Date: 201711
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: Marginal
Light: Daylight
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ramp ZZZ
Aircraft component: Nosewheel Steering
Component problem: Failed; Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Training / Qualification; Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Aircraft Aircraft Damaged; General Maintenance Action
Contributing factors: Manuals; Procedure; Aircraft; Human Factors
Primary problem: Ambiguous

Narrative: Few minutes before the scheduled departure time we contacted the Ramp Control for pushback instructions and we were told to push back. The ground crew complied with the instructions and pushed the airplane back. The ground crew disconnected the aircraft. Engine 1 and the APU were running; Engine 2 was off. The hydraulic pump switches were all in the 12 o'clock position. After the ground equipment was removed and clear of the aircraft the Ramp Controller instructed us to taxi straight ahead and make a right turn to and to monitor the next controller. I applied power to Engine 1; quickly followed by pressing down on the tiller; but I immediately felt that I did not have steering control and as the airplane gained momentum it started to turn right due to pure asymmetrical thrust. This is the second time that I experienced a steering failure on initial taxi out. I noticed the STEER OFF message on the EICAS even though I was firmly attempting to engage the steering. I reduced thrust to idle and brought the airplane to a stop. I switched the electric hydraulic pumps 1 and 2 to ON (even though Engine 1 was running) and tried to engage the steering one more time. This time I got an advisory (blue) STEER FAIL message on the EICAS. I reconfigured the hydraulic pumps to their normal position (AUTO). I also recycled the parking brake; and tried to engage the steering again; unsuccessfully.At this point the airplane was facing due west and blocking about half of the entrance of the [taxiway]. The Ramp Controller was also questioning our actions; which did not match his instructions. The First Officer explained that we had a steering failure and that we probably needed to go back to the gate. The First Officer and I discussed that it was going to be very challenging to taxi without steering. So I told the Ramp Controller that I was not sure if a return to gate was necessary and that I could just taxi the airplane back to get it out of the way and call maintenance. I then applied power to Engine 2 and carefully proceeded to make a right turn back into the ramp using differential braking. In doing so I felt unusual resistance and difficulty trying to make the airplane go straight. Ramp personnel and [Company] Line Maintenance in the area quickly approached the AC (without anybody calling them) and instructed us to stop immediately (we were already stopped). A [Company] Mechanic plugged his head set and told us that the nose wheel had flipped 180 degrees (we had a LG NO DISPATCH message on the EICAS). After several attempts the ground personnel and maintenance managed to turn the nose wheel to the right position and towed the airplane back to the gate. During this time I contacted the dispatcher and explained the situation. Once at the gate I logged the maintenance discrepancies; and contacted MX Control. We then swapped aircraft and completed the flight with no issues.My perception of Steering Failures on initial taxi out:As I mentioned; this is the second time that this happens to me. I always thought this issue was mainly caused by the ground personnel leaving the Steering Switch accidentally in the DISENG position. It is important to note that the first time I had this issue the External Power Connection Access Panel was on MEL; and taped over; so the crew could not verify the position of the switch. During that occasion Maintenance personnel approached the aircraft on the ramp and had us go through a 'button pushing' sequence to reset the system. I was under the impression that they also checked the exterior panel; but I never actually learned what they did and what the root of the problem was. Today; I assumed it was also the outside switch that had been left in the DISENG position.Why I decided to steer the airplane using differential braking:I had a STEER FAIL in flight while on approach to ZZZ on Oct 2017. After landing on Runway XX I steered the airplane onto a high-speed taxiway; stopped and asked for the QRH. The QRH states that the procedure for a steer failure is to steer he airplane using differential braking and rudder. Nothing more. So; I did just that and I was able to taxi the airplane all the way to the gate using this method. Also; during my upgrade PC I was given a steer failure during taxi out and was told to demonstrate taxiing with differential braking and rudder. Therefore; when the steer failed on taxi out on Nov 2017 I felt fully capable of safely steering the airplane back to the ramp area; and away from an active taxiway using differential braking.What I have realized:On Nov 2017 I was single engine. While common sense says that it is not a good idea to try to steer using differential braking while on single engine I have never been explicitly instructed not to do so; or that the airplane is not able to withstand it. Doing some reading on the subject I found that the Systems Manual has a note stating that 'after a power up; the first steering engagement must be performed with the airplane stopped. If this condition is not met; the hard over test might not be successfully accomplished by the system and STEER FAIL message might be displayed.'I have developed the habit of sometimes letting the airplane advance before engaging the steering. I cannot remember when exactly I started doing this; but I believe I might have done it a few times during CA IOE. I don't remember explicitly being told not to do that. But with this new knowledge I suspect that my two steering failures on initial taxi out might have been caused by me not knowing how to use the system properly. The company should emphasize to new Captains during training the operation; limitations; and different modes of the E-JET steering system. I remember only briefly going over the system during initial training. During upgrade no particular emphasis was placed on this system. [The Company] cannot take it for granted that all First Officers have a solid understanding of a system that they don't have operational experience in. [The Company] should divulge information stating that the E-JET steering system must be engaged before the airplane moves; and that single engine 'Free Wheel Steering' is not allowed.




Synopsis: EMB-175 Captain reported that they were unable to taxi due to loss of steering.