0 U.S. Department of Transportation Federal Aviation Administration Advisory Circular Subject: Landing Performance Data for Time-of-Arrival Landing Performance Assessments Date: 12/22/15 AC No: 25-32 Initiated By: ANM-111 This advisory circular (AC) provides guidance and standardized methods that data providers, such as type certificate (TC) holders, supplemental type certificate (STC) holders, applicants , and airplane operators, can use when developing landing performance data for time-of-arrival landing performance assessments for transport category airplanes. This AC also promotes the use of consistent terminology for runway surface conditions used among data providers and FAA personnel.
If you have suggestions for improving this AC, you may use the Advisory Circular Feedback p:;;:;et~ Jeffrey E. Duven Manager, Transport Airplane Directorate Aircraft Certification Service
Contents Paragraph Page ii
1 Purpose1
2 Applicability1
3 Related Documents1
3.1 Regulations1
3.2 Advisory Circulars2
3.3 Other Documents2
4 Background2
5 Time-of-Arrival Landing Performance Assessments3
6 Definitions4
6.1 Dry Runway4
6.2 Wet Runway5
6.3 Contaminated Runway5
6.4 Loose Contaminants6
6.5 Pilot-Reported Braking Action6
6.6 Runway Condition Code7
6.7 Runway Surface Condition7
6.8 Solid Contaminants7
6.9 Slippery When Wet7
6.10 Specific Gravity7
6.11 Wheel Braking Coefficient7
7 Time-of-Arrival Performance Data8
8 Determination of Landing Distance for Time-of-Arrival Landing Performance Assessments.10
8.1 Landing Distance10
8.2 Air Distance11
8.3 Transition Distance12
8.4 Final Stopping Configuration Distance (Full Braking Distance)15
9 Accounting for Drag of Loose Contaminants15
10 Credit for Reverse Thrust16
11 Guidance for Existing Type Designs18
12 Documentation19
Contents (continued) Paragraph Page iii
12.1 Data Location19
12.2 Data Label19
12.3 Other Information19
Figures
Figure 1. Landing Distance Segments10
Tables
Table 1. Runway Surface Condition—Descriptions and Contaminant Category8
Table 2. Runway Surface Condition—Pilot-Reported Braking Action—
Wheel Braking Coefficient Correlation Matrix14
Table 3. Loose Contaminant Specific Gravity16
1 1 PURPOSE.
This AC provides guidance and standardized methods that data providers, such as TC holders, STC holders, applicants, and airplane operators, can use when developing landing performance data for time-of-arrival landing performance assessments for transport category airplanes. This AC also promotes the use of consistent terminology for runway surface conditions used among data providers and FAA personnel.
2 APPLICABILITY.
2.1 The guidance provided in this document is directed towards airplane manufacturers, modifiers, foreign regulatory authorities, FAA transport airplane type certification engineers, flight test pilots, flight test engineers, and their FAA designees.
2.2 The guidance in this AC is neither mandatory nor regulatory in nature and does not constitute a requirement. This AC is written in response to an Aviation Rulemaking Committee (ARC) recommendation to provide guidance to manufacturers for a standardized approach for computing time-of-arrival landing performance data.
2.3 This material does not change or create any additional regulatory requirements, nor does it authorize changes in, or permit deviations from, regulatory requirements.
2.4 The guidance provided in this AC can be used both for new airplane designs and for previously certificated airplane designs. See section 11 of this AC for additional information on applying the guidance in this AC to previously certificated airplane designs.
3 RELATED DOCUMENTS.
3.1 Regulations.
The following Title 14, Code of Federal Regulations are referenced in this AC. These regulations are available at the U.S. Government Printing Office website.
• Section 25.101, General (Performance).
• Section 25.125, Landing.
• Section 25.1587, Performance information.
• Section 91.1037, Large transport category airplanes: Turbine engine powered;
Limitations; Destination and alternate airports.
• Section 121.195, Airplanes: Turbine engine powered: Landing limitations:
Destination airports.
• Section 135.385, Large transport category airplanes: Turbine engine powered:
Landing limitations: Destination airports.
3.2 Advisory Circulars.
The following ACs are referenced in this AC. These ACs are available at the FAA website. If any AC is revised after publication of this AC, you should refer to the latest revision.
• AC 25-7C, Flight Test Guide for Certification of Transport Category Airplanes, dated October 16, 2012.
• AC 25.939-1, Evaluating Turbine Engine Operating Characteristics, dated March 19, 1986.
• AC 150/5200-28E, Notices to Airmen (NOTAMs) for Airport Operators, dated October 8, 2015.
3.3 Other Documents.
• FAA Order JO 7930.2Q (or later revision), Notice to Airmen (NOTAM), dated December 18, 2015.
• European Aviation Safety Agency (EASA) Acceptable Means of Compliance (AMC) 25.1591, The Derivation and Methodology of Performance Information for use when Taking-off and Landing with Contaminated Runway Surface Conditions.
• Safety Alert for Operators (SAFO) 06012, Landing Performance Assessments at Time of Arrival (Turbojets), dated August 31, 2006.
4 BACKGROUND.
4.1 Following the overrun of a Southwest Airlines Boeing Model 737-700 series airplane at Chicago Midway International Airport on December 8, 2005, the FAA conducted an internal review to evaluate the adequacy of regulations and guidance in areas that came under scrutiny during the course of the accident investigation. Among other findings, the FAA identified areas to improve in the regulations, guidance, and industry practices for conducting landing performance assessments at the time of arrival, including concerns about the landing performance data provided by TC holders. These concerns include questions about whether these data are representative of in-service operational practices, whether these data are presented in a standardized format, how the landing distances are computed, and how the data are presented.
4.2 To address some of these concerns, the FAA issued SAFO 06012 on August 31, 2006.
SAFO 06012 urgently recommended that operators of turbojet airplanes develop procedures for flightcrews to assess landing performance based on conditions existing at the time of arrival at the destination airport. On August 6, 2007, the FAA tasked the Takeoff and Landing Performance Assessment (TALPA) ARC to provide a forum for the U.S. aviation community to discuss incorporating the recommended actions identified in SAFO 06012 into regulatory requirements.
4.3 The TALPA ARC completed its actions and delivered its recommendations to the FAA on July 7, 2009. Although the Committee recommended adopting regulations requiring
3 TC holders to produce landing performance data for time-of-arrival landing performance assessments, the FAA does not currently plan to initiate rulemaking on this issue.
4.4 After the Committee delivered its recommendations to the FAA, the FAA worked with two airlines and 29 airports to validate the Runway Condition Codes of the contaminants on the Runway Condition Assessment Matrix (RCAM)1 and the feasibility of obtaining an accurate rating of the runway surface condition from airport operations personnel using the TALPA ARC recommended methods. This validation testing lasted two winter seasons (2009-2010 and 2010-2011). After the first season of validation testing, the validation team made modifications to the original RCAM based on the data collected from the airports and correlated pilot braking action reports. These modifications were re-validated the second winter season. The Committee then used this data as the basis for its final recommended RCAM.
4.5 This AC provides guidance and standardized methods that data providers can use, at their option, to develop landing performance data for time-of-arrival (or en route) landing performance assessments. Data created following the recommendations of this AC would address the majority of the Committee recommendations for data providers.
The created data would also be consistent with the terminology used for airport reporting of runway conditions.
5 TIME-OF-ARRIVAL LANDING PERFORMANCE ASSESSMENTS.
5.1 Sections 91.1037, 121.195, and 135.385 prescribe landing performance requirements that must be met at the time of takeoff. However, compliance with these requirements does not account for the time-of-arrival conditions of the runway that will be used for landing, when calculating whether the airplane can safely land within the distance available on that runway. The distance needed to safely complete the landing at the time of arrival may be different if the runway, runway surface condition, meteorological conditions, approach guidance, airplane configuration, airplane weight, approach speed, or use of airplane ground deceleration devices differs from that used to show compliance with § 91.1037, § 121.195, or § 135.385.
5.2 To enhance safety, procedures developed by airplane operators to assess landing performance at the time of arrival should include an adequate safety margin and should consider runway surface conditions/braking action, winds, temperatures, slope, pressure altitude, icing condition, final approach speed, airplane weight and configuration, and deceleration devices used.
5.3 Appropriate landing performance data would assist operators in performing these time-of-arrival landing performance assessments. Because of differences in the
1 The RCAM is a matrix relating runway condition codes and runway surface conditions.
4 variables to be taken into account and how the data are to be used, the landing performance data for time-of-arrival landing performance assessments may be different than the landing performance data developed in accordance with § 25.125 and provided in the airplane flight manual in accordance with § 25.1587(b).
5.4 Part 25 landing distances are determined in a way that represents the maximum performance capability of the airplane, which may not be representative of normal operations. For use in time-of-arrival landing performance assessments, where the conditions at the time of arrival are known and taken into account, it would be beneficial if the landing performance data were representative of actual operations. The data for time-of-arrival landing performance assessments should represent expected landing performance by a trained flightcrew of average skill following normal flight procedures and training.
5.5 Like the landing distances defined in § 25.125, the landing distances for use with time-of-arrival landing performance assessments, if developed, should consist of the horizontal distance from the point at which the main gear of the airplane is 50 feet above the landing surface to the position of the nose gear when the airplane is brought to a stop. See figure 1 on page 10.
5.6 An important portion of the TALPA ARC’s recommendations concerns the use of a common set of terms for describing runway surface conditions. The FAA agrees with the ARC that it would be beneficial for all parties involved in determining, transmitting, and using runway surface condition information to use the same terms and the same definitions for those terms. The FAA is issuing guidance information, including this AC, promoting use of common runway surface condition nomenclature for—
• Runway surface condition descriptions used in field condition reports originated by airports,
• Runway surface condition reports relayed by air traffic controllers,
• Development of airplane performance data for different runway surface conditions by data providers, and
• Use of field condition reports and airplane performance data by pilots and airplane operators to make their time-of-arrival landing performance assessments.
6 DEFINITIONS.
6.1 Dry Runway.
A runway is dry when it is neither wet nor contaminated. For purposes of condition reporting and airplane performance, a runway can be considered dry when no more than 25 percent of the runway surface area (within the reported length and the width being used) is covered by visible moisture or dampness, frost, slush, snow (any type), or ice.
6.2 Wet Runway.
A runway is wet when it is neither dry nor contaminated. For purposes of condition reporting and airplane performance, a runway can be considered wet when more than 25 percent of the runway surface area (within the reported length and the width being used) is covered by any visible dampness or water that is ⅛ inch (3 mm) or less.
Note: A damp runway that meets this definition is considered wet, regardless of whether or not the surface appears reflective.
6.3 Contaminated Runway.
For purposes of condition reporting and airplane performance, a runway is considered contaminated when more than 25 percent of the runway surface area (within the reported length and the width being used) is covered by frost, ice, and any depth of snow, slush, or water. Definitions for each of these runway contaminants are provided in paragraphs 6.3.1 through 6.3.8 of this AC.
Note: The definition of water in the context of condition reporting and airplane performance is the definition in paragraph 6.3.6 of this AC, which is a depth of greater than ⅛ inch (3 mm). This terminology is consistent with the definitions used in NOTAMs as published in AC 150/5200-28E and Order JO 7930.2Q (or later revisions).
6.3.1 Dry Snow.
Snow that has insufficient free water to cause it to stick together. This generally occurs at temperatures well below 32 ºF (0 ºC). If when making a snowball, it falls apart, the snow is considered dry.
6.3.2 Wet Snow.
Snow that has grains coated with liquid water, which bonds the mass together, but that has no excess water in the pore space. A well-compacted, solid snowball can be made, but water will not squeeze out.
6.3.3 Slush.
Snow that has water content exceeding a freely drained condition such that it takes on fluid properties (for example, flowing and splashing). Water will drain from slush when a handful is picked up. This type of water-saturated snow will be displaced with a splatter by a heel and toe slap-down motion against the ground.
6.3.4 Compacted Snow.
Snow that has been compressed and consolidated into a solid form that resists further compression such that an airplane will remain on its surface without displacing any of it. If a chunk of compressed snow can be picked up by hand, it will hold together or can be broken into smaller chunks rather than falling away as individual snow particles.
6.3.5 Frost.
Frost consists of ice crystals formed from airborne moisture that condenses on a surface whose temperature is below freezing. Frost differs from ice in that the frost crystals grow independently and, therefore, have a more granular texture.
6.3.6 Water.
Water in a liquid state. For purposes of condition reporting and airplane performance, water is greater than ⅛ inch (3 mm) in depth.
6.3.7 Ice.
The solid form of frozen water.
6.3.8 Wet Ice.
Ice that is melting or ice with any depth of water on top.
6.4 Loose Contaminants.
Loose contaminants are those contaminants that an airplane’s tire will not remain on the surface of without breaking through. Water, slush, wet snow, and dry snow are loose contaminants. For loose contaminants, the depth of the contaminant can affect both the airplane’s acceleration and deceleration capability.
6.5 Pilot-Reported Braking Action.
Pilot-reported braking action is a subjective assessment of runway slipperiness. The pilot bases the assessment on observations of braking deceleration and directional controllability during landing rollout. Since the type of runway contaminant is not identified in a pilot braking action report, landing performance data based on pilot-reported braking action should not include any effects of contaminant drag.
Braking action can be categorized with the terms provided in paragraphs 6.5.1 through
6.5.6 of this AC.
6.5.1 Good.
Braking deceleration is normal for the wheel braking effort applied, and directional control is normal.
6.5.2 Good-to-Medium.2 Braking deceleration or directional control is between good and medium2 braking action.
6.5.3 Medium.2 Braking deceleration is noticeably reduced for the wheel braking effort applied, or directional control is noticeably reduced.
6.5.4 Medium-to-Poor.2 Braking deceleration or directional control is between medium2 and poor.
2 The braking action term “FAIR” is in the process of being changed to “MEDIUM” throughout the FAA. Until an official change is published, the term “FAIR” may be used.
6.5.5 Poor.
Braking deceleration is significantly reduced for the wheel braking effort applied, or directional control is significantly reduced.
6.5.6 Nil.
Braking deceleration is minimal to non-existent for the wheel braking effort applied, or directional control is uncertain.
6.6 Runway Condition Code.
The runway condition code is a number from 0 to 6 that is used to denote the category of slipperiness of a designated portion of a runway (that is, a specific one-third of the runway), with 0 being extremely slippery and 6 being a dry runway. Since runway condition code reflects only the runway slipperiness (that is, any effect of contaminant drag is not included), the runway condition code can be directly correlated with a pilot-reported braking action.
6.7 Runway Surface Condition.
The runway surface condition is a description of the contaminants (if any) on the surface of a runway. Takeoff and landing performance data based on runway surface condition may include the effects of the contaminant on braking friction and the effects of contaminant depth on drag as appropriate.
6.8 Solid Contaminants.
Solid contaminants are those contaminants that an airplane’s tire will remain on top of and not break through. Compacted snow and ice are solid contaminants. For solid contaminants, the depth of the contaminant does not affect the airplane’s acceleration and deceleration capability.
6.9 Slippery When Wet.
A wet runway where the surface friction characteristics would indicate diminished braking action as compared to a normal wet runway.
6.10 Specific Gravity.
The specific gravity of a contaminant is the density of the contaminant divided by the density of water.
6.11 Wheel Braking Coefficient.
Wheel braking coefficient is the ratio of the deceleration force from a braked wheel/tire relative to the normal force acting on the wheel/tire. The wheel braking coefficient is an all-inclusive term that incorporates effects related to the tire-to-ground interaction from braked wheels only, such as runway surface and airplane braking system (e.g., anti-skid efficiency, brake wear, tire condition, etc.). For the purposes of this AC, the wheel braking coefficient is based on a fully modulating anti-skid controlled braked wheel/tire. The definition of fully modulating anti-skid system is found in AC 25-7C.
8 7 TIME-OF-ARRIVAL PERFORMANCE DATA.
7.1 If developed using the guidance in this AC, landing performance data should be provided in terms of both runway surface condition descriptions and pilot-reported braking actions for the approved operational envelope for landing. The following runway surface condition descriptions and pilot-reported braking actions should be included:
7.1.1 Runway Surface Condition Description.
See table 1 of this AC.
Table 1. Runway Surface Condition—Descriptions and Contaminant Category Runway Surface Condition Description Contaminant Category Dry — Wet — Ice Solid contaminant Compacted snow Solid contaminant Dry snow Loose contaminant Wet snow Loose contaminant Slush Loose contaminant Water Loose contaminant
7.1.2 Pilot-Reported Braking Action.
See paragraph 6.5 of this AC for the definition of pilot-reported braking action. It can be categorized with the following terms, which are defined in paragraphs 6.5.1 through
6.5.6, respectively, of this AC:
• Good.
• Good-to-medium.3
• Medium.3
• Medium-to-poor.3
3 The braking action term “FAIR” is in the process of being changed to “MEDIUM” throughout the FAA. Until an official change is published, the term “FAIR” may be used.
• Poor.
Note: Landing performance data is not presented for Nil because this is not a performance category but rather a report from the flightcrew that flight operations should cease on this runway until the airport has taken an action to improve the braking action.
7.2 Landing distance data should cover all normal operations with all engines operating within the normal landing operating envelope. The effect of each of the parameters affecting landing distance should be provided, and should take into account the following:
7.2.1 Approved landing configurations, including Category III landing guidance where approved;
7.2.2 Approved deceleration devices (for example, wheel brakes, speedbrakes/spoilers, and thrust reversers);
7.2.3 Pressure altitudes within the approved landing operating envelope;
7.2.4 Weights up to the maximum takeoff weight;
7.2.5 Expected airspeeds at the runway threshold, including speeds up to the maximum recommended final approach speed considering possible speed additives for winds and icing conditions;
7.2.6 Temperatures within the approved landing operating envelope;
7.2.7 Winds within the approved landing operating envelope (1) not more than 50 percent of the nominal wind components along the landing path opposite to the direction of landing; and (2) not less than 150 percent of the nominal wind components along the landing path in the direction of landing;
7.2.8 Runway slopes within the approved landing operating envelope; and
7.2.9 Icing conditions, if required to provide the landing distances required under § 25.125 in icing conditions.
7.3 Data providers should provide appropriate information for minimum equipment list and configuration deviation list items that affect landing distance.
7.4 Data providers are also encouraged to include landing distances for non-normal configurations.