为啥没有高温修正?

昨天,有位同事提醒我,他发现万州机场11号跑道的RNP APCH程序有个高温限制。如图:

所以,我见过高温限制在60摄氏度的。万州机场28摄氏度的高温限制,真是第一次见到。这个温度在今天(春季)就会被突破,今天的最高温度预报为30度,那就更别说大夏天了。

我本来的想法是,既然有低温修正,那应该也可以做高温修正咯。然而,似乎不是这样。我找了一下波音的FCTM,原文如下:

Boeing airplanes have uncompensated Baro-VNAV systems and are prohibited from using LNAV/VNAV minima on approach charts when operating outside of published temperature restriction limits. However, if cold temperature altitude corrections are applied as described in the Cold Temperature Operations Supplementary Procedures chapter of the FCOM, descent to the corrected LNAV (MDA) minima is allowed. There is no procedure for hot temperature corrections.

波音说,没有高温修正这回事。。。。

题外话,关于FCTM的这段文字,公司似乎有个翻译的歧义。原文的意思应该是:当温度超过航图上的温度限制时,不能使用Baro-Vnav的LNAV/VNAV;但是在温度超过航图上的温度限制时,可以做完修正后,使用LNAV。

但是有人会把这句话理解为,只要做了温度修正,不管当前温度是否超过航图限制,都不能使用LNAV/VNAV程序。

FAA发布过一个《Cold Temperature Restricted Airports》。文中提供了一个快速修正的表格,以及修正的例子:

For RNAV (GPS) approaches flown to the LNAV/VNAV line of minima using baro-VNAV vertical guidance, determine if there are published uncompensated baro-VNAV temperature limits. If the reported airport temperature is above or below the published limits, do not use the LNAV/VNAV line of minima unless the RNAV system is capable of temperature compensation and the system is active. Use an alternative line of minima (e.g., LNAV). CTRA correction must still be made on this approach if applicable.

根据低温修正的情况看,高温修正是忽略的。但是就和低温修正一样,如果当前温度超过高温限制,LNAV/VNAV自然是不能用了。但是LNAV仍然能用。

PS:空客的情况我还没找到,如果谁有相关的依据,请告诉我。

 

为啥没有高温修正?》上有2条评论

发表评论