Very slow approach - when to announce to help ATC?

[Andy Rylance]

The other day the following happened:

"xxxx turn now 240 degrees, when established descend on the ILS."
"yyyy need you to slow right down now company traffic ahead and you are catching up fast. yyyy what is your speed now?"
"220 now slowing"
....
after xxxx got established
"yyyy still need speed right back, what is your speed now?"
"185 and coming back"
......
"yyyy when establised descend on the ILS"
"yyyy is established"
.......
"yyyy STOP the descent now, this is not going to work. Turn immediate right 360 degrees. Height now 2,500ft please. Going to bring you around on a orbit to come back for the ILS"
......
"what happened? Very annoying..." says yyyy
"When xxxx turned into wind he slowed to what appeared to be only 110 knots ground speed, much slower than I expected..."

Anyway WHEN is expected that you should announce to ATC that your aproach speed is going to be very slow and what is "very slow"? Is it happening as much as it should? Are there any agreed protocols...?

A

[foghorn]

I'm not gonna comment on the scenario above, but to answer the question in the title, it's best that you inform ATC as soon as is practical. To make sure you are telling the right unit, a good rule of thumb in the UK is to do it on the first frequency with callsign Radar or Director (as opposed to Control).

[Nimmer]

Sounds like poor controlling to me, use speed control, then you always know what speed is being flown. If a pilot wishes to fly a differnt speed they have to ask!!!!

[wadi racer]

I agree with Nimmer, if you want a specific speed as a controller then specify it........

Wadi

[loubylou]

As stated - as soon as you're on the approach radar freq.
I would define slow speed where the crew are unable to fly the standard speeds - ie 180 base leg/ 12-8 dme and 160 to 4 dme.
To announce this as the turn onto the loc is issued is too late and I would break that aircraft off as the sequence has been set up at this point.
I agree that the controller should've used speed control - but then maybe he did and the crew decided that that didn't really apply :p in which case I would have broken that one off !

louby

[Geffen]

If under speed control, fly the speeds. howwever if you are going to be unusually slow for type inside 4 dme. Tell approach ASAP, they will allow more space behind for catch up.

[cb9002]

Hmm, I think you gentlemen are all assuming that we are talking about commercial traffic here.

It could have been two trainers? We get citations on approach flying 130kt IAS, which can easily translate to 100 ground speed.

And as for standard speeds, ever tried asking a seneca/chieftan to fly 160 to 4?

[Another_CFI]

I have flown Senecas into both Glasgow and Edinburgh on a few occasions and have been asked to maintain best speed and report the speed. As long as the cloud base is at least 1000ft the Seneca can be flown maintaining 160 to 4 so I will increase speed for the approach and maintain 160 to 4. Then once inside 4dme and visual a momentary excursion above the glide slope enables the aircraft to be slowed down to lower gear and flap.

[cb9002]

Fair enough, but would you ask one of your IR students to do that?

And what would be the likely result if one tried it on a 170A or an exam?

At my place, I usually get PA34s at 100kt IAS the whole way along the approach.

[Denti]

I flew senecas only during training on airline procedures and syllabus. We used to have a so called "high speed approach" procedure to do at least 150 to 4, granted its not 160 but much better than chugging along at 100kts.

Got surprised lately by a controller who first asked me what my minimum clean speed was before ordering me to fly it. Good thing, since the 737NG doesn't have fixed speed schedules anymore and our 700s are usually quite lightweight with min clean around or below 190.

[OA32]

Speaking from experience, it's better to know the speed sooner rather than later as it then gives the option of using vectoring to start and then speed if required. There's 2 things my OJTI always says:

1. If its slow make it first or last, don't put it in the middle of a sequence.

2. Speed control is no substitute for good vectoring.

Of course if all the a/c are capable of the same speed it makes things a lot easier, its when you get one that isn't that backs up the traffic sequence and may even result in a few having to be taken through the centreline for spacing no matter how much speed you use. Which begs the question from a pilots point of view, is there a set procedure for how quickly you can reduce the speed as some seem to do it quicker than others???