Part61/Part141航校

Flight schools that operate under Part 141 of the FARs are strictly regulated by FAA, their flight and ground school courses must be FAA-approved. Students who learn better in a structured climate will choose a Part 141 school.

141部航校,严格受FAA管理,飞行课程和地面课程必须是批准的。

Instructors at a Part 61 school should operate from a syllabus, just as a Part 141 school, but they are not required to do so. Ground school is not required at a Part 61 school. If your life and work schedule do not fit into a relatively strict training regime,  Part 61 is for you.

61部航校,不要求严格按照培训大纲培训。可以没有地面课程。如果你的生活和工作时间无法保证连续的训练的话,可以选择61部航校。

The airplanes and instructors at both types of school must meet the same standards.

61部航校和141部航校的飞机、教员的安全水平都是一样的标准。

看来,我应该选择61部航校。

关于备降标准计算时是否考虑风向的争论

我不记得我是什么时候从“不考虑风向”转变为“考虑风向”的。我曾经坚定的认为,计算备降标准时可以不考虑风向,因为备降标准的增加值可以“覆盖掉”跑道的选择。

但是近几年我觉得我错了。随着运行规范的更新,我慢慢地成为了“考虑风向”的坚定支持者。我会将风速超标的跑道先删除,再计算备降标准。因为运行规范C0013中明确写了,考虑跑道适用性时,需要考虑风的情况,其中还包括不超过侧风。

但是业内还有另一部分人,认为121部中没有要求,所以不必考虑。或者是认为,法规只要求“考虑”,没说怎么“考虑”。

而在各公司争论此事时,局方却没有站出来,澄清法规的想法。我觉得局方的不作为,比争论本身更难以忍受。希望在121R5中能明确一下。

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另外,附上英文原版。(2016年5月17日最新更新了ETOPS运行备降场计算时遇到GPS/GNSS标准时的计算方法)

N 8900.364 OpSpec/MSpec/LOA C055, Alternate Airport IFR Weather Minimums》

3)When determining the suitability of a runway, wind (including gust) must be forecast to be within operating limits (including reduced visibility limits) and should be within the manufacturer’s maximum demonstrated crosswind.

738快点飞塞班去

今天塞班遇到个通告:
PGSN APT 201508176B4V01 A0252/15
Q)KZAK/QFFCG/IV/NBO /A /000/999/N1507.2E14543.8
A)PGSN B)201508210428 C)201508280700
E)AD AIRCRAFT RESCUE AND FIRE FIGHTING NOW INDEX C
消防等级变为C级。
根据FAR 139.315 Aircraft rescue and firefighting: Index determination.
(1) Index A includes aircraft less than 90 feet in length.
(2) Index B includes aircraft at least 90 feet but less than 126 feet in length.
(3) Index C includes aircraft at least 126 feet but less than 159 feet in length.
(4) Index D includes aircraft at least 159 feet but less than 200 feet in length.
(5) Index E includes aircraft at least 200 feet in length.
C级的最大长度为159英尺。
A330的长度为193英尺,如果不考虑消防等级降一级的话,A330就不能飞了。

前段时间还在说道,要用738飞ETOPS去塞班,有些人(包括我)都觉得没必要。
现在看出必要性了吧。。。。。。。。。。。。。。。。。。。。。。。。。。。
。。。。。。。。。。。。。其实通告时间也不长。。。。。。。。。。。。。。

起飞后ETOPS航路备降场的天气要求

曾经121升级成R4的时候牢牢记住了:“ETOPS航路备降场的天气标准和普通计划备降场的相同”。一直到现在被人问到两者有什么区别的时候,我回答:“一样呀”。

哎,业务不精啊~~~。两者还是有那么一点点区别的。

第 121.724 条 初始签派或飞行放行,二次签派或重新签派或飞行放行
(a)只有在下列条件下,才能允许飞机继续飞行并越过延程运行进入点:
(1)除本条(b)规定外,对于本规则第 121.722 条要求的每一个延程运行备降机场,在可能使用这些备降机场之时(从最早到最晚的可能着陆时间),其预报天气条件均等于或高于合格证持有人运行规范中规定的机场最低天气标准;
(b)如果某一机场无法达到本条第(a)(1)项的要求,可对签派或飞行放行单进行更改,增加一个飞机能以批准的最大改航时间飞抵的,天气条件等于或者高于最低运行标准的延程运行备降机场

FAA原文:

(c) No person may allow a flight to continue beyond the ETOPS Entry Point unless—
(1) Except as provided in paragraph (d) of this section, the weather conditions at each ETOPS Alternate Airport required by §121.624 are forecast to be at or above the operating minima for that airport in the certificate holder’s operations specifications when it might be used (from the earliest to the latest possible landing time); and
(2) All ETOPS Alternate Airports within the authorized ETOPS maximum diversion time are reviewed and the flight crew advised of any changes in conditions that have occurred since dispatch.

根据121.724条,要求在飞跃进入点前(不是起飞前,起飞前用实况预报的结合)整个时间窗口内预报的天气都不能低于落地标准。普通的备降场没有这个要求。如果不能满足a项要求,可以增加一个最大改航时间内的备降机场。增加一个航路备降场的事我还没遇到过,公司手册中对于起飞后至进入点前预报中出现的TEMPO、PROB和PROB TEMPO的参考依据也没说的很清楚,怎么样增加一个航路备降场的方法说的也不清楚。反正以后上班时要格外注意航路上机场的TEMPO情况了。

 

RDH和TCH

在翻阅温州的国内航图时,我发现03号ILS的图上写的是RDH,但是03号RNAV(GNSS)的图上写的是TCH。

相同的数值却用不同的名字表示,这是为什么呢?

我先去找了AIP的简字简语,发现只有“RDH”的定义:“Reference datum height (for ILS)仪表着陆系统基准数据点高”

ICAO对于两者的定义为:
RDH =  Reference datum height (RDH). The height of the extended glide path or a nominal vertical path at the runway threshold.
TCH = Threshold crossing height

在微博上问了一些人,CAVOK_祎告诉了我一个非官方的答案:

“TCH and RDH are one in the same, but in the real world the radiated signal is influenced by the surrounding environment resulting in the TCH and RDH not necessarily being equal.”

我在FAA上又找到了个文件:“ASSESSMENT OF THE EFFECTIVENESS OF THE RDH/ARDH EVALUATION METHODOLOGY FOR THE ILS GLIDE SLOPE

我只是粗略地看了一些图片,大概明白是什么道理了。在以前,当一个下滑道建立好之后,可以用它的安装角和设备离跑道入口的距离来换算出下滑道信号在跑道入口上方的高,称之为TCH,计算方法见下图:

后来,因为受环境的影响,实际的下滑道信号和理想的下滑道信号之间有区别,所以计算的TCH和实际的TCH之间也有差别:

再后来,干脆用飞机去飞一遍,测量实际的下滑道路径,并在路径上选择两个点,画一条直线,直线的延长线在跑道入口上相交的高就叫做RDH:

文中的其他内容,我就没有信心看下去了。 但是文中28页:“COMPARISON – ICAO VERSUS FAA TCH/RDH/ARDH METHODS”可以看一下,它说到了ICAO对TCH/RDH的做法。我想中国应该也遵循这个做法:

ICAO Doc 8071 “Manual on Testing of Radio Navigation Aids: Vol I – Testing of Ground-Based Radio Navigation Aids” [12]. Below is the only RDH reference found in all ILS related ICAO documents surveyed:

Section 4.3.81 Reference Datum Height (RDH)

For commissioning and categorization flight tests, it may be necessary to determine the glide path RDH. This is done using a high-quality approach recording, from which the angle and structure measurements are made. Position-corrected DDM values for a selected portion of the approach (typically from Pt A to Pt B for Cat I and the last mile of the approach for Cat II and III facilities) are used in a linear regression to extend a best-fit line downward to a point above the threshold. The height of this line above the threshold is used as the RDH. If the tolerances are not met, an engineering analysis is necessary to determine whether the facility should be used for the regression analysis, or another type of analytical technique should be used.”

可见ICAO对于RDH的说法和美国人的差不多。

—————————————————————————————————————————-

总结一下:1)RDH肯定比单纯计算的TCH好,应为RDH考虑了无线电信号受干扰,实际下滑道不等于计算的下滑道的情况。2)没有电子下滑道的程序,应该算不出RDH。所以说温州的RNAV(GNSS)用的是TCH表示。(我猜的,我也不清楚类精密进近是怎么规定的,目前的文件看是没有RDH。)

如果真如航图上所写的,中国老多机场都用RDH,那么说明我们民航发展是蛮先进的。因为ICAO也说到“Allow each member country to determine their need for performing RDH assessments.”。RDH非强制,看来我国是有财力和能力来计算RDH的。我猜其中也有那架KingAir校飞飞机的功劳?

但是希望中国的AIP中快点加上TCH的解释,否则以后考试时,被问道TCH是什么,我就可以理直气壮的说不知道。

至于为什么jeppesen只有TCH而没有RDH,我就难以理解了。

又一个会产生歧义的MEL,767的单空调21-51-1

昨天值班时遇到个767单空调的MEL。虽然自己心里清楚放行标准是什么,就怕机组来问,解释起来会很麻烦。幸好下班了。交给下个班去处理。哈哈

中文是这样写的:

要求在60分钟内有一个“合适的备降机场”。

英文版是这样写的:

要求:flight remains within 60 minutes of landing at a suitable airport.

我觉得中文版中的“合适的备降机场”很容易使人误解为按备降标准放行。误解为航路上60分钟内都有一个机场,而且放行时机场的天气标准满足备降标准。

但是从CCAR121.712的合适机场的定义来考虑:

合适机场:是指达到第121.197条规定的着陆限制要求且局方批准合格证持有人使用的机场,它可能是下列两种机场之一:
(1)合适机场是经审定适合大型飞机公共航空运输承运人所用飞机运行的,或符合其运行所需等效安全要求的机场,但不包括只能为飞机提供救援和消防服务的机场;
(2)对民用开放的可用的军用机场。

且不说这条翻译的瑕疵。121.712条所指的“合适机场”肯定是不需要按备降标准来放行的。何况现在根本就不是ETOPS。

121.712对应的FAA是121.7 Definitions.     把“合适机场” 称为Adequate Airport,不是Suitable airport。(真不知道翻译的人脑子是不是搭错了)

The following definitions apply to those sections of part 121 that apply to ETOPS:
Adequate Airport means an airport that an airplane operator may list with approval from the FAA because that airport meets the landing limitations of §121.197 and is either—
(1) An airport that meets the requirements of part 139, subpart D of this chapter, excluding those that apply to aircraft rescue and firefighting service, or
(2) A military airport that is active and operational.

所以,综上所述,本次航班不是ETOPS,不考虑航路机场的天气标准,而且就算用ETOPS中“合适机场”的定义,也是不需要计算备降标准来放行的。

我觉得解决办法是把MEL中的“合适的备降机场”改为“合适机场”,对应121.712的定义。或者更直接的办法是改为“不执行ETOPS飞行”,避免和ETOPS的那些定义纠缠在一起。

签派员在放行时是否应该坚持“最低”标准?(是否可取高标准?)

最近遇到的两件事让我产生一个疑惑:签派员在和机长沟通放行时,是否应该(或者必须)坚持“最低”标准。

例一:早晨放行某个航班,目的地机场辐射雾,实况报告RVR400米,预报转好。最低落地标准RVR550米。由于是航程在1小时以内的航班,所以我建议机长在天气达到最低标准后再起飞。接着在计划起飞时刻前,机场特选报RVR550,达到最低标准,因此我通知机长放行。但是机长要求达到RVR800才放行,理由是目的地机场的气象是出了名的不准,常常是RVR报告够标准,但是机长无法建立目视参考,只能备降。机长所说情况我也有同感,因为我曾经也被此机场气象台“吃药”。最后我让步,等待RVR够800米再起飞。

例二:从某机场起飞前,平衡报告机长通知其限制最大起飞重量,必须限制业载。我检查了起飞性能分析,发现应该有足够的性能可以装下全部业载,所以我和机长沟通并核对起飞性能表。原来机长称不愿用FLAP5+改进爬升,因为V1速度大,又是特殊机场,风向不定,起飞时可能有顺风。对此我同意机长的说法,无奈业载较多,我对机组说用空调关起飞吧,虽然效果不明显,至少可以略微多装些业载。但是机长依然不同意。我们几个签派员讨论后,决定更改飞行计划,选择一个较近的备降场,并通知机长抽油。在我们的坚持下机长同意用FLAP1起飞,就不用抽油了。我和机长核对了一下性能表,就正常放行了。

以上两个例子中的放行条件都是高于公司/法规规定的“最低”标准的。我的疑问是,签派和机长是否有权利临时提高放行的“最低”标准?

从法规上看:

第121.633条  仪表飞行规则的签派或者放行
除本规则第 121.635 条规定外,按照仪表飞行规则签派或者放行飞机飞行前,应当确认相应的天气实况报告、预报或者两者的组合,表明在签派或者放行单中所列的每个机场的天气条件,在飞机预计到达时处于或者高于经批准的最低标准,否则,不得签派或者放行飞机按照仪表飞行规则飞行。

第121.677 条  国内、国际定期载客运行的签派责任
合格证持有人应当根据授权的飞行签派员所提供的信息,为两个规定地点之间的每次飞行编制签派单。机长和授权的飞行签派员应当在签派单上签字。机长和授权的飞行签派员均认为该次飞行能安全进行时,他们才能签字。对于某一次飞行,飞行签派员可以委托他人签署放行单,但是不得委托他人行使其签派权。

FAA原话:

121.663   Responsibility for dispatch release: Domestic and flag operations.
Each certificate holder conducting domestic or flag operations shall prepare a dispatch release for each flight between specified points, based on information furnished by an authorized aircraft dispatcher. The pilot in command and an authorized aircraft dispatcher shall sign the release only if they both believe that the flight can be made with safety. The aircraft dispatcher may delegate authority to sign a release for a particular flight, but he may not delegate his authority to dispatch.

我在法规上没有找到明确给予签派或者机长临时提高“最低”标准的内容(如果有谁找到了请告诉我)。但是法规121.677条赋予机长和签派不签字的权利,双方应该彼此尊重对方的权利。公司也要尊重他们的权利,只要他们有一个合理的理由。

和机组沟通放行的时候,有些机长会说:“只要你们签派放,我就飞”之类的话。我会对他强调一下,签派和机长是共同放行。放行像一场谈判,最终的结果是保证安全。没有谁服从谁或者谁命令谁的做法。

综上所述, 我认为,签派员不必坚持“最低”标准。机长和签派员可以临时提高“最低”标准。只要双方有合理的理由,并达成一致。

最低油量 & Minimum Fuel & Emergency Fuel

上海区域的一次雷雨,让我感觉我对最低油量的概念需要好好认识一下。

以下所有内容都是法规要求,和实际操作无关。

先从CCAR 121.555说起:

第121.555 条 最低油量的宣布
(a)当出现最低燃油量状况时,机长应当遵守下列规定:
(1)向空中交通管制员宣布“最低油量”;
(2)向空中交通管制员报告剩余的可用燃油还能飞多少分钟;
(3)继续按照空中交通管制员同意的航路飞行
(4)通知飞行签派员,已宣布了最低油量;
(5)如果按照目视飞行规则或者在无雷达地区实施运行,报告现在位置和预计到达目的地的时间。
(b)最低油量是指飞行过程中应当报告空中交通管制员采取应急措施的一个特定燃油油量最低值。该油量是在考虑到规定的燃油油量指示系统误差后,最多可以供飞机在飞抵着陆机场后,能以等待空速在高于机场标高 450米(1500英尺)的高度上飞行 30分钟。

121.555中明确说明了最低油量的定义和计算方法,以及机组需要做的事。最重要的是对“最低油量”定性为“应当报告空中交通管制员采取应急措施”。所以我觉得在国内发生的“最低油量”是一种“Emergency”。

当最低油量发生时,签派应该拿出应急手册:

12、最低油量宣布
(a)当最低燃油条件存在时:
飞行签派员在接到消息—我公司某一航班已宣布最低油量,应当
(1)首先,报告公司领导。
(2)通过无线电频率或空中交通管制部门与空中飞机和空中交通管制部门保持不间断联系,密切掌握情况,直到班机安全着陆。
(3)向空中交通管制部门申请改变航线和优先着陆。同时,向机组提供就近机场资料、飞行情报和气象资料;联系有关机场当局,告知有关情况,通知其做好应急救援的组织和准备工作。
(4)如机长决定选择场外迫降时,按照搜寻和援救的程序进行工作。

所以,综上所述:在中国,当机组宣布最低油量时,机组向ATC报告剩余油量时间,继续按ATC同意的航路飞行(没说申请直飞)。签派应该向ATC申请改变航路(直飞?)和优先着陆。ATC采取应急措施。

———————————————————————————–

接着我查了一下FAA关于Minimum fuel的说明,见下文:

INFO: <Comparison of Minimum Fuel, Emergency Fuel and Reserve Fuel>

FAA的121部中没有对应的555条,只有AIM中说到Minimum fuel。以上这个INFO是我在FAA网站里找到的,明确把Minimum fuel和Emergency Fuel区分清楚。文中对Minimum fuel的定义是:

“Indicates that an aircraft’s fuel supply has reached a state where, upon reaching the destination, it can accept little or no delay. This is not an emergency situation but merely indicates an emergency situation is possible should any undue delay occur.”

“If an aircraft declares a state of “minimum fuel,” inform any facility to whom control jurisdiction is transferred of the minimum fuel problem and be alert for any occurrence which might delay the aircraft en route.”

Note: Use of the term “minimum fuel” indicates recognition by a pilot that his/her fuel supply has reached a state where, upon reaching destination, he/she cannot accept any undue delay. This is not an emergency situation but merely an advisory that indicates an emergency situation is possible should any undue delay occur. A minimum fuel advisory does not imply a need for traffic priority. Common sense and good judgment will determine the extent of assistance to be given in minimum fuel situations. If, at any time, the remaining usable fuel supply suggests the need for traffic priority to ensure a safe landing, the pilot should declare an emergency and report fuel remaining in minutes.

对Emergency Fuel的定义:

The point at which, in the judgment of the pilot-in-command, it is necessary  to proceed directly to the airport of intended landing due to low fuel. Declaration  of a fuel emergency is an explicit statement that priority handling by ATC is both required and expected.

FAA中遇到minimum fuel时,机组还将按照原航路飞行,只是不能接受更多延误,只有在需要申请优先权才能安全落地的情况下,才宣布“Emergency”,并报告剩余燃油时间。

———————————————————————————–

那么,综合FAA和CAAC的解释来说:

从事件严重等级上看,FAA的”Minimum Fuel” 和CAAC的“最低油量”能否画上等号呢?我觉得显然不能。CAAC的“最低油量”更像是FAA的”Emergency Fuel”。

从机上剩油的角度上看,FAA的”Minimum Fuel” 和CAAC的“最低油量”能否画上等号呢?由于INFO中有说明”Minimum Fuel”的具体数值是:

There is no regulatory definition as to when, specifically, a pilot must declare “minimum fuel” or a fuel emergency. Air carriers typically develop such guidance for their pilots and include it in their General Operations Manuals; such guidance generally falls along the following lines:
• Declare “minimum fuel” when, in your best judgment, any additional delay will cause you to burn into your reserve fuel.
• Declare a fuel emergency at the point at which, in your judgment, it is necessary for you to proceed directly to the airport at which you intend to land. Declaration of a fuel emergency is an explicit statement that priority handling by ATC is necessary and expected.

可见FAA没有规定何时“When”机组必须报告 “minimum fuel or a fuel emergency”(和中国不同)。因此美国的“minimum fuel”是一个公司政策。这个公司政策通常是:“机组判断,继续Delay将会需要用到reserve fuel时,宣布最低油量;机组判断,机上剩油必须申请直飞和优先权才能安全落地时,宣布fuel emergency”。

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JAR 中对于”Minimum Fuel”有类似的定义:JAR 1.375 。。。。略。。。。(可能中东用的是JAR?)

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ICAO  Doc 4444 – Air Traffic Management Chapter 1. Definitions:

Minimum fuel:  The term used to describe a situation in which an aircraft’s fuel supply has reached a state where little or no delay can be accepted.

note.- This is not an emergency situation but merely indicates that an emergency situation is possible, should any undue delay occur.

ICAO的Minimum fuel和FAA的定义是一样的,甚至更简单一些。ICAO中说Minimum fuel的内容很少,而且我资料不全,很难找。

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现在说说问题。

问1)我按照公司政策做了一份合法的飞行计划:从RKPC飞ZSPD备降ZSHC

BOF ZSPD    3923 00.58  0339NM  0358AIR  PAYLOAD:   0.0  W/C  M027
ALTN ZSHC   2049 00.27  0127NM                      MXSH 03/AKARA
FINAL RES   1666 00.30
CONT 10 PC   335 00.06         LIMIT / PLANNED           / ACTUAL
TANKERING      0           ZFW 126.1 /  90.9             / ......
BALLAST        0           LDW 136.1 /  96.8     TO FUEL / ......
REQUIRED    7973 02.01     TOW 186.9 / 100.7     NEW TOW / ......
EXTRA       1800 00.32                           DIFF    / ......
TAKEOFF     9773 02.33
TAXI         400           ADJUST PER 5000 KGS IN TOW      000122 KGS
TOTAL      10173 02.33     FUEL ADJ FOR PERF DEGREDATION P02.1PC

由于业载是0吨,公司备份油正常值是1800KG,所以飞机很轻,所以“FINAL RES”部分的油量很小(1666KG X 2.2046 = 3678LB)。公司手册中767的最低油量是一个固定值=5000LB=2268KG。
因为RKPC-ZSPD是一条很短的航线。所以百分之10的备份油也很少。如果有一个机组完全按照我这份计划加油,并以9773KG的油量起飞了,在航路上用掉了“CONT 10 PC 335KG”,在浦东机场等待32分钟用完了1800KG的公司备份油,但是最后不得不去杭州备降。他会发现根本不可能再去杭州了(和计划矛盾),因为此时FMC中显示的预计落地剩油应该是1666KG,已经少于公司手册中的最低油量。他要么宣布最低油量(直飞去杭州),要么在浦东机场继续等待。
所以说,这份合法的计划中有不合理的地方。解决办法可以是:把“FINAL RES”的值固定为手册最低油量6000LB(这个办法有点傻逼);或者增加公司备份油,特别是针对短时间的国际航班。(这个方法可行,但是复杂)。
假如从反向计算,在浦东机场还没明确是否能落地前,最低的机上剩油应该是:备降杭州2049KG + 手册中最低油量5000LB = 4317KG,一旦低于这个油量,就不能去杭州了,除非宣布最低油量。

问2)如果一个美国航班在中国宣布了Minimum fuel,那么中国的管制应该怎么做?给他优先权吗?

问3)如果一个中国的航班在美国宣布了最低油量,那么美国的管制应该怎么做?给他优先权吗?如果签派收到机组报告的最低油量信息,按照公司应急手册执行,能要求美国的管制给予直飞或者优先权吗?人家会同意吗?

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雷雨那天,我很幸运,所有的飞机都在外面飞行,没有因为雷雨备降或等待的航班。我写这篇博文不是想分清楚事件的责任人,而是提供一个对法律规章讨论的起点。

如果有朋友觉得我说的太过脱离实际(纸上谈兵、事后诸葛之类),我非常渴望听到实际飞行情况和经验。

Braking Action Reports And Runway Friction Reports

4-3-8. Braking Action Reports and Advisories

a. When available, ATC furnishes pilots the quality of braking action received from pilots or airport management. The quality of braking action is described by the terms “good,” “fair,” “poor,” and “nil,” or a combination of these terms. When pilots report the quality of braking action by using the terms noted above, they should use descriptive terms that are easily understood, such as, “braking action poor the first/last half of the runway,” together with the particular type of aircraft.

b. For NOTAM purposes, braking action reports are classified according to the most critical term (“fair,” “poor,” or “nil”) used and issued as a NOTAM(D).

c. When tower controllers have received runway braking action reports which include the terms poor or nil, or whenever weather conditions are conducive to deteriorating or rapidly changing runway braking conditions, the tower will include on the ATIS broadcast the statement, “BRAKING ACTION ADVISORIES ARE IN EFFECT.”

d. During the time that braking action advisories are in effect, ATC will issue the latest braking action report for the runway in use to each arriving and departing aircraft. Pilots should be prepared for deteriorating braking conditions and should request current runway condition information if not volunteered by controllers. Pilots should also be prepared to provide a descriptive runway condition report to controllers after landing.

刹车效应报告由“好中差”和“无”构成。由飞行员报告,主观感觉差异较大。当刹车效应报告不佳,或有影响刹车效应的情况出现时,管制员要在ATIS中报 “BRAKING ACTION ADVISORIES ARE IN EFFECT.”

4-3-9. Runway Friction Reports and Advisories

a. Friction is defined as the ratio of the tangential force needed to maintain uniform relative motion between two contacting surfaces (aircraft tires to the pavement surface) to the perpendicular force holding them in contact (distributed aircraft weight to the aircraft tire area). Simply stated, friction quantifies slipperiness of pavement surfaces.

b. The greek letter MU (pronounced “myew”), is used to designate a friction value representing runway surface conditions.

c. MU (friction) values range from 0 to 100 where zero is the lowest friction value and 100 is the maximum friction value obtainable. For frozen contaminants on runway surfaces, a MU value of 40 or less is the level when the aircraft braking performance starts to deteriorate and directional control begins to be less responsive. The lower the MU value, the less effective braking performance becomes and the more difficult directional control becomes.

d. At airports with friction measuring devices, airport management should conduct friction measurements on runways covered with compacted snow and/or ice.

1. Numerical readings may be obtained by using any FAA approved friction measuring device. As these devices do not provide equal numerical readings on contaminated surfaces, it is necessary to designate the type of friction measuring device used.

2. When the MU value for any one-third zone of an active runway is 40 or less, a report should be given to ATC by airport management for dissemination to pilots. The report will identify the runway, the time of measurement, the type of friction measuring device used, MU values for each zone, and the contaminant conditions, e.g., wet snow, dry snow, slush, deicing chemicals, etc. Measurements for each one-third zone will be given in the direction of takeoff and landing on the runway. A report should also be given when MU values rise above 40 in all zones of a runway previously reporting a MU below 40.

3. Airport management should initiate a NOTAM(D) when the friction measuring device is out of service.

e. When MU reports are provided by airport management, the ATC facility providing approach control or local airport advisory will provide the report to any pilot upon request.

f. Pilots should use MU information with other knowledge including aircraft performance characteristics, type, and weight, previous experience, wind conditions, and aircraft tire type (i.e., bias ply vs. radial constructed) to determine runway suitability.

g. No correlation has been established between MU values and the descriptive terms “good,” “fair,” “poor,” and “nil” used in braking action reports.

跑道摩擦系数MU,从0至100,0为最差。当冰冻的污染物覆盖跑道,MU低于40,表明飞机的刹车效果开始恶化,方向控制开始失去响应。当三分之一的跑道开始出现MU小于40的情况时,MU的数值就应该由机场当局报告给ATC以便通知到飞行员。当MU值回升至40以上时,同样也要报告。MU值和刹车效应之间没有关联。(据性能人员称,两者之间还是有联系的)

在SNOTAM的H项有个类似的内容,MU值也是从0.40以下开始计算的。虽然表格没有明确说MU值和刹车效应之间一一对应的关系,但至少暗示了其中的关系。就凑活着用吧。

Area Navigation (RNAV)

AIM 5-1-8 d. Area Navigation (RNAV)
1. Random RNAV routes can only be approved in a radar environment. Factors that will be considered by ATC in approving random RNAV routes include the capability to provide radar monitoring and compatibility with traffic volume and flow. ATC will radar monitor each flight, however, navigation on the random RNAV route is the responsibility of the pilot.
2. Pilots of aircraft equipped with approved area navigation equipment may file for RNAV routes throughout the National Airspace System and may be filed for in accordance with the following procedures………
(e) Define the random route by waypoints. File route description waypoints by using degree- distance fixes based on navigational aids which are appropriate for the altitude stratum.
3. Pilots of aircraft equipped with latitude/longitude coordinate navigation capability, independent of VOR/TACAN references, may file for random RNAV routes at and above FL 390 within the conterminous U.S. using the following procedures.

1.Random RNAV航路只在雷达监控的环境下执行。

2.对机载设备的要求。(e)航路上的点用degree-distance fixes based on navigational aids方法表示。(详见AC 20-138B)

3.在FL390以上飞行的Random RNAV必须要装备latitude/longitude导航能力,并不依赖VOR/TACAN