As this is the season for run-ups here, I am wondering if there is a formal procedure or checklist for them and how the Captain announces them to the passengers.

There is one A380 which comes to CYYZ and sits on the ground for seven hours until takeoff, so it does run-ups almost every time.

I always do runups before takeoff. Pistons need it because of the mags, possible fuel problems, voltages, etc...

Turbines not so much. A 2 minute idle for the most part will tell you whats happening. Just watch the gauges.

 

Toronto is also a very good maintenance facility where they also service A380, especially when the layover is such. We don't do any run-ups with pax on board unless there is an abnormal.  A380 doesn't require any runup under normal conditions before t.o. During winter operations at certain temperatures might have a 30 seconds delay at a certain power before t.o. if you sit at idle for more than 5 minutes. Regarding the pax announcement, we keep it at minimum as possible to prevent any misunderstandings. Today it doesn't take too much for some nut case or "expert" to create some unnecessary speculations or even to scare passengers.

31 minutes ago, LRBS said:

Regarding the pax announcement, we keep it at minimum as possible to prevent any misunderstandings. Today it doesn't take too much for some nut case or "expert" to create some unnecessary speculations or even to scare passengers.

Absolutely agree , its often best to say nothing as very few  listen or understand anyway.

The other day I was leaving Boston in a snow storm at -3C and these RR trent 1000 engines on the 78 need a 30 second runup at 20% TPR for engine core deicing. I just checked with ATC we were clear behind and let them know what we were up to and stopped on the taxiway for 30 seconds. The little jet starts rocking around a bit at 20% TPR and it was quite loud for 30 seconds , then we returned to idle and continued to taxi.

I'd briefed the crew we were de/anti icing and done a quick PA to the pax about being sprayed with deicing fluid but didn't bother to explain the run up... no one said a word or asked any questions about it afterwards ,crew or pax.

@dmwalker There is a laid out procedure in the manuals yes, but it's simply a case of a certain N1 or TPR for so many seconds within a certain time period and below a certain temperature  with visible moisture, it differs on each aircraft type. There's no actual checklist as such. It's just covered in the pre flight briefing of things to cover and do. For example taxing through slush we'd also keep the flaps up until reaching the holding point.

Edited February 23, 20224 yr by jon b

So the decision to do a run-up is made while taxiing? They never seem to say anything to Ground Control until well on the way to the runway.

This discussion will start during the briefing and be finalized after the last met report and actual wx conditions. It can be before taxi, during taxi, or just prior line-up to request the 30 seconds to hold before t.o roll. There are many considerations to be taken into account and sometimes what we sought during the briefing was appropriate might change at the last minute.

Regarding ground control, we will always coordinate with them if we run engines above ground idle to have the area clear behind us due to jet blast.

Unfortunately, it is very difficult to have a correct answer to your inquiry without all the details and different airline/airport procedures.

1 hour ago, dmwalker said:

They never seem to say anything to Ground Control until well on the way to the runway.

If it's somewhere busy then I usually mention it to ground while taxiing and ask if they can pass it on to tower we need 30 seconds static for their planning.

You can imagine if they give you a line up and then an immediate take off clearance as they have someone on short finals then you say sorry I've got to wait 30 seconds they wont be happy.

At quieter airfields, maybe like CYYT runway occupancy isn't as much of an issue.

On my example at Boston they were departing on 09 and arriving on 04R which cross each other so the easier option was to get the 30 second core anti ice run out of the way on the taxiway, the fan deice run up on the 787 is only 2 seconds static run up at 50-55% N1 so not as much of an issue. On the 747 though it requires a 30 second static run up at the start of the take off roll at 60% N1 and also the same run up every 30 minutes when you're in icing conditions , that's some times more tricky to accommodate as you'd imagine 60% N1 on one of those things creates quite a lot of jet blast.. it's a proper aeroplane.    

 

Edited February 23, 20224 yr by jon b

Apparently, the A380 run-up is done on two symmetrical engines at a time. Is it the same for the B747 or is it specific to the A380?

On the 380 we do it on all engines at the same time, as we did on the 747. I'm quite surprised to hear that, but again, each company has different SOPs.