5.251 备降距离 Distance To Alternate (DTA)
5.251 Distance To Alternate (DTA)
Definition/Description: The “Distance To Alternate” field defines either the direct (geodesic) distance from the Destination Airport or Fix to the Alternate Airport or the along track distance of an alternate Company Route.
Source/Content: When the Alternate Type field carries the character “A,” the Distance to Alternate field carries the straight line (geodesic) distance in nautical miles between the Destination Airport or Fix and the Alternate Airport as listed in Alternate Identifier fields. When the Alternate Type field carries the character “C,” the Distance to Alternate field carries the cumulative along track distance for the Alternate Company Route as listed in the Alternate Identifier fields.
Used On: Alternate Records
Length: 3 characters max.
Character Type: Numeric
5.251 备降距离
定义或描述：定义自目的地机场的直线(最短)距离，或者定位点至备降机场的直线距离，或者备份公司航路的沿航迹距离。
数据源或供选编码：当备降类型填写“A”时，至备降机场的距离采用直线距离，以NM表示与目的地机场或定位点和备降机场代码字段列出的备降机场之间的最短距离。当“备降类型”中填写“C”时，距离填写备降识别字段列出的备份公司航路的沿航迹累计距离。
应用范围：备降距离
字节数：最多3位
字符类型：数字
5.252 备降类型 Alternate Type (ALT TYPE)
5.252 Alternate Type (ALT TYPE)
Definition/Description: The “Alternate Type” field is an information processing indicator. The Alternate Destination can be defined as an airport or an airport and route to an airport. This field defines that an alternate airport or, an company route is defined in the Alternate Identifier fields.
Source/Content: The field will contain either the character “A” when an Airport is provided or the character “C” when a Company Route is provided.
Used On: Alternate Records
Length: 1 character
Character Type: Alpha
5.252 备降类型
定义或描述：是资料处理指示码。备降目的地机场可以定义为一个机场或一个机场和航线至一个机场。定义在备降识别字段中定义的一个备降机场或一条公司航路
数据源或供选编码：当是一个机场时填写“A”；当涉及公司航路时，填写“C”。
应用范围：备降记录
字节数：1位
字符类型：字母
5.253 主/备用备降场四码 Primary and Additional Alternate Identifier
5.253 Primary and Additional Alternate Identifier (ALT IDENT)
Definition/Description: The Primary Alternate Identifier and the Additional Alternate Identifiers (two through five) uniquely identify either an Alternate Airport or an Alternate Company Route. The determination of whether the content is an Airport Identifier or a Company Route Identifier is accomplished through the Alternate Type field.
Source/Content: The content of this field is determined by the customer.
Used On: Alternate Records
Length: 10 characters max
Character Type: Alpha/numeric
5.253 主/备用备降场四码
定义或描述：主要备降机场识别符和补充备降识别符(保存在2-5位)唯一说明是备降机场还是备份公司航路。确定其内容是一个机场四码还是一条公司航路的识别，要与备降类型字段一起考虑。
数据源或供选编码：本项内容由用户决定。
应用范围：备降记录
字节数：最多10位
字符类型：字母/数字
5.254 固定半径过渡标识符 Fixed Radius Transition Indicator
5.254 Fixed Radius Transition Indicator (FIXED RAD IND)
Definition/Description: Indicates that a specific turn radius from the inbound course to the outbound course is required by the airspace controlling agency.
Source/Content: When a fix radius turn is required a 3 digit numeric value will be entered in this field representing the radius of the turn to 1 decimal place (tenths, decimal point suppressed) in nautical miles. A blank entry in this field indicates that no fixed radius transition is required.
Used On: Enroute Airway Records
Length: 3 characters
Character Type: Numeric
Examples: 225=22.5nm, 150=15.0 nm
5.254 固定半径过渡标识符
定义或描述：表示空域管理部门要求从入航航径到出航航径需要一个规定的转弯半径。
数据源或供选编码：作一个规定转弯需要3位数字的半径值填入，半径值以海里为单位NM，省略小数点，表示到小数后一位。如本项为空，则表示不需要规定的半径过渡。
应用范围：航路航线记录
字节数：3位
字符类型：数字
举例：225＝22.5nm、 150＝15.0nm
5.255 SBAS服务商代号 SBAS Service Provider Identifier
5.255 SBAS Service Provider Identifier (SBAS ID)
Definition/Description: The “SBAS Service Provider Identifier” field is used to associate the approach procedure to a particular satellite based approach system service provider.
Source/Content: A number from 00 to 15, the exact definition of which is currently under development by ICAO SBAS SARPS working groups.
Used On: Path Point Records
Length: 2 characters
Character Type: Numeric
5.255 SBAS服务商代号
定义或描述：用于将进近程序与一个特定的星基进近系统服务商相联系。
数据源或供选编码：数字00-15， 当前定义是:
| 供选项 | 内容 |
|---|---|
| 0 | WAAS |
| 1 | EGNOS |
| 2 | MSAS |
| 3 | GAGAN |
| 4 | SDCM |
| 5-13 | (空) |
| 14 | Not intended for SBAS, used as the CRC default value for GBAS |
| 15 | Any Service provider may be used |
应用范围：SBAS航径点记录
字节数：2位
字符类型：数字
5.256 基准航径数据选择 Reference Path Data Selector
5.256 Reference Path Data Selector (REF PDS)
Definition/Description: The “Reference Path Data Selector” field enables the automatic tuning of a procedure by Ground Based Augmentation Systems (GBAS) avionics.
Source/Content: A number from 00 to 48, the exact definition of which is currently under development by ICAO GBAS SARPS working groups.
Used On: Path Point Records
Length: 2 characters
Character Type: Numeric
5.256 基准航径数据选择
定义或描述：此字段使陆基增强系统(GBAS)能自动转换到一个程序，此数据不用于SBAS运行。
数据源或供选编码：通过接收波道来选择数字00-48，在SBAS记录中设为0。
应用范围： SBAS和GBAS航径点记录
字节数：2位
字符类型：数字
5.257 基准航径代码 Reference Path Identifier
5.257 Reference Path Identifier (REF ID)
Definition/Description: The “Reference Path Identifier” field is used to provide an identifier that can be used to confirm selection of the correct approach procedure.
Source/Content: The content will be derived from official government sources and analogous to the Morse code identifier on existing ILS approach Procedures.
(Editor comment: See Section 5.243, GLS Station Identifier.)
Used On: Path Point Records
Length: 4 characters
Character Type: Alpha/numeric
Examples: GDCA, SJK2
5.257 基准航径代码
定义或描述：用3或4位字母/数字的识别符以确定唯一基准航径，它和处在仪表进近板（ Plates ）上的通道号下方的进近程序标识同义，而且在指定的机场中是唯一的。
数据源或供选编码：使用大写字母或数字。来源于官方，类似以莫尔斯代码来识别目前的ILS进近程序。使用当前习惯的名称作为它的关键字，如W表示WAAS、E表示EGNOS，但并不作强制规定，也可能使用其他字符。其后跟随跑道号和一个后缀字母。就空间程序中的点而言，最后进近航段的航道数据按照10度取整，然后填充到跑道号中。
应用范围： SBAS和GBAS航径点记录
字节数：4位
字符类型：字母/数字
举例： W12A, E27A, W34A
5.258 进近性能编号 Approach Performance Designator
5.258 Approach Performance Designator (APD)
Definition/Description: The “Approach Performance Designator” field is used to indicate the type or category of approach.
Source/Content: A number between 0 and 7. The content will be derived from official government source documents. The ICAO GBAS SARPS working groups will provide the complete assignment.
Used On: Path Point Records
Length: 1 character
Character Type: Alpha
Example: 1 (Category I Approach)
5.258 进近性能编号
定义或描述：此字段用于说明进近程序类别或等级，此数据不用于SBAS运行。
数据源或供选编码：0-7的一个数字，具体如下表。在SBAS航径点记录中为0。
| 内容 | 描述 |
|---|---|
| 0 | GAST A or GAST B |
| 1 | GAST C |
| 2 | GAST C or GAST D |
| 3-7 | Spare |
注释:依据 RTCA DO-253，GAST表示GBAS 进近服务类型，GBAS进近服务类型依据机载和地基设备的性能、功能方面的可量化指标确定。
应用范围： SBAS和GBAS航径点记录
字节数：1位
字符类型：数字
举例： 1(1类进近)
5.259 偏置长度 Length Offset (OFFSET)
5.259 Length Offset (OFFSET)
Definition/Description: The “Length Offset” field is the distance from the stop end of the runway (SER) to the FPAP. This distance defines the location where lateral sensitivity changes to the missed approach sensitivity. If the FPAP is located at the designated center of the opposite runway end, the distance is zero.
Source/Content: A value, expressed in meters, derived from official government sources (Explanation and details will appear in appropriate FAA and ICAO documents). The actual resolution is 8 meters.
Used On: Path Point Records
Length: 4 characters
Character Type: Numeric
Examples: 0000, 0432
5.259 偏置长度
定义或描述：为跑道停止端至FPAP的距离。此距离定义从水平感应转到复飞感应的位置。如果FPAP位于反向跑道端的规定中心，则该距离为0。
数据源或供选编码：来源于官方，以米为单位的数值表示(具体规定在FAA和ICAO文件中解释)，实际分辨率为8米。
应用范围：航径点记录
字节数：4位
字符类型：数字
举例：0000、0432
5.260 终端程序计划航段距离 Terminal Procedure Flight Planning Leg Distance
5.260 Terminal Procedure Flight Planning Leg Distance (LEG DIST)
Definition/Description: The Terminal Procedure Flight Planning Leg distance is the along track distance required to complete any given leg. It is used to determine a cumulative track distance for a given terminal procedure for flight planning purposes, from the beginning of the take-off or arrival point to the termination point of the procedure.
Source/Content: The values will be determined during route definition of the procedure records. The content is controlled through requirements of the Path and Termination and coding rules in force with the data supplier. The values are expressed in nautical miles and tenths of nautical miles, with the decimal point suppressed.
Used On: Airport and Heliport SID, STAR and Approach Procedure Flight Planning Continuation Records
Length: 4 characters
Character Type: Numeric
Examples: 0176, 0822, 0208 0016, 0100
5.260 终端程序计划航段距离
定义或描述：是规定航段的沿航迹距离。此距离应用于飞行计划，确定一个规定终端程序的累计航迹距离，该距离从起飞开始或到达点至程序终止点的距离。
数据源或供选编码：该数值在程序记录定义航线的过程中确定。其内容由数据商采用的终端航径编码要求来管理。该值以nm为单位，表示到1/10nm，省略小数点。
应用范围：机场的SID STR 进近程序、飞行计划续记录。
字节数：4位
字符类型：数字
例： 0176、0822、0208、0016、0100
本文采用 署名-非商业性使用-相同方式共享 4.0 国际 许可协议，转载请注明出处。
