9.6 If the data provider chooses to develop data using the process described in this AC, the effects of crosswinds on directional controllability should be assessed and particular attention paid to the possibility of reverse thrust affecting airflow over the rudder and vertical tail surface. Thrust reverser use may even reduce directional controllability in combinations of crosswinds and low friction conditions. Recommendations or guidelines associated with crosswind takeoffs, including maximum recommended crosswinds, should be provided to operators for the runway surface conditions for which takeoff performance data are provided. A suitable simulation may be used to develop these guidelines for operation on contaminated runways.
9.7 If the data provider, in using the process described in this AC, applies credit for asymmetric reverse thrust, then controllability should be accounted for in that configuration. The reverse thrust procedures may specify a speed at which the reverse thrust is reduced to idle in order to maintain directional controllability.
9.8 The failure of the thrust reverser to function should be on the order of 10-4 or less per takeoff. This specific reliability requirement applies to both single and combinations of failures and takes into account interlock features intended to prevent inadvertent in-flight deployment.
9.9 The effective stopping force provided by reverse thrust in each, or at the option of the data provider, the most critical takeoff configuration, should be established by flight test. (One method of determining the reverse thrust stopping force would be to compare unbraked runs with and without the use of thrust reversers.) Regardless of the method used to calculate the effective stopping force provided by reverse thrust, flight tests should be conducted using all of the stopping means on which the accelerate-stop distances are based in order to calculate those distances and ensure that no adverse combination effects are overlooked. These tests may be conducted on a dry runway.
9.10 For turbopropeller powered airplanes, the guidance in paragraphs 9.1 through 9.9 above remain generally applicable. Additionally, the propeller of the inoperative engine should be in the position it would normally assume when an engine fails and the power lever is closed. Reverse thrust may be selected on the remaining engine(s). Unless this selection is achieved by a single action to retard the power lever(s) from the takeoff setting without encountering a stop or lockout, it should be regarded as an additional pilot action for the purposes of assessing delay times.
10 GUIDANCE FOR EXISTING TYPE DESIGNS.
The guidance in this section applies to data already produced to support airplane models already in service.
10.1 The following information is intended to facilitate the use of existing data to the maximum extent possible, in order to limit the burden associated with developing and producing new data packages.
10.2 Contaminated runway takeoff performance data approved by either the Joint Aviation
11 Authorities or EASA in compliance with either their contaminated runway type certification or operating requirements are acceptable when using the optional process identified in this AC, with the caveats provided in paragraphs 10.2.1 and 10.2.2 below.
The FAA recognizes that such data may not be consistent with the guidance provided in this AC in terms of braking coefficients associated with each runway surface condition description and the magnitude of the contaminant drag for loose contaminants.
10.2.1 Data providers should develop data that account for all of the runway surface condition descriptions identified in table 2 of this AC (unless operating limitations prohibit operations on runway surface conditions for which data are not provided).
10.2.2 Definitions of the runway surface conditions should be consistent with the definitions provided in this AC. In particular, a damp runway is to be considered wet for airplane performance purposes.
10.3 Reverse thrust credit may be included without specifically accounting for reliability or controllability. However, reverse thrust credit should not be used if service history for a particular airplane model indicates unresolved reliability or controllability issues.
11 DOCUMENTATION.
11.1 Data Location.
The data provider may furnish the contaminated runway takeoff performance data in the airplane flight manual, flightcrew operating manual, quick reference handbook, electronic flight bag, and/or other appropriate locations.
11.2 Data Label.
If the data provided is not certified or approved by a certification agency, it should be labeled as “Advisory Data Only” or similar wording.
11.3 Other Information.
If a data provider develops contaminated runway takeoff performance data described in this AC, the following information should also be provided:
11.3.1 Instructions for use of the data.
11.3.2 Definitions of the different runway surface conditions.
11.3.3 Recommendations prohibiting taking off on runways with contaminants and depths not covered in the performance data.
11.3.4 Any other recommendations associated with use of the contaminated runway takeoff performance data.
11.3.5 Statements that the data are based on a uniform depth (for loose contaminants) and uniform coverage of a layer of contaminant with uniform properties throughout.
Advisory Circular Feedback If you find an error in this AC, have recommendations for improving it, or have suggestions for new items/subjects to be added, you may let us know by (1) emailing this form to 9-AWA-AVS- AIR500-Coord@faa.gov or (2) faxing it to the attention of the Aircraft Certification Service Directives Management Officer at (202) 267-3983.
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