Air carrier flight crew reported during descent they lost control of aircraft due to having an encounter with a microburst. They took evasive action and regained control of aircraft.
Synopsis
Air carrier flight crew reported during descent they lost control of aircraft due to having an encounter with a microburst. They took evasive action and regained control of aircraft.
Narrative
Flight ABCD ZZZ - DFWMEL XX-XX for a seat implemented incorrectlyMicroburst encounter caused overspeed of aircraft in flaps 1 configuration andUncontrollable aircraft during escape maneuvers created a RA between our aircraft and a company aircraft.At the hotel the morning of Day 0 for the flight; I prepared for the flight utilizing a method; reviewing the deferred items.During this review; I noted a seat's airbelt was deferred utilizing MEL XX-XX. The maintenance procedures stated the seat was to be blocked and was not able to be sold. It also explained an INOP sticker was to be affixed in the cockpit.Upon reaching the gate; I confirmed with the gate agent that the seat should be block and listed as Do Not Sell". The agent confirmed that the seat was in fact blocked.As I briefed the crew; I found that the seat was not blocked; but another seat was blocked off.As I investigated further; I found MEL XX-XX was not complied with; and the whole balancing of the write up was completely incorrect. I called local maintenance; and reached out to Maintenance Control.Maintenance Control stated that the procedures were properly complied with; but the balancing documentation error was simply a "fat finger" error during entry. I explained that the keys were not located near each other; and I find it hard to understand how they were entered incorrectly in multiple balancing entities. In addition; the procedure for the application of this deferred item stated "Install INOP placard on panel blanking plate below ECAM Control Panel". This step was also missed.I was told from Maintenance Control that there was no way to fix the errors entered in the Logbook for the "balancing entries" from other people.In addition an INOP sticker with a number for a different aircraft was affixed to our aircraft. At this point due to a lack of confidence; I refused to move the aircraft until this blatant error was corrected. This was a complete failure of the maintenance procedure. The correction process caused us to depart late.Due to the item described in the section; we were now late. Weather in the DFW area caused the airport operations to swap directions (now to a south flow). We were the second aircraft put into holding on the arrival STAR awaiting the airport swap to be completed. After several turns in the hold; we were released and given a new clearance with a different STAR (BOOVE7).The ATIS changed from reporting winds calm to winds 180@10. On the arrival coming through 10;000'; we were located approximately abeam the airport. I made the "flight attendants prepare for landing"; announcement.As we checked in with the final approach controller; it was apparent he was task saturated with a class B intruder aircraft which caused him to alter the altitudes of all the traffic he was working. This caused an increase of unnecessary communications.For a majority of the arrival descent; we were VMC. Abeam the field; level flight and at 210 kts assigned airspeed; we were configured with Flaps 1. Both crew members visually noted and briefly discussed the inclement weather ahead and slightly off our left (away from our path and not on the approach corridor). I mentioned to the FO; I see rotation in these clouds. I attempted to request a right turn with ATC; however due to ATC being heavily burdened with the class B intruder aircraft; my request was delayed. Once we hit the microburst; the FO acted appropriately and altered the path of the aircraft. I informed ATC of our immediate need to alter our course; and I advised them to not send other aircraft in that airspace. ATC immediately directed other aircraft away from the area as we advised. During the escape maneuver from the microburst encounter; as we were regaining control of the aircraft from an instantaneous increase of both airspeed and an uncontrolled gain in altitude; the Vmo for our selected flap setting was exceeded.Once we regained control of the aircraft; we immediately began returning the aircraft to a normal flight state. We were given a turn to the south (parallel to the 18R runway); and due to the up draft and increased airspeed from the microburst; the un-commanded climb relocated us off of our assigned altitude. This caused us to generate an RA with a company aircraft who was also being vectored away from the weather we had just reported to ATC. Both aircraft successfully maneuvered safely and avoided any further complications. ATC gave us; and another aircraft; a new runway assignment; but inadvertently stated the new runway assignment was now 18R. He later restated the clearance of the correct "new" runway assignment of 13R.We remained in VMC conditions for the entire event; and the crew successfully utilized crew resource management skills. For example; when we were assigned the new runway; the FO clearly stated he was being overloaded and asked me to setup; verify; and brief the new approach. Once we were done; he briefly transferred the control to me so he could confirm and get himself back to being normal. This allowed both crew members to "reset"; and return to operating normally. Control was transferred back and we were cleared for the visual approach to runway 13R.As we configured for landing we were still experiencing some increased performance from the outflow of the microburst; but it was much more manageable. We were slightly above the visual flight path guidance; but were able to remain inside of the stabilized approach criteria. We landed and taxied to the gate with no additional issues. We contacted maintenance and made a Logbook entry documenting the event.In conclusion; like most events we've studied; it's never just one thing that causes an event like this.Three days prior; an error by maintenance; caught by this crew; caused the flight to be late. The late departure caused the flight to be stuck in holding due to the change of the weather; which in turn caused the flight to be the one aircraft vectored just a little too close to the outflow of a significant weather system; which caused this flight to become temporarily unresponsive and uncontrollable; which caused this flight to overspeed the flaps and caused this flight to be pushed off of the assigned altitude; which caused a RA event between two aircraft.I am not saying maintenance caused this series of events; but if we were not held up by the process to correct this carelessness; it is a good possibility none of this would have happened.Cause: Accurately completing the maintenance procedures.In the future; I would act more quickly in altering our course. I had never encountered this type of weather phenomenon in real life; and did not realize how far out the microburst could reach; at our altitude."
Second reporter narrative
On approach into DFW 18R we were following the arrival course. We had given the Flight Attendants Prepare for Landing" and the seatbelt chime at 10;000. We descended to 4000 feet on the downwind following another aircraft on approach into DFW. To our 12 o'clock was a cell. I just happened to look at the ground where I noticed what appeared to be a dust ring on the ground. To me this was indicative of a microburst. I mentioned this to the captain; but we both decided that we were high enough to not be greatly affected. Soon after; my captain noticed what appeared to be rotation in the clouds above us. At this point I had my hand on the stick ready to disengage and turn to the right away from the weather. My captain was trying to get a word in with ATC to ask for a turn. At this point in the flight we were Flaps 1; 210 KTS which; Meant we were about 20 KTS under VFE for the configuration. What seemed to be almost immediate; the over speed bell is sounding and we are over speeding at least 20 KTS with airspeed increasing. I immediately disconnected the autopilot; turned to the right away from the weather. Captain continued to work the radios while I attempted to wrangle the airspeed; I brought the thrust to idle. The aircraft then entered a climb. At some point; I did add some thrust back because in my mind; we were in a microburst. My concern was that we were soon going to experience a significant loss of performance and I wanted the engines to be spooled in preparation for an escape. I'm not certain how much thrust I left; but I think I had them about an inch or less from the idle stops. This could have been a mistake in regard to speed control; but as I said; I was expecting a severe loss of performance. We climbed about 1000 feet while trying to recover airspeed. During this time; ATC had turned us back to the south which put us in conflict with other arrival aircraft. We then had a climb RA which I responded to. By the time we had fully recovered from the event; we were at 6000 feet. We never experienced a performance loss associated with microburst. In my opinion it could have been because I immediately turned away from the weather or I was incorrect in assuming it was a microburst and it was an example of severe wind sheer. ATC then vectored us for the visual runway 13R. This approach brought us back towards the weather; but kept us at a much more comfortable distance. As we intercepted the localizer; wind sheered into a significant positive sheer which I believe caused us to remain high to recover speed. I had to level off again in order to gain control. This put us high on the glideslope. I was able to recover and have a decent rate at or under 1000 FPM at 1000 and speed was fully recovered by 500. We landed safely. No injuries. Proper maintenance entries in regards to overspeed were accomplished. Cause: I should have pushed harder when I saw evidence of what I thought was a microburst. I should have immediately disconnected and turned away from the weather despite being unable to get a word in With ATC.In my opinion there should be more emphasis on meteorological factors in our training. The cell was a U shaped cell; indicative of severe weather. While I remember learning this in the past; it was not on my mind at all. More training on weather radar depictions could have helped us avoid the situation completely. The weather was good for the arrival and turned bad very quickly. I was caught off guard by how quickly it turned. Finally; the use of speed brakes was completely out of my mind. Had I decided to use them; it could've prevented as much of an overspeed. I'm not fully convinced that it would've been the right move had we later experienced degraded performance in a microburst."
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.