the take-off between the initiation of rotation and the achievement of a steady climbing condition.
This proposal harmonizes § 25.1323(c) with JAR-25.1323(c) at JAR Chg. 14. The FAA expects to achieve harmonization at Chg. 15, effective October 2000, through separate rulemaking that is currently underway.
JAR paragraphs 25.1323(c)(2), (3), and (4) contain requirements for speeds greater than and less than the speed range for which accuracy requirements apply. Part 25 does not have these additional requirements.
At speeds up to 2/3 (VDF − VMO) and less than the stall warning speed, JAR paragraphs 25.1323(c)(2) and (3) require the indicated speed to change perceptibly and in the same sense as the calibrated airspeed. At speeds up to VDF, the indicated airspeed must not change in an incorrect sense. In other words, the indicated airspeed should not go down when the actual airspeed is going up.
JAR paragraph 25.1323(c)(4) states that between the initiation of rotation and the achievement of a steady climbing condition during takeoff, there must not be an airspeed indication that would cause the pilot undue difficulty. An example of such an indication would be a significant pause or change in the rate of change in airspeed. Such effects could result from changes in the airflow pattern around the airplane due to the diminishing effect of the ground on the airflow pattern as the airplane climbs away.
The JAR standard is more stringent than part 25. An airspeed indicating system that complies with JAR 25.1323(c) ensures compliance with § 25.1323(c), but a system that complies with § 25.1323(c) may not comply with JAR 25.1323(c). Therefore, a system designed to comply with § 25.1323(c) may need to be modified to comply with JAR 25.1323(c).
In general, where the standards are the same, the FAA and JAA accept the same means of compliance. For the additional requirements contained in JAR-25, the JAA has published advisory material providing an acceptable means of compliance. For showing compliance with JAR 25.1323(c)(2), the rate of change of IAS with CAS should be not less than 0.75 from 1.3 VS to the stall warning speed. For showing compliance with JAR 25.1323(c)(3), the rate of change of IAS with CAS should be not less than 0.5 from VMO+2/3 (VDF−VMO). The JAA does not have specific advisory material associated with JAR 25.1323(c)(4).
The FAA proposes to revise § 25.1323 to add the additional airspeed system indication requirements of JAR 25.1323(c)(2), (3), and (4).
In addition, a new requirement is proposed concerning airspeed lag. With the advent of electronic instruments in the cockpit, the pneumatic signals from the pitot and static sources are processed and digitized in the Air Data Computer (ADC) and then filtered and transported to the cockpit display. Data processing and filtering cause a time lag in displaying the airspeed on the cockpit display. This can be an important consideration in the airspeed indicating system calibration during ground acceleration. As stated in § 25.1323(b), the calibration for an accelerated takeoff ground run must determine the “system error,” which is the relation between indicated and calibrated airspeeds. The system error is the sum of the pneumatic lag in the pressure lines, airspeed lag due to time lags in processing the data, and static source, position error.
The FAA considers adding these requirements to part 25 necessary to harmonize the actual wording of part 25 with the JAR on the issue of stall warning speeds, and to clarify the intent of the part 25 regulation. This addition would align the U.S. regulations with their European counterparts, and the wording of both airworthiness standards would be parallel in this respect. Furthermore, the addition of the airspeed lag requirement would codify what is current FAA policy. The JAA intends to add the airspeed lag requirement to JAR-25.
Adoption of this proposal is intended to benefit the public interest by standardizing the requirements, concepts, and procedures contained in the U.S. and European airworthiness standards without reducing, but potentially enhancing, the current level of safety.
The proposed standard continues to address the underlying safety issue in the same manner as the current standard. The additional JAR standards have been added for the purpose of harmonization.
The proposed standard increases the level of safety relative to 14 CFR part 25 Start Printed Page 26951by incorporating the additional JAR requirements. The additional requirement regarding airspeed lag codifies current FAA policy.
Since industry practice is to comply with both the FAR and the JAR, the proposed amendment would neither add any new or different objective to the current regulations, nor change the way that any current certification practice is applied. Instead, the intent of the new paragraphs is to clarify and codify the way that the FAA and JAA have traditionally applied the related rules.
Various options regarding the split between rule and advisory material were discussed to achieve the safety objective while ensuring flexibility in the means of compliance.
The FAA considered incorporating the JAR acceptable means of compliance material for the proposed speed requirements in the rule; however, it was decided that this would be too prescriptive and that it would preclude the use of other means of compliance that could also be found acceptable.
Another consideration was to include quantitative limits on the allowable level of airspeed bias and takeoff/accelerate-stop distance errors in the proposed airspeed lag requirement. ARAC concluded, and the FAA agrees, that the “one size fits all” approach does not work well here. A speed bias that varies may be significant for one airplane and not for another. A similar argument applies to the takeoff and accelerate-stop distance errors. Also, other mitigating factors may be more difficult to consider if prescriptive, quantitative values are included in the standard.
Finally, the ARAC working group considered retaining the airspeed lag policy as policy only and not including it as a regulatory standard. The working group determined that this means of compliance did not have a specific regulatory standard against which it was applied. The FAA agrees with the working group's determination that a regulatory standard is necessary to assure that future certifications continue to consider airspeed lag issues.
Adopting this proposal would eliminate an identified Significant Regulatory Difference (SRD) between the wording of part 25 and JAR-25, without affecting currently accepted industry design practices. The FAA expects more consistent interpretations of the rules and improved relations between regulatory authorities by eliminating this SRD.
To address the additional JAR requirements proposed for § 25.1323, the FAA plans to issue a revision to Advisory Circular (AC) 25-7A, “Flight Test Guide for Certification of Transport Category Airplanes.” The proposed revision would add the means of compliance currently accepted by the JAA as an acceptable means of showing compliance with the proposed revision to § 25.1323 discussed in this NPRM. AC 25-7A already contains adequate advisory material concerning the airspeed lag issue. Public comments concerning the proposed revision are invited by separate notice in this issue of the Federal Register.
In conducting these analyses, the FAA has determined that this proposal has benefits, but no costs, and that it is not “a significant regulatory action” as defined in the Executive Order 12866 nor “significant” as defined in DOT's Regulatory Policies and Procedures. Further, this proposed rule would not have a significant economic impact on a substantial number of small entities, would reduce barriers to international trade, and would not impose an Unfunded Mandate on state, local, or tribal governments, or on the private sector.
Because there are no apparent costs associated with this proposed rule, it does not warrant the preparation of a full economic evaluation for placement in the docket. The basis of this statement and for the above determinations is summarized in the following paragraphs. The FAA requests comments with supporting documentation in regard to the conclusions contained in this section.
Currently, airplane manufacturers must satisfy both part 25 and the European JAR-25 standards to certificate transport category airplanes in both the United States and Europe. Meeting two sets of certification requirements raises the cost of developing a new transport category airplane, often with no increase in safety. In the interest of fostering international trade, lowering the cost of airplane development, and making the certification process more efficient, the FAA, JAA, and airplane manufacturers have been working to create, to the maximum possible extent, a single set of certification requirements accepted in both the United States and Europe. As explained in detail previously, these efforts are referred to as “harmonization.”
This proposal rule would revise the airspeed indicating requirements of § 25.1323 to add airspeed indication requirements for speeds greater than and less than the speed range for which airspeed indication accuracy requirements currently apply, would require that airspeed indications not cause the pilot undue difficulty between the initiation of rotation and the achievement of a steady climbing condition during takeoff, and would also codify current FAA policy concerning airspeed lag. The FAA has concluded that, for the reasons previously discussed in the preamble, the adoption of these JAR requirements into 14 CFR part 25 is the most efficient way to harmonize these sections and, in so doing, the existing level of safety will be preserved.
The FAA estimates that there are no costs associated with this proposal. A review of current manufacturers of transport category airplanes certificated under part 25 has revealed that all such future airplanes are expected to be certificated under both 14 CFR part 25 and JAR-25. Since future certificated transport category airplanes are Start Printed Page 26952expected to meet the existing JAR requirement and this proposed rule simply adopts the same JAR requirement, manufacturers would incur no additional cost resulting from this proposal.
In fact, manufacturers are expected to receive cost-savings by a reduction in the FAA/JAA certification requirements for new airplanes. The FAA, however, has not attempted to quantify the cost savings that may accrue due to this specific proposal, beyond noting that, while they may be minimal, they contribute to a large potential harmonization savings.
The agency concludes that, since there is consensus among potentially affected airplane manufacturers that savings would result, further analysis is not required.
First, the net effect of the proposed rule is minimum regulatory cost relief. The proposed rule would require that new transport category airplane manufacturers meet just the “more stringent” European certification requirement, rather than both the United States and European standards. Airplane manufacturers already meet or expect to meet this standard as well as the existing 14 CFR part 25 requirement.
Second, all U.S. transport-airplane category manufacturers exceed the Small Business Administration small-entity criteria of 1,500 employees for airplane manufacturers. The current U.S. part 25 airplane manufacturers include: Boeing, Cessna Aircraft, Gulfstream Aerospace, Learjet (owned by Bombardier), Lockheed Martin, McDonnell Douglas (a wholly-owned subsidiary of The Boeing Company), Raytheon Aircraft, and Sabreliner Corporation.
The Trade Agreement Act of 1979 prohibits Federal agencies from engaging in any standards or related activities that create unnecessary obstacles to the foreign commerce of the United States. Legitimate domestic objectives, such as safety, are not considered unnecessary obstacles. The statute also requires consideration of international standards and, where appropriate, that they be the basis for U.S. standards. In addition, consistent with the Administration's belief in the general superiority and desirability of free trade, it is the policy of the Administration to remove or diminish, to the extent feasible, barriers to international trade, including both barriers affecting the export of American goods and services to foreign countries, and barriers affecting the import of foreign goods and services into the United States.
The energy impact of the proposed rule has been assessed in accordance with the Energy Policy and Conservation Act (EPCA) and Public Law 94-163, as amended (43 U.S.C. 6362), and FAA Order 1053.1. It has been determined that it is not a major Start Printed Page 26953regulatory action under the provisions of the EPCA.
2. Amend § 25.1323 by redesignating paragraphs (d) through (f) as paragraphs (h) through (j) and revising them, and adding new paragraphs (d) through (g) to read as follows:
(d) From 1.3 VS to the speed at which stall warning begins, the IAS must change perceptibly with CAS and in the same sense, and at speeds below stall warning speed the IAS must not change in an incorrect sense.
(e) From VMO to VMO+2/3 (VDF − VMO), the IAS must change perceptibly with CAS and in the same sense, and at higher speeds up to VDF the IAS must not change in an incorrect sense.
(f) There must be no indication of airspeed that would cause undue difficulty to the pilot during the takeoff between the initiation of rotation and the achievement of a steady climbing condition.
(g) The effects of airspeed indicating system lag may not introduce significant takeoff indicated airspeed bias, or significant errors in takeoff or accelerate-stop distances.
(h) Each system must be arranged, so far as practicable, to prevent malfunction or serious error due to the entry of moisture, dirt, or other substances.
(i) Each system must have a heated pitot tube or an equivalent means of preventing malfunction due to icing.
(j) Where duplicate airspeed indicators are required, their respective pitot tubes must be far enough apart to avoid damage to both tubes in a collision with a bird.
[FR Doc. 01-12103 Filed 5-14-01; 8:45 am]