今天遇到个TAF中的积冰预报不会读，找了好久才找到最权威的出处。报文如下：
TAF UUDD 012255Z 020006 19006MPS 3000 BR OVC005 TEMPO 0200/0207 0700 FZDZ FZFG OVC003 640000 BECMG 0207/0209 6000 NSW BKN007
其中积冰项的高度和深度怎么都是0？
《中华人民共和国民用航空行业标准民用航空气象第6部分：电码》的航路预报ROFOR中有解释。4是积冰类型，000代表积冰底部<50米，最后一个0代表厚度直到云顶。
WMO的《WMO_306_vol I.1_en》中的航路预报也有相同解释。
至于为什么UUDD把航路预报的积冰内容报在TAF里，我就不知道了。也许是想强调一下FZ的严重程度吧。
对于738飞机的一个反推减载有一个简单的方法：FPPM中
Thrust Reverser Inoperative
When dispatching on a wet runway with both thrust
reversers operative, an operative anti-skid system, and
all brakes operating, regulations allow deceleration
credit for one thrust reverser in the engine failure case
and two thrust reversers in the all engine stop case.
When dispatching on a wet runway with one thrust
reverser inoperative, the runway/obstacle limited
weight and V1 must be reduced to account for the effect
on accelerate-stop performance. A simplified method,
which conservatively accounts for this, is to reduce the
normal wet runway/obstacle limited weight by 1000 kg
and the V1 associated with the reduced weight by 2
knots.
If the resulting V1 is less than minimum V1, takeoff is
permitted with V1 set equal to V1(MCG) provided the
accelerate-stop distance available corrected for wind
and slope exceeds approximately 1600 m.
Detailed analysis for the specific case from the Airplane
Flight Manual may yield a less restrictive penalty.
757/767的FPPM里没找到有这句话。可以用“Slippery Runway Takeoff – No Reverse Thrust”这张表格减载。