EMB ERJ 190/195 ER/LR
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation - Altitude Crossing Restriction Not Met; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Clearance; General Maintenance Action
Procedure; Aircraft; Human Factors
During our descent; we were assigned a crossing restriction from Center. The First Officer (pilot flying) properly put the restriction into the MCDU; we verified it; and activated it. I don't recall if we briefed the top of descent because of the rather rapid sequence of events that followed. This all happened while I was making some requests in the ACARS (I don't recall if it was weather; which was changing rapidly; or if I was requesting the changeover). Simultaneously; I attempted to change the volume on my Audio Control Panel (ACP). I noted it wasn't operating properly and I could make no selections on it. And I no longer could use my interphone or make calls to ATC through my headset. In an attempt to at least hear ATC; I turned on the First Officer's (FO) speaker (mine wasn't working either). Having never before seen a problem like this; I wasn't sure if it would be temporary or not; but in hindsight it is clear the ACP had failed at this point. I was able to verify that later while running the QRH.At this point I noticed the aircraft pitching over to begin its descent toward our crossing restriction. By the time I looked up at the PFD; I saw our speed was about 315 knot; trending toward the barber pole and the magenta path was below us. The airplane was trying to dive to capture the path. The FO noticed this as well and attempted to intervene by using the speed brakes. That exacerbated the problem by pitching the nose over farther (and adding a couple of knots to our airspeed before the speed brakes could take effect). Our airspeed momentarily changed from yellow to red (I saw approximately 322 knots; or a 2 knot overspeed). At that point I intervened using the Touch Control Steering (TCS) button and pitched the nose up slightly. This all happened rapidly due to the aircraft automation ignoring Vmo and the tailwind we had. Once we got the aircraft back on profile and we were in the green again; I told the FO to request relief from the crossing restriction because it didn't look like we could make it. Once we leveled off; I pushed the backup button the ACP; consulted the QRH; and was able to resume working the radios.To be clear; the FO did nothing wrong; leading to my intervention. My experience on the aircraft allowed me to quickly diagnose the problem and remedy it; without time to communicate that (under circumstances that limited communication due to the interphone being inoperative) with a rapidly impending over speed.Incidentally; the QRH procedure for an inoperative ACP is essentially useless; and probably one of the worst written QRH procedures for the E190. It directs you to push the backup button; however it doesn't explain any of the ramifications of pushing that button; which are applicable to operating the aircraft (you are hard wired to COM1 with a #1 ACP failure; cannot make PAs; cannot use the interphone with the flight deck crew; and you cannot call the Flight Attendants (FA) through the interphone). Furthermore; the QRH procedure title could be better worded to use 'Audio Control Panel' or something similar. It took me several attempts to find it using the search function on my iPad; after failing to find the checklist in the QRH (I recalled there being one but wasn't positive where it was. The QRH checklist is titled 'Loss of Communications' and did not stand out when I was looking through the Alphabetic Index in the QRH - I guess because it did not seem applicable. I think having the name of the affected panel would have been helpful).After arriving at the gate; I wrote up the overspeed and the ACP failure. I also wrote up that the FO's PA was not working properly; after the FAs reported they could not hear his PA during our arrival (after the ACP failure and subsequent holding).I'm not sure I could have done anything differently to prevent this particular incident; but; as always; there are important takeaways. I will personally continue to be very cognizant of crossing restriction top of descent briefing for both myself and FOs. I always verify the TOD in the MCDU and do mental math. I think in this case I got task saturated when the ACP failed. When I saw the aircraft beginning to over speed; I intervened and made sure to get the aircraft and crew back in the green before dealing with a rather innocuous non-normal issue (it was minor but hampered communication to ATC for me which is tertiary to flying the plane and navigating). I also believe we got the crossing restriction very late; which does not allow the crew to adequately prepare for it. If I see crossing restrictions that might be difficult to make due to high tail winds or any other reason; I make sure to mention that to new first officers and discuss why it might be hard and how to prevent any problems during the descent.New FOs are usually very knowledgeable and cognizant of FMA changes as well as both lateral and vertical navigation modes. My FO was no different on this trip; however it seems new FOs have not seen this type VNAV descent where the autopilot will dive to attempt to catch the path from above; regardless of speed. It would probably be helpful to highlight this unique automation challenge in the simulator during initial training or Operating Experience.Furthermore; the speed brakes are not a good way to try to slow the aircraft down when it is rapidly approaching an overspeed condition. Because they cause the nose to pitch down; and the auto pilot and auto thrust is slow to respond; it can exacerbate the situation instead of resolve the problem at hand. This is another item that could be useful to address during initial training. I know it's something that normally comes with experience flying a certain type of aircraft; but because we fly so many Optimum Performance Descents (OPD) and operate the aircraft at idle thrust in descents so often; it limits our options on many descents. It is often easier; quicker; and more effective to just use the TCS button or turn off the autopilot to prevent an over speed.During the flight; I would have spent much less time figuring out what communication I could accomplish if the QRH procedure was written more clearly. That troubleshooting distracted me during an important phase of flight (arrival and eventually holding as well). Pilots expect clear QRH procedures so we can focus on flying the plane instead of troubleshooting.ZZZ Center almost always gives late clearances to crossing restrictions. Often we are within 5 miles of the top of descent for a 3.0 degree path when we receive the clearance; forcing pilots to rush (and not allowing for shallower descent angles that can act as barriers against a high workload descent). I'm not sure if it's because of airspace borders or bad controlling but because there is often a tailwind on ZZZ arrivals; the restrictions can be very difficult to make without using speed brakes and task loading pilots to focus on the restriction. The more difficult restrictions are usually after ZZZZZ Intersection. When we are familiar with the problem; pilots can guard against it but many new FOs haven't experienced this airspace or arrival often enough to be aware to guard against it.Finally; the aircraft automation should default to Flight Level Change (FLCH) when trying to catch the path from above; not dive for it without regard for speed. I know that would be a significant change on the aircraft logic; but it should be considered by Embraer/Honeywell in the future for their software development.
EMB190 Captain reported an Audio Control Panel failure at the same time his relatively new First Officer was attempting to follow a descent path with a strong tail wind. An overspeed resulted as the Captain struggled to find a QRH procedure for the Audio failure.