Based on flight simming, it seems that overspeed happens on occasion when at cruise speeds. I was curious when this happens to real commercial pilots. I know overspeeds need to be reported, but how long can one happen before actual structural damage occurs? How often do overspeeds actually occur? How are they handled? Are there any pilot penalties for encountering an overspeed?

Based on flight simming, it seems that overspeed happens on occasion when at cruise speeds. I was curious when this happens to real commercial pilots. I know overspeeds need to be reported, but how long can one happen before actual structural damage occurs? How often do overspeeds actually occur? How are they handled? Are there any pilot penalties for encountering an overspeed?

I have a moderate amount of experience flying a 737 classic and I've never had or seen an overspeed warning. I presume they are very rare events, but we do fly near to VMO/MMO on fairly regularly and as such we get near to overspeed situations on occasion.To specifically answer your question, the best thing is to know when an overspeed is likely. The most common cause on the real 737 is VNAV PATH descent mode. It can get to the barbers pole if you're not paying attention as it will always adjust speed to maintain the descent profile, if you're high it will dive to get back on it. Such as the 737 is, its automation can take a while to correct itself exacerbating problems. As a result I reckon I have chosen to manually intervene when getting uncomfortably close a couple of times but usually change the autopilot mode to or use speedbrake to prevent it.Manual intervention is for when automation isn't correcting as promptly as you would ideally wish. By manual intervention one can either disconnect the A/P and A/T and manually adjust pitch, but from experience I think it is best just to gently increase back pressure on the stick and the autopilot will automatically trip into CWS pitch mode. Then select CMD (full autopilot) again once when the rate of descent has been reduced. If I anticipate getting too close to the barbers pole I switch to V/S (vertical speed) and simply select like -2000 FPM, this will always gently decelerate the aircraft. When I say close to the barbers pole, the image is when the ASI needle just starts to overlap the pole.The main reason for unexpectedly finding yourself near VMO/MMO is usually a high speed descent within say 5-10kts of VMO/MMO with stronger than expected tailwinds. But a mistakenly hasty direct to in the LEGS page significantly reducing track miles to run can cause problems too!Have a play with 737 PIC, although not 100% accurate, it is a pretty darn good representation.A half decent pilot will ensure any infraction (overspeed, whatever) is reported promptly, and a half decent airline will not punish but encourage detailed and honest reporting and seek to gain information and experience in order to formulate and strengthen its training practice and operating procedures.

Overspeeds on descent are not actually that rare, they used to be a potentially very common possibility on the Classic Boeing 737 before the engine inlet spinner was modified on the CFM to dissipate water better and minimise ingestion. Prior to that, Boeing SOPs stated that a minimum throttle setting had to be maintained on the descent through clouds in order to prevent a flame out.However, to quantify things somewhat, there are serious overspeeds, and there are also not very serious overspeeds. Typical overspeed limits for an airliner that would require maintenance actions, would be anything that is 20 knots or more over VMO, or .02 Mach or more over, although that varies for different aircraft. Below that, an airline crew might just get a few snotty remarks but no action taken against them. More serious overspeeds can result in demotions, fines levied on wages, or even being fired if it is a serious infraction. In some cases, the crew might have to take a remedial check ride, additional training or some such. Some airlines are more strict than others where this sort of thing is concerned.The reliance on VNAV by a pilot who might place too much trust in the FMC's capabilities to control speed on a descent, has led to overspeeds on plenty of occasions, so it is really the job of the crew to monitor that properly in order to see that action is taken quickly if the speed trend pointer starts indicating that an overspeed might happen. When they don't do that, a penalty of some kind is certainly a possibility.Strictly speaking, like everything else in engineering, the limits the test pilots place on airliners means that a minor overspeed will be well within the limits of what the aircraft can actually handle without any detriment at all, so a minor overspeed is in fact a non event in reality, although the chief pilots and maintenance chiefs at some airlines might not be so benevolent as to see it that way, since it really should be avoided.We have all seen the famous footage of a Boeing 707 doing a roll when flown by Boeing's test pilot, which is in fact not a very high G maneuver, but even so, it does indicate that airliners are quite a bit more resilient than might be imagined, thus, a large overspeed may not necessarily damage an aircraft that badly, but it almost certainly will put stress on the thing and potentially shorten its useful life. For example, a Boeing 727 once broke the sound barrier after the pilots cocked up when messing with the flaps in cruise; the aircraft lost a slat, causing it to roll and then stall out into a dive. In the dive, it went past Mach 1, but apart from some rivets having popped and some slight panel bends, the aircraft was reasonably unscathed for a trip that was well past its design limits. There is some suggestion that a Chinese B747 may also have busted Mach 1 after a similar occurrence a few years ago following the loss of an engine in cruise, but on that occasion, the aircraft was fairly seriously damaged, losing quite a lot of the tail surface area and quite a few panels, although that too made a safe landing.The problem with an overspeed, or at least attempting to prevent one if it is approaching, is that the wings will be quite well flexed, and in such a situation, deploying the spoilers will stress them a lot and might not even be permitted, so it's not always an option to use them at high speeds. As noted above, quite a few 737 pilots have resorted to dropping the gear on a descent in order to keep the speed down when they had to maintain a bit of power on the engines, but again, you can't drop the gear at very high speed either, so that's not always an option, and certainly not at cruise speeds, thus the pitch and throttle settings are invariably the way to prevent one from occurring, and the sooner the better.If you want to see the kind of stress a serious trip to the wrong side of VMO can do, take a look at the footage of the Boeing 767 which was flown into the World Trade Center on 9/11 (the second attack). It's fairly unpleasant to watch that footage, but if you do, you can see that the wings are very seriously bent upwards just before the impact with the tower, but of course, the terrorists in the cockpit were hardly concerned about stressing the aircraft. You can probably find footage of that on youtube, although you might have to wade through some ridiculous conspiracy theories in doing so.In Flight Simulator, the wind shift one experiences as the weather updates from a download can make overspeeds in cruise more common than they would be in reality, since you often get complete swings in wind direction and massive changes in wind speed that would be unlikely in reality, which is why minimising that effect in FSUIPC is not a bad idea. You should also be aware that not every airline cruises around with the speedo needle half a millimetre away from the barber pole limit; often the cruise speed will be well under what is actually possible, in order to improve fuel economy.Al

Based on flight simming, it seems that overspeed happens on occasion when at cruise speeds. I was curious when this happens to real commercial pilots. I know overspeeds need to be reported, but how long can one happen before actual structural damage occurs? How often do overspeeds actually occur? How are they handled? Are there any pilot penalties for encountering an overspeed?

Are you using real world weather when simming?One of the really big culprits of overspeed warnings when at cruise in a simulator is drastic changes in wind speed or direction. In the real world, such instant speed and direction differences are not usually seen. If the wind direction suddenly changes in the simulator, you might get a momentary overspeed warning as the airplane adjusts to the new winds... the airplane isn't going any faster or slower, but suddenly the relative wind changed enough to trigger the overspeed. While I am sure the above messages are correct about overspeeds during descent, it is probably much more rare for an overspeed to occur during the cruise phase of flight. Such instant and drastic wind direction changes just don't happen quite like they do in the simulator. -Greg

All good information, gents, and I really do appreciate it. Most of the overspeeds I encounter in simming are indeed during cruise and only after AS has updated weather. Combine this with the closeness to the barber pole (which I'm trying to figure out how to reduce to save fuel economy as suggested earlier) and it's pretty clear that a complete shift in winds will push me past this limit. Usually, however, it's only slightly above the pole and not for long as I usually sit with my AC during the whole flight (unless it's transatlantic or longer than 3 hours) and am able to correct.