Engine Run Ups

[MTBUR]

Everyone knows when flying piston aircraft that run up checks are important, and back at flight school I was always taught it's something you do in between engine start and takeoff (of course!). But I've seen a few places doing runups first thing in the morning, then taxiing back and shutting down, getting passengers, starting up and going straight to the runway. Subsequent flights later in the day have no runups immediately before.


Am I the only person who sees this as being a bit strange? During that next shutdown or start sequence couldn't a problem arise and subsequently go unchecked, especially in outback Australia where aircraft engines get quite a battering with heat?

Cheers!

[taxistaxing]

:eek: That sounds strange to me, and radically different to the way I was taught!

I was always taught the only thing you do before the first flight of the day, that you don't need to do subsequently, is check for water in the fuel tanks that may have accumulated over night.

My instructors have always told me to do a runup before every takeoff, even if you do a full stop landing and taxi straight back to the hold to takeoff again (e.g. when you're doing night rating circuits). As you say, the point of a runup check is to ensure the engine is operating correctly before the most critical phase of flight.

I have seen pilots at my club start up, taxi out and takeoff without a runup but certainly wouldn't be comfortable doing that myself (or even flying with a pilot who thought that was acceptable).

[Ka8 Flyer]

Well, if the runway is long enough, where's the real risk?
You do the runup on the first leg to verify both mags are working.
During a runup you'll only notice problems if they arise shortly after setting power - you'd have the same outcome on the take off run as well well before reaching Vr.

[barit1]

Wimps.

Runups on ordinary landing gear are a piece of cake - when you consider how it is done on skis or floats. You'll find your brake pedals pretty much -- ummm, useless.

[taxistaxing]

Well, if the runway is long enough, where's the real risk?



:rolleyes:

I know there are some idiots out there but that takes the biscuit. I can only hope to God you're not a pilot with an attitude like that.

So just how long do you think is "long enough"? What if it's a 600m strip with houses at the end? What if you're taking friends or your girlfriend flying and the engine quits at 500 feet and you have nowhere to go? Imagine how you'll feel in the final seconds before impact, responsible for those lives!

Or do you think you know better than the guy that wrote the checklist?!

Run ups are done to ensure everything is working okay when you are about to depend on it the most, and they take all of 30 seconds to do! Coming on here and questioning that is pretty bloody stupid. You're checking for mags, t's and p's and no carb-icing. All pretty crucial in a SEP just before you firewall the throttle and put your life in the hands of that engine.

Flying is risky enough at the best of times, so anyone who doesn't try to minimise that risk deserves everything they get, in my view.

All I know is I'm glad I'll never be flying with you :ok:

[Machinbird]

I was always taught the only thing you do before the first flight of the day, that you don't need to do subsequently, is check for water in the fuel tanks that may have accumulated over night. I would call that statement into question. If you take on fuel, it is always a good idea to check the sumps/ low points, and that goes for jets too.

It helps avoid those unexpected moments of quiet contemplation.:eek:

[AdamFrisch]

Well, a run up is important first thing in the day. After you've already flown once, I normally just do very brief mag checks and prop checks on my taxi out for the next flight. On long cross country flights, I periodically check the mags in flight when I can remember to do so. Only time I redo the full run up if I've already flwon is if I've shut down and parked the aircraft and had it out of sight for a couple of hours and/or the engines have cooled down considerably.

[Ka8 Flyer]

@taxistaxing:

calm down. I agree with Adam. I never said that you should avoid runups, I'm just questioning the reason to do it when you have already flown a bit, the engine is warm and all indications have been normal. How high do you think the probability is going to be that the run-up is going to reveal something that won't show up during the first stages of the take off run?

And by long runways, I mean in excess of 3000ft / 1000m.

[Agaricus bisporus]

Well, on that basis why bother with checks at all. After all, it all went fine last time...

As this forum is called the Professional Pilots Rumour Network it seems a shame we have to suffer remarks like that. They belong elsewhere. Perhaps on the Jackanory website...

[Ka8 Flyer]

Well, let me ask you something else then, this time more related to professional aviation.

Say, on a 737 NG:
Do you perform an engine / APU / cargo fire test on every turn around?
Do you test the configuration warning before every take off?
Do both PF and PNF check the flight controls before every take off?
Do you perform the EGPWS / TCAS / STALL / Overspeed test on every turn around?
Do you do a light test on every turn around?

For every european operator I know, the answer is no to all above...
(And obviously, the answer is yes to all above for the first flight of the day)

[WallyWumpus]

Ka8. Nearly my friend. The following from Ryanair, the largest European operator.....



Say, on a 737 NG:
Do you perform an engine / APU / cargo fire test on every turn around? No.
Do you test the configuration warning before every take off? Yes, three separate times before EVERY flight.
Do both PF and PNF check the flight controls before every take off? Yes, absolutely!!
Do you perform the EGPWS / TCAS / STALL / Overspeed test on every turn around? No.
Do you do a light test on every turn around? No.

For every european operator I know, the answer is no to all above...
(And obviously, the answer is yes to all above for the first flight of the day)

[bugsquash1]

I use to do run-ups Etc early at proper power to ensure no problems. Then with passengers on board a lower rev run-up to ensure mags OK.
Not so bad for nervous flyers. :ok:

[lynn789]

an engine runup is something every jet airline passenger could recognise and they simply arent done anymore in australia.
your only runup is the taxi out to end of runway:ugh:

[MTBUR]

I never said jet aircraft, I said piston as per my first post. In regards to the daily/crew change tests stated above, of course they are daily/crew change - the aircraft types specify that and have the technology to show a failure.

But for piston, with no technology other than the runup to show a busted magneto, fouling, etc, I think you're mad to run up, shut down, come back a few hours later and fly with no further check. Older piston engines are ugly on startup, and I've had cases where thats messed with the mags (funnily enough after a mag check in the hangar). If I had just said I'd already flown it that day lets fly who knows what could have happened.

[Krystal n chips]

" take on fuel, it is always a good idea to check the sumps/ low points, and that goes for jets too.

You may care to review this statement.

If you do a water drain check, immediately after fueling it's an excercise in futility as the fuel entering the tanks, will still be happily sloshing around and with it any water.

Hence the reason, as an engineer, it was always done after as much down time as possible....... to allow any water to sink to the botton of the tank and thus with the fuel in a stable, rather than turbulent condition.

[AerocatS2A]

an engine runup is something every jet airline passenger could recognise and they simply arent done anymore in australia.
your only runup is the taxi out to end of runway

Eh? There is no run up for a jet. Anything a jet passenger thinks is a run up, isn't. Maybe you are getting confused by setting power on the brakes before take-off on a limiting runway?

[Piltdown Man]

Going back a few years I can remember that we only did a full run-up on the first flight of the day. For every subsequent flight we just made sure each mag was working. And, horror of horrors, I also remember having to lean the engine on hot days to get the required RPM/MP. As for jets (and turboprops), I've never done a water drain and runups are little more running at a high power setting just before departure to detect and/or shed ice.

PM

[Ka8 Flyer]

@ Ecam,

I deliberately mentioned the NG above because there are lot more automatics on the bus, such as the takeoff config memo on the ECAM. Regarding flight control checks, I guess everyone is going to be doing a full control check after the maintenance foul up at DLH where the sidestick roll axis got reversed.

@ Wally,

I'm surprised to read that. Is there a specific reason why you test the config warning 3 times? As to the flight controls, the outfits I'm familiar with will have only the PF test his/her controls when it's not the first flight.

@ All,

I just want to emphasize that what I'm questioning is the procedure of doing run-ups before every takeoff IF the PIC has been sitting in the aircraft the whole time. taxistaxing mentioned a required runup after a full stop landing and taxiing back to the runway for another take off. This would mean, a touch and go will be inherently 'much more dangerous' - or do you perform a runup in that case as well? :ok:

Trust me, I'm not a bold pilot and don't take unnecessary risks. Aviation is all about risk assessment and it's just my opinion, that there are cases where I don't think a runup is necessary. But that's all it is - my opinion.

[taxistaxing]

I just want to emphasize that what I'm questioning is the procedure of doing run-ups before every takeoff IF the PIC has been sitting in the aircraft the whole time. taxistaxing mentioned a required runup after a full stop landing and taxiing back to the runway for another take off. This would mean, a touch and go will be inherently 'much more dangerous' - or do you perform a runup in that case as well? http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/thumbs.gif



Thanks for the clarification, K@8. In hindsight perhaps my first response was a bit strongly worded. Apologies if any offence was taken.

The reasoning behind the full run-up in the circumstances I mention is that the engine has been at low RPM for a few minutes during the taxi back, with carb-heat taken off as part of the post landing checks. Therefore it's sensible to at least check for carb-ice before applying full power. Since I fly a SEP and the "full" runup is only setting 1700rpm, T's and P's, carb heat and mags check, it makes sense to do the whole thing.

I'm also doing the night rating at the moment where the consequence of EFATO is certain death, which concentrates the mind !!! :sad:

As you say it would be difficult to do any kind of run-up check on a T&G :ok:. But then again during a T&G you go straight from idle throttle with carb-heat to full power so in theory there is no time for any carb icing to form. I suppose you could say a T&G is less dangerous than a full stop landing followed by another takeoff, on this basis.

[WallyWumpus]

My understanding is that if the SOPs call for something 3 times, the chances of it being done at least once are very very high. The big underlying fear is starting the take-off roll without flaps.

[Mach E Avelli]

While I personally would rather not put an extra cycle on an engine by starting, going out to the run up bay then returning and shutting down prior to boarding, there are often valid reasons for this practice. For example, if the aeroplane has to be relocated from hangar or tie down to the terminal, the cycle may as well be used for the run up. Or the runup bay may be in an inconvenient location, or subject to waiting times at peak hours.
As someone points out, there could be a difference between what is required on first flight of day and subsequent short turnarounds. That policy is up to the operator to establish with the regulator. And often will have to reflect what the flight manual stipulates.
Another argument: Just because it works now has no bearing on how it will work in five minutes time (e.g. testing landing lights achieves nothing except to shorten the life, as like so many devices, they usually have a finite number of cycles between failure).
If a piston engine is running smoothly and makes power during the intial take off roll, there is no reason to suspect problems.
Some operators may also call for a mag check and fire test prior to the last shutdown.

[Willit Run]

I'm gonna stick my neck out here;

on piston aircraft, oil temps often take time to reach before take off. Most piston aircraft do not have air conditioning on the ground. So, doing a pre, first take off of the day run-up, to get oil temps up, check mechanical integrity, (to give time for a possible repair, or aircraft swap), and just make sure everything is up to snuff, isn't a bad idea. Engine start cycles are not tracked on piston aircraft, (as far as I know) so thats not an issue.
A few years ago, when I was a DC-6 Engineer, we would often go out early when it was cold, and get the engines warmed up, and to try and stave off an unpredictable delay. there are a lot of things that can go wrong on a big piston to cause a delay; but when things have worked and are warm, they will most likely keep working. Nothing in the mechanical world is certain, but we have learned through experience, what works and what is less likely to.

On jet aircraft, doing a pre-first taxi run-up on a really cold day, or if the plane has just come out of a maintenance check, or if the plane has been sitting for an extended period of time, is a good idea.

As far as the "checklist comment, and who might have written it", that has no bearing on the matter. There is an incredible amount of idiots who have kissed their way into management positions, that have no business making checklists or making any kind of procedurally based decisions. Anyone who has been in this business longer than 5 years have seen checklists changed in one direction, and then 3 months later changed back, because it was a really stupid change.

[VP-F__]

when working for my previous operator flying a light twin piston we routinely did a full power check upon leaving the hanger in the morning, then shut down to collect our pax. This was so that the aircraft could be assessed as servicable keeping inconvenience to a minimum if otherwise. After that the checks would be reduced to engine checks with only a full runup being done every two to three sectors but a mag check always prior to departure. This was considered acceptable for a few reasons. Firstly our turn around times were short, rarely more than ten minutes shut down so the engines remained warm. More importantly the engineering standards on the aircraft were fantastic. At takeoff power there was never much out of sync on the engines and the engines always ran up at the same speed. It would easily be recognised if there was a power problem very early in the take off roll. As a point of reference the accumulated fleet hours are probably around 100,000 by now and have only ever had to carry out three inflight shutdowns.

[Big Pistons Forever]

Run ups are done to ensure everything is working okay when you are about to depend on it the most, and they take all of 30 seconds to do! Coming on here and questioning that is pretty bloody stupid. You're checking for mags, t's and p's and no carb-icing. All pretty crucial in a SEP just before you firewall the throttle and put your life in the hands of that engine.

Flying is risky enough at the best of times, so anyone who doesn't try to minimise that risk deserves everything they get, in my view.

All I know is I'm glad I'll never be flying with you :ok:

This thread should really be in the Private aviation column as the tech forum is really meant for professional pilots dealing with issues in commercial aviation.

You sir have not idea what is appropriate for the commercial operation of piston engine aircraft. I can say as a professional pilot that the pretty much universal practice is to do a full runup at the beginning of the day and then only do a runup if there is cause for concern . The logic is that pretty much everything that the runup will tell you will be observable while flying on the previous leg and therefore normal operation on the run in obviates the need to do a runup. To imply that every pilot is acting unprofessional for not doing a runup before every flight speaks more to your lack of knowledge than anything else...........

[taxistaxing]

Big Pistons, I'm commenting from the perspective of a low hour ppl, flying the simplest of SEPs, as the OP may have been. I freely admit to a lack of knowledge of commercial ops but in private ops I would question the wisdom of a low hour ppl such as myself omitting run ups which take no time at all. Or would you advise otherwise?!