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45523 Rules and Regulations Federal Register Vol. 62, No. 167 Thursday, August 28, 1997 This section of the FEDERAL REGISTER passenger, pressurized, low-winged, the early 1960's, thrust reversers were contains regulatory documents having general ``T'' tailed, transport category airplane developed to reverse both the fan and applicability and legal effect, most of which with retractable tricycle type landing core exhaust flows, thus maintaining the are keyed to and codified in the Code of gear. The airplane is powered by two availability of auxiliary braking. With Federal Regulations, which is published under Allison Model AE3007A high bypass the advent of large high bypass ratio 50 titles pursuant to 44 U.S.C. 1510. ratio turbofan engines mounted on the turbofan engines in the late 1960s, many The Code of Federal Regulations is sold by aft fuselage, which are controlled by a thrust reverser systems reversed the fan the Superintendent of Documents. Prices of Full Authority Digital Engine Control exhaust flow only, which provided a new books are listed in the first FEDERAL (FADEC). The cockpit will include a substantial auxiliary braking effect due REGISTER issue of each week. complete set of Electronic Flight to the majority of the total inlet flow Instrumentation and Engine Indication going through the fan section. and Crew Alerting Systems (EFIS and Numerous test programs, by both DEPARTMENT OF TRANSPORTATION EICAS). research organizations and aerospace Embraer has proposed to certificate manufacturers, have substantiated the Federal Aviation Administration and market the EMB±145 with thrust increased stopping benefit provided by 14 CFR Part 25 reversers as optional equipment. Thrust thrust reversers as runway surface reversers have been shown to play a friction conditions deteriorate. [Docket No. NM±134; Special Conditions significant role in reducing accelerate- The vast majority of jet-powered No. 25±ANM±131] stop distances on wet and contaminated transport category airplanes in service Special Conditions: Empresa Brasileira runways and have contributed to the have been of the large, passenger de Aeronautica S.A., (EMBRAER) transport category airplane fleet's carrying variety. Research shows that Model EMB±145 Airplane; Thrust accelerate-stop safety record. with the exception of a very limited Reverser Systems The establishment of the transport number of airplane types, some of category airplane safety record, with which had considerably slower takeoff AGENCY: Federal Aviation regard to accelerate-stop and landing and landing speeds than their Administration (FAA), DOT. overruns, is tied to the availability of counterparts, all these large, passenger ACTION: Final special conditions. auxiliary braking means that are carrying, turbojet/turbofan-powered independent of wheel-brake, tire, and transports included thrust reverser SUMMARY: These special conditions are runway surface interaction. On early systems as part of their basic design for the Empresa Brasileira de transport category airplanes with (i.e., as standard equipment). The last Aeronautica S.A., (EMBRAER) Model propellers driven by reciprocating such aircraft certified without thrust EMB±145 airplane. This airplane will engines or turbine powerplants, reversers as part of the basic design was have a novel or unusual design feature auxiliary braking was provided by the British Aerospace 146 (BAe 146) in associated with thrust reversers as commanding the propellers to a reverse 1983. When the sheer numerical optional equipment. These special pitch position, causing a deceleration, majority of these large transports is conditions contain the additional safety rather than acceleration, of air through combined with their high-use operating standards which the Administrator the propeller disk. Due to the large environment, often requiring takeoffs considers necessary to establish a level diameter of the propellers, this was and landings to be made on slippery of safety equivalent to that established quite an effective braking means. runway surfaces, it is clear that thrust by the airworthiness standards of part Though these early transports did not reversers must have played a role in 25 of the Federal Aviation Regulations have the high operating speeds of establishing their excellent safety (FAR). today's jet fleet, they also did not benefit record. EFFECTIVE DATE: September 29, 1997. from the sophisticated wheel-brake It should also be noted that as the FOR FURTHER INFORMATION CONTACT: antiskid systems available today. As number of small transport category Colin Fender, FAA, Flight Test and runway friction conditions degrade to airplanes in service has increased, Systems Branch of the Transport those associated with a surface covered notably corporate jets and regional Standards Staff, ANM±111, Transport by ice, even today's antiskid systems airliners, there has been an increasing Airplane Directorate, Aircraft will provide little in the way of stopping tendency for these airplanes to be Certification Service, 1601 Lind Avenue force. As runway friction conditions equipped with some type of thrust SW, Renton, Washington 98055±4056; degrade, the braking contribution of reversing system. Nearly all the regional telephone 425±227±2191. reverse pitch systems increases airliners are turbopropeller-powered SUPPLEMENTARY INFORMATION: considerably. with reverse pitch capability, and an As the first generation turbojet- increasing number of corporate jets Background powered transport category airplanes include thrust reversers as standard Embraer first made application for a went into service in the latter half of the equipment. U.S. Type Certificate for the Model 1950s, thrust reverser systems were The accelerate-stop and landing EMB±145 on August 30, 1989, to the developed to provide this same type of distances presented in the FAA FAA Atlanta Aircraft Certification auxiliary braking as reverse pitch approved Airplane Flight Manual Office through the Brazilian Centro propellers by reversing the engine (AFM) are determined from TeÂcnico Aeroespacial (CTA). On June 2, exhaust flow. As powerplant technology measurements of the various influential 1992, Embraer filed for an extension of evolved and low bypass ratio turbofan parameters taken during certification that application. The EMB±145 is a 50 engines entered commercial service in flight tests. These flight tests are 45524 Federal Register / Vol. 62, No. 167 / Thursday, August 28, 1997 / Rules and Regulations accomplished by FAA test pilots (or reliability and controllability criteria are adequacy pursuant to section 611 of manufacturers' Designated Engineering met). Public Law 92±574, the ``Noise Control Representative (DER) test pilots) under The accelerate-stop certification basis Act of 1972.'' controlled conditions on dry runways. for the EMB±145 is § 25.109, as If the Administrator finds that the In the operational environment, even on amended by Amendment 25±42, applicable airworthiness regulations dry runways, the ability of an airplane effective March 1, 1978. Thrust (i.e., part 25 as amended) do not contain to match the AFM accelerate-stop reversing systems are not required by adequate or appropriate safety standards performance is based on many factors, the FAR and, when installed, no for the Model EMB±145 because of a including the correct and timely performance credit is granted for their novel or unusual design feature, special execution of procedures by the pilot and availability in the dry runway conditions are prescribed under the maximum stopping performance being accelerate-stop distances required by provisions of § 21.16. available from the wheel braking § 25.109, as amended by Amendment Special conditions, as appropriate, are system. As runway surface conditions 25±42, effective March 1, 1978. issued in accordance with § 11.49 after degrade to wet, contaminated, or icy, However, the vast majority of transport public notice, as required by §§ 11.28 the accompanying reduction in category airplanes in service at the time and 11.29(b), and become part of the available friction will result in an the regulatory changes of Amendment type certification basis in accordance increase in stopping distances, causing 25±42 were promulgated were equipped with § 21.17(a)(2). the wet runway accelerate-stop with thrust reversers. Consequently, the Special conditions are initially distances to exceed the dry runway certification of transport category applicable to the model for which they accelerate-stop distances published in airplanes intended to be operated in are issued. Should the type certificate the AFM. Obviously, if the takeoff is Part 121-type commercial service for that model be amended later to runway length-limited as determined without thrust reversers was not include any other model that from the dry runway AFM accelerate- envisaged at the time Amendment 25± incorporates the same novel or unusual stop distances, and the runway surface 42 was promulgated. design feature, these special conditions is anything but dry, the probability for In consideration of the intended would also apply to the other model an overrun accident is increased operation of the EMB±145, the FAA under the provisions of § 21.101(a)(1). considers the non-inclusion of thrust significantly. (This increased risk factor Novel or Unusual Design Features is acknowledged for the landing reversers into the basic airplane to be an The Model EMB±145 will have an scenario in part 121, the operating rules unusual design feature that is not