Speeds
If you are outbound and told "no ATC speed restriction" then fly at your own speed if you are in Controlled airspace. If you are inbound you will probably have been given a STAR, the chart will give useful descent planning information and also a speed limit point. ATC may impose speed restrictions for traffic sequencing or to relieve overloading the holding stacks by absorbing some delay en route. Some operators may have a ground handling problem such as non availability of "gates"; this could be due to early arrival.......or an arrival before the end of night curfew...in which case the pilot may wish to slow to an uncharacteristic speed....... please tell us because a lot of control techniques depend on anticipated and normally observed performance profiles. ATC probably know as much about the performance capabilities of your aircraft [ from a purely ATC point of view] as you do after several years experience. BA are very good at giving plenty of notice of their speed needs e.g. they will ask for a "250 knot " descent......not a problem at all if given adequate notice, but may need a modest level change or early descent so as not to unfairly impede other traffic. Whenever a new type appears in service we tend to watch with interest for a while, and gradually the word gets round.