Date: 201509
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Dusk
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ramp ZZZ
Second aircraft: Large Transport
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Human-Machine Interface; Distraction; Confusion; Communication Breakdown; Situational Awareness
Second reporter function: First Officer; Pilot Flying
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Aircraft
Detector: Person Flight Crew; Person Ground Personnel
When detected: Taxi
Result: Aircraft Aircraft Damaged
Contributing factors: Company Policy; Procedure; Human Factors
Primary problem: Procedure

Narrative: While parking at gate XX; the automated parking guidance and the marshaller parking guidance (should not have had both; should be one or the other) were not in agreement. Indeed; auto-guidance and marshaller guidance were one-eighty out. Furthermore; marshaller guidance was entirely non-standard signals. Indeed; none of the marshaller's signals were standard. Both First Officer and I noted the guidance (auto versus human) discrepancy; and the lack of signal standardization. Situation did not inspire confidence. Prudence dictated 'stop the jet'. We stopped the jet; set parking brake; and contacted Ramp. We advised Ramp that marshaller guidance and auto guidance were not in agreement. Ramp directed us to shutdown engines and await tow-in. We did so. Shortly thereafter; another aircraft impacted our right horizontal stabilizer with its left winglet. We briefed Flight Attendants and made calming PAs to passengers. We assisted Maintenance; over interphone; in separating the two aircraft; by restoring hydraulic pressure; applying full nose-up trim; and applying full aft yoke. As a post-script; when checking in on Crew Communication System (CCS) this/following morning; I received a CCS message to contact Ops. I did so. The person identified himself as a 'maintenance liaison' in Ops. He advised me that in the last week; three maintenance tow-ins had reported erroneous auto-guidance at Gate XX. He stated he had reported the erroneous Gate XX auto-guidance up-channel.


Second narrative: I was the FO. This trip was in conjunction with my continuing 756 IOE. The trip was completely uneventful until parking at gate XX. The weather was clear VFR upon arrival and our gate was immediately available. The Line Check Airman (LCA) conducted normal taxi procedure to the gate until turning into gate XX. There was a Marshaller at the gate that was giving conflicting information from the JBI-1900 Accu Park system. We were following the guidance of the system; however the Marshaller was giving conflicting direction by moving his right arm up and down as if to be trying to marshal us left. There was confusion and both the LCA and myself agreed we needed to stop the aircraft for clarification before moving further forward. We stopped about 40-50 feet short of the 757 parking spot and I contact Ramp control immediately to explain the situation in detail; and that we were holding position until we could get tugged into parking. Ramp control concurred and directed us to shut down and await a tug. We secured both engines and set parking break. The LCA explained the situation to the passengers and we awaited a tug. Approximately 5-7 minutes passed giving us enough time to actually debrief the entire arrival and landing; when all of a sudden there was a large strike felt to the aircraft. Ground personnel hooked up and told us that the aircraft at the gate behind us was just pushed back into our aircraft and that they were stuck together. We discussed the need to possibly secure the APU but it was determined by ground personnel that the exhaust was not an immediate concern. We were instructed to hold full nose up trim and horizontal stab up to aid in getting the jets separated. We assessed the damage during post flight and saw that the jet struck the right horizontal stab; damaging the tip of our stab and shearing off the other aircraft's winglet; and also continuing to scrape the bottom of the stab for about 20-25 feet. We were also informed that it was believed that the jet didn't have appropriate wing walkers and that the gate XX JBI-1900 had been written up three previous times with no corrective action. While we did stop short of the gate due to uncertainty of the marshaling; in accordance with expected actions based on previous formal guidance on such systems; I don't feel that any of our actions as the cockpit crew resulted in collision. Ramp control cleared the jet to push and was fully aware of our situation.


Synopsis: A B757 stopped short of the gate during taxi in because the autoparking and Marshaller gave conflicting directions. While waiting for a tow in; a another aircraft's ground crew pushed their aircraft to where it's winglet struck the B757's horizontal stabilizer.