EMB ERJ 145 ER/LR
Troubleshooting; Human-Machine Interface
Aircraft Equipment Problem Critical; Deviation - Speed All Types; Inflight Event / Encounter Weather / Turbulence
Flight Crew Took Evasive Action; General Declared Emergency
Weather; Aircraft
We were holding 50 miles south of our destination at 36;000.  We were IMC and interior windows were covered in frost; we were waiting for the weather to move north of the airport before descending and continuing the approach.  Once we began to descend we noticed the airspeed indications began to drop from 200 knots.  While descending through FL320 the aircraft began to buffet and to pull the nose lower.  Captain disconnected the autopilot; pulled the aircraft nose up and the buffet stopped; as the Captain continued the descent we noticed the airspeed continue to reduce for all three indications; I declared an emergency at this time with Center.  At this time the altimeter on both PFD's failed.  After a few moments the First Officer's altimeter began working and I took control of the aircraft.  At this time I began a more aggressive descent looking for warmer temps since the pitot static system appeared to be frozen.  Once descending through about FL190; both airspeed indications and altimeters appeared to operate normally.  I continued to descend the aircraft for approach.  Once on LOC I asked for my wiper and it would not operate; so I transferred control to the Captain for landing.  Landed uneventfully; entered malfunctions into the logbook.It is possible the pitot static system has a design flaw.  This event was described to me by another EMB-145 Captain.  He also had all airspeed indications fail; not sure if the altimeter also failed.  We were lucky that the aircraft didn't stall or overspend and cause structural damage. The FAA needs to take a look at the pitot static system of this aircraft. It might need to be redesigned. It is possible for a serious accident or crash.  There is no QRH for this failure.  I have serious doubts to the safety of this aircraft.
During descent in night IMC; we lost all airspeed/Mach indications and altitude indications on both PFDs as well. We had been IMC most of the way; deviating around thunderstorms the whole way; and we ended up holding for a bit; waiting for a strong line of thunderstorms to move off the airport. Once they cleared the airport; we began our descent from FL350 as we headed towards the airport. We'd been airborne for approximately 2 hours at that point. Shortly into the descent; I (Captain; pilot flying) noticed that my airspeed was decreasing; even though we were descending steeply. A crosscheck with the First Officer's airspeed showed his matching mine and decreasing also. The standby airspeed display on the ISIS was not decreasing at the same rate as ours; but was also reading erroneously slow and decreasing. All three instruments continued to get worse as we descended. Ultimately; all three airspeed indications reached zero; at which time airspeed and altitude indications on both PFDs were replaced with red X's. At this point; having no airspeed/Mach information at all; and only one altimeter (the ISIS; also reading inaccurately); in night IMC with thunderstorms in the area; we declared an emergency and queried Center as to the nearest VFR. We were told ZZZ was marginal VFR and looking to improve as the thunderstorms moved off to the east; so we elected to continue there. We did our best to fly attitude and a power setting during our descent; but we believe we exceeded the Mmo limitation; as we began to experience a sharp; rapid; 5 degree left - right rolling moment that we interpreted as Mach buffet. I immediately disconnected the autopilot and pitched up with the power at idle to slow down. A slight tucking tendency was evident as well once I disconnected the autopilot; both the buffet and tucking tendency disappeared quickly as we slowed. We continued our descent with frequent crosschecks with ATC for both altitude and groundspeed readouts (to cross check with our own groundspeed readout); using the groundspeed and what we knew of the winds aloft to estimate our TAS and therefore IAS. Eventually (I estimate around 15;000 feet) the First Officer's airspeed and altitude indications returned on his PFD; and the ISIS began to indicate airspeed again as well. The two instruments disagreed with each other and neither seemed entirely accurate at first; but were at least indicating trends. At that point I transferred controls to the First Officer since he had at least some information to fly with. I reverted my ADC information to his side as well. By the time we ended up being vectored onto the ILS; my information was back as well; with fairly good agreement between all three airspeed and altitude displays. We acquired the runway visually; in moderate rain; just outside the final approach fix. The First Officer's wiper wasn't working so we transferred controls back to me; and I landed normally. (Wiper was found to function normally after landing). Upon contacting Maintenance Control; the Maintenance Controller didn't seem surprised at this occurrence; saying in an offhand manner 'Ah; probably some moisture in the pitot/static lines.' I mention this not to disparage the Maintenance Controller (who was quite professional and helpful); but because it suggests to me that this happens with at least some regularity; and that's worrisome.Night IMC; thunderstorms in the area; we'd been flying in thick cirrus for a while which probably led to the (supposed) moisture in the static system; and; obviously; the mechanical abnormality of losing all airspeed and Mach information. The condition of being faced with flying a jet; at high altitudes; in night IMC; with no airspeed or Mach information. Secondly; because of aircraft behavior (buffeting and possible tuck); we suspect we exceeded the Mmo limitation. That was remedied immediately by slowing down.Why was this able to happen? Why were 3 separate static systems able to be simultaneously affected this way? And why did our Maintenance Controller not seem very surprised? If there is indeed a trend of moisture in the static systems affecting airspeed/altitude display; it would seem to me that finding a mechanical fix needs to be a priority. Perhaps consultation with Embraer would help?
EMB-145 flight crew experiences loss of pitot static instruments at FL350 during descent. With indicated airspeed decreasing; Mach buffet is encountered and correctly diagnosed by the Captain; who raises the nose to decrease airspeed.