Date: 201207
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Airspace: Class C ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Commercial
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Critical
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Aircraft Aircraft Damaged; Flight Crew Diverted; Flight Crew Landed As Precaution; General Declared Emergency; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: We reported to the gate as required to begin the day on our show time.  It was a first flight of the day; so I had to do the required inspection during the pre-flight including all the panels that needed to be opened.  I did not find any discrepancy on the airplane except for the MEL'd items on the release.  Everything was proceeding as a normal operation day.  About 5 minutes prior to our push back; we heard a report from the tower about micro bursts on the departure end of our departing runway.  We then taxied to the runway and upon reaching the hold short line; the CA (flying pilot) briefed about a potential abort or a go around action if we received any wind shear warnings on takeoff roll or after rotation.  On our taxi Tower was asked by a different aircraft about the reports; the Tower had reported that he was not getting any more warnings and the microburst seemed to have dissipated.  After the brief; we decided that it was safe to proceed on our flight.  On the TO roll; everything was normal up until 150-250 feet AGL after rotation.  I saw the PLI come down all the way to the top of the Flight Director but the Low Speed awareness tape was not visible; a split second after the Shaker and the Pusher activated prompting the CA to react by executing a stall recovery; the CA advanced the thrust levers full forward and pushing on the control column forward.  We both thought that what was happening was due to Windshear; even though we didn't have any windshear warning.   Looking at my PFD I had noticed that the airspeed is still continuing to increase and our VSI was indicating a climb of 1300 to 1800 FPM.  I was continuing to scan what was happening inside the airplane; outside the airplane (making sure we are not going to hit any terrain or structures in the vicinity); and providing some information to ATC as needed.  Upon reaching what we thought as a safe altitude and airspeed; I continued to do the after take off flow.  Throughout this period; the shaker and pusher were still active and warning bells are sounding.  ATC was informed of the event that was happening and we told them that we were having an issue with the airplane.  After leveling off at 6000 feet MSL the CA transferred the control over to me and I proceeded to fly the airplane.  It is worth mentioning that we had a jump seater on board from another airline and he was helpful in troubleshooting the problem.  The Captain proceeded to do the SPS ADVANCED QRH procedure followed by INADVERTENT STALL PROTECTION ACTIVATION procedure in which after it was finished; the Shaker; Pusher and Bells turned off.  After that seems to have solved the problem; we discussed our options on which airport to go to because we had decided that it was not longer safe to continue on to destination.  After some considerations; we thought ZZZ would be the best place to divert; for safety; long runways; emergency response capabilities; and maintenance availability.  We definitely did not want to go back to the departure airport due to the previous weather report.  Also being a mainline base; it turned out to be a better choice to re-accommodate the passengers.  On the way to ZZZ; the Captain had declared and emergency situation due to the fact that we were going to be overweight.  He asked if I was comfortable doing the landing; since his PFD seemed to be unreliable.  I said yes; the airplane seems to be flying normally.  The landing at ZZZ seemed to be uneventful; more like a normal landing.  We were met by the Emergency response crews and they did an inspection before we proceeded to taxi to the gate.  Upon parking and de-boarding; we were met by maintenance crew and they had discovered that the AOA indicator on the Captain's side was bent; which was not the case when I did my pre-flight walk around.  The  weather threat that was reported; was what we thought was the main culprit in what was going on in the aircraft initially.  We weren't able to get our minds into thinking the other signs by comparing the different information on our PFD's that this was an actual equipment malfunction and not weather related.  We both could have been more assertive in figuring out that the problem was an equipment malfunction instead of weather related by comparing the conflicting information that we are receiving on our PFD's.  I believe that our actions were done to the best of our abilities given the critical phase of flight.


Second narrative: Take-off was normal until just after rotation (approx. 150-200AGL) my PLI [Pitch Limit Indicator] came down; and the Shaker activated immediately.  My initial reaction was MAX thrust and to fly the Shaker; and increase both Airspeed and gain Altitude.  Initially; we both thought we were encountering windshear; although we had NO windshear indication/warning.  Upon reaching a safe altitude/aircraft configuration; we advised ATC we had a maintenance problem (shaker was going off in background); and needed delay vectors.  I gave control of the aircraft to the First Officer and ran the QRH for EICAS message 'SPS Advanced'; as well as the 'Inadvertent Stall Protection Activation.  I will add; we had a Jump seater in the jumpseat; who was very helpful in determining what we were dealing with.  I briefed the Flight Attendant on what was going on; and would get back to her shortly.  After discussing our options with the First Officer; we decided our safest course of action was to divert.  I updated Dispatch with our problem and intentions.  While Dispatch suggested ZZZ1; the First Officer and myself decided that ZZZ offered the safest outcome.  I declared an emergency; and used Captain's authority to proceed to ZZZ.  I advised Dispatch of our plan.  Safety; weather; fuel; landing weight; airport facilities; Long Runways; maintenance and overall services made ZZZ the safest decision for a diversion airport. (We decided an air return was not the best option due to the earlier report of W/S and Micro burst reports in the vicinity) I then made a PA to the passengers informing them of a 'maintenance issue;' and that we would be diverting to ZZZ; and be on the ground in 20 minutes.  We landed overweight without incident in ZZZ. The First Officer was PF the second part of the flight; as my (CA) instruments were unreliable.  The First Officer did an excellent job and landed very smoothly.  Although we didn't request any assistance upon landing; the Fire Department followed their SOP and checked the exterior of the Aircraft.  Upon our and MX post-flight inspection; the AOA on my (Captain's) side was broken and bent.  My First Officer assured me that on his pre-flight inspection; the (Captain's) AOA was normal/undamaged. This was a circumstance I have never seen before on-line or in the simulator.  I believe the pilot group would benefit from this type of situation/ training in the simulator.


Synopsis: EMB145 Flight Crew taking off with micro bursts in the area experiences a stall warning with stick shaker activation shortly after takeoff.  The Capitan responds with maximum power and lowers the nose but the warnings continue as airspeed increases.  After running the QRH procedure for Inadvertent Stall Protection Activation; the warnings cease and the crew elects to divert to a suitable airport for an uneventful landing.  Maintenance discovers that the Captain's angle of attack vane is bent.