B737NG Speed Limitations

[5milesbaby]

With the skies getting busier and the need for ATC to put more a/c in trail earlier and earlier, it has made me wonder what the Airline briefings consist of for airframe speed limited a/c.

As a controller the need to know that an a/c has a 270kt descent restriction is crutial for the 'plan of action' through the sector. Therefore I believe that on first contact with the Centre at least, or more the sector that descent will commence in, any limitations should be declared within the initial call on frequency. What do your SOP's say for this?? Is it even considered?

Hopefully if you fly such aircraft and at the moment you don't let us know you now will consider doing so, its happenned to me about 5 times, and the last almost led to an overload and subsequent 1261 being filed. It DOES matter.

[ManaAdaSystem]

The 270 kts limitation is only applicable after deicing with type 2 or 4 fluids. Otherwise, .82/340 is the max speed.
Some guys don't fly above 300 because of cockpit noise.
For a while we were limited to 300 when using speed brakes.
Cost index 35 (used by some) will give apx 280 kts during descent.

If I am limited to 270 (or any other speed) I will inform you. If my descent speed is 280 (but not limited to), I will not.
What do you consider to be "normal" speeds during descent?

[Bomber Harris]

5miles,
good question. And you phrased it perfectly....exactly as a pilot would see it. "What do your SOP's say for this??"

Well unfortunately the answer is probably nothing. My company SOP's don't cover it. The reason being that this is a result of an AD (airworthiness Directive) issued by Boing which just covers the technical aspects of how to operate the aircraft under the conditions of the AD. Boeing will not tell you how to liase with ATC, that is an airline 'thing'....non-technical. As it is a temporary measure (until aircraft are modified with new elevator trim tabs) my guess is that most airlines will tell their crews to 'operate as per the AD' rather than writing amplified procedures which will be binned as the fleet upgrade programs roll on, which is what my company basically did.

However, the crews are starting to realise that it causes you a problem and are now pre-empting this, but obviousy not eveyone. Indeed I remeber listening to a less than subtle hint, which made me feel a tad uncomfortable, from a controller early on in this debacle which prompted me to follow your suggested procedure from that point forward.

However, it shouldn't be a controller teaching crews that they caused a problem via suble inuendos (and I shouldn't feel a tad uncomfortable for not doing anything percievably wrong....see my opening comment). I noticed recently that AMS have a NOTAM saying that this very situation should be declared on first contact. That sounds lke a better way to handle it. Otherwise you are relying on airlines to have overstaffed traing depts to write amplified SOP's for every scenario.

So either we struggle through it till the aircraft get modified, get all opators to write an SOP, or the busy TMA's could issue NOTAMS. I don't know which is best and there probably are more solutions. I'm not trying to say any paricular solution is right (or blame anyone), just trying to help give you some info on what I think is a very good question.

BTW please don't throw the 5kts FP deviation rule at me....thats being a bit pedantic....and non-constructive.

Cheers....Bomber

edited....spet your name wrong 5miles...sorry..stumpy fingers

[5milesbaby]

ManaAda, anything between 280kts and 320kts could be considered normal for most jets, anything less is acceptable, but a little nudge to say "we'll be going a bit slow" helps the plan. We do get quite accurate ground speeds on the radar display, however its not normality I'm on about, its when we have to trail using speeds.

Bomber, exactly what I was after and basically what I thought. We had an OPNOT produced warning us that in certain conditions, 737NG a/c may have a limitation due de-icing, and that is it. Nothing was added, and we are never to know if an a/c has been de-iced unless you up front let us know. The biggest shock was less than a week ago (and could show ATC nievity on this subject), when it was 20+ degs outside in glorious sunshine, and after a little hard vectoring the number one a/c THEN said he couldn't take the highspeed descent, and numbers 2 and 3 were further weived around and sailed into another sector to get the 10 miles in trail and still meet the height restriction.

I don't know what solutions would work for this, and think it'll just come down to what already happens. Hopefully word will do the full rounds and everyone can let us know early enough, if not, please don't get too upset by any extended sightseeing trips you may encounter, and excuse any puns you may hear, we aren't let out that often :} :ok: