Narrative:

We arrived ZZZ about 20 min early. We had to wait for a gate. Ramp control assigned us to holding spot [a]. Aircraft Y (an A320) was ahead of us on the taxiway. Ramp assigned them to spot [B]. They arrived there first; and then we followed into holding spot a. There was also aircraft Z on spot [C].we were advised by [company] operations that we were waiting for a flight to depart [a gate]. We listened to ground control and heard [the flight] receive its pushback clearance. We advised ramp that our gate was opening. Ramp cleared us to taxi from holding spot a to spot D; and then to contact ground control.as I began to taxi from spot a; I noted that we were centered on our line (a) and that aircraft Y was centered on their line B. I began a slow taxi while looking out my side window at our left wing. After I thought that my left wing tip was clear of the airbus; I turned my head back forward to continue taxi. A few seconds later; I felt a moderate bump and the nose pulled to the left (I estimate about a 12-18 inches over a period of about 1 second?) I stopped the airplane; not immediately sure what had happened. (I wondered if we had perhaps rolled into a misplaced chock? With our left main tire.) it took a few seconds for my mind to process the fact that our wing tip had struck the airbus.we stopped the taxi; set the parking brake; and advised ramp that we thought we may have struck the wing of the adjacent airplane. We also advised [company] operations. After a few minutes; operations advised that airport ground safety teams would come out to inspect the airplanes. We made a PA announcement to the passengers advising that we may have struck the other airplane and that our taxi would be delayed pending analysis. We advised them that we might need to be towed to the gate or that we might need to deplane at this location and board busses to the terminal.numerous ground safety vehicles arrived on the scene. Many inspectors began taking photos of the wingtips and the position of the airplanes. (During this time; none of the inspectors were communicating with us via radio or intercom.) this went on for at least 45 minutes. We contacted [company] operations to determine how we would handle the passengers. Eventually; we learned that an air stair would be brought to the airplane and that passengers would be bussed to the terminal. We advised the passengers.after some time; an air stair was brought to the airplane. Initially; airport operations brought the air stair to door 2R. (There were numerous vehicles blocking access to door 1L.) since this was a 737-900; we (the pilots) realized that this presented a possible 'tail tip' risk as passengers moved aft to deplane. So we stopped the deplaning before it started. We talked to the ground safety people out the window to explain the tail tip risk. We got the airport operations people to reposition the air stair to door 1R for deplaning. The passengers deplaned and were taken to the terminal. Vehicles were arranged to take the flight attendants and pilots to their various operations. Discussion items/causes:1. Plot X holding points a and B. Aircraft sizes and limitations.while ground safety people were documenting the wingtip contact; I spoke through the flight deck window with several of the investigators. They advised me that both airplanes were; in fact; centered on their respective hold point lines. The ground safety investigators advised me further that; according to documents that they had; that 2 mainline narrow body airplanes were not supposed to be parked adjacent to one another at holding points a and B. They indicated that 2 mainline narrow body airplanes could be parked at adjacent to each other at B and C; but not at a and B.we were familiar with [company] page 10-7 that shows the location of plot X. That page has a note that limits aircraft size to 757-300 or smaller. There are no other notes on that page that show any other limitations. While waiting for the ground safety people to finish their analysis and documentation; we reviewed all [company] 10-7 pages and airport pages. We found no addition limitations on aircraft size or pairings related to holding spots a and B in our pilot operating charts.2. Wingtip clearance perception while on a published centerline.I had verified that both our airplane and aircraft Y were centered on their respective hold point centerlines before I began to taxi. This led me to expectation bias on the subsequent attempt to taxi out of the hold point. We taxi past other airplanes with minimal wingtip clearance routinely at ZZZ. When doing so; we routinely verify that both airplanes are centered on their respective taxi lines. When they are; we routinely pass 'close'; but reliably clear. Thus; we come to 'expect' that being on the centerline will result in a close; but clear; passing. In short; we trust where the lines are drawn. Therefore; when passing the other airplane; our thought process is more directed toward 'when' we are clear (and able to turn); less on 'if' we are clear. Both airplanes being on centerline brings the expectation that we will be laterally clear; watching the wingtips 'verifies' that the expected clearance occurs. Repeating this experience hundreds of times solidifies that expectation. Thus; in my mind; as I was looking at my wing tip; my thinking was more on 'when' our wingtip was past the airbus; and less on 'if' we would clear.so as I looked back toward my wing tip; I saw my winglet; from my vantage point; 'to the left of' (and therefore; likely longitudinally 'further aft than') the airbus winglet. As we proceeded forward; from my perspective; I saw what I thought was my winglet 'passing' the airbus winglet. My winglet was; from my perspective; now 'to the right of' (and; I thought; longitudinally 'forward of') the airbus. Since it was night; depth perception was reduced; and so I did not perceive that my wingtip was laterally 'inside of' the airbus wingtip. Nor did I have any expectation that this could be likely; given that we were both centered on our taxi lines.3. Communication with ground safety personnel during investigation and deplaning.I felt that we received inadequate communication from ground safety investigators during their investigation and documentation process. There was no dedicated 'communicator' to speak with us on the flight deck. No one hooked up to the intercom to keep posted on what was going on. As a result; I felt like I didn't know what was going on; and I was not able to communicate as much information to our passengers as I would have liked.once the airport operations people began preparing for passenger deplaning; 2 safety threats occurred. First; poor coordination with the airport operations personnel produced a threat of an inadvertent slide deployment. They decided to bring an air stair to door 2R instead of door 1L. We had previously advised the flight attendants that an air stair would be coming to the airplane within a few minutes. But we did not see the air stair approaching door 2R from the flight deck. So we didn't know the air stair was approaching. The main cabin doors were still armed at this point. The aft flight attendants saw the air stair approaching and advised both us and the purser; fortunately; we got the doors disarmed before the air stair arrived at door 2R.second; as discussed above; deplaning from 2R instead of a forward door involved the risk of a tail tip. We were not consulted about a plan as to which door would be used for deplaning; so we had to scramble to stop the deplaning from door 2R and redirect it to door 1R.my main point in this section is to say that the communication and coordination with the ground safety and airport operations people could be much improved by having a dedicated ground-to-airplane 'communicator' to coordinate with the crew on all these issues.4. Increased operations at ZZZ during summer monthsfrom my perspective; ZZZ has seen greatly increased operations this summer. This has resulted in much higher utilization of [company] gates. This; in turn; results in higher utilization of the various holding points around the airport as aircraft wait for a gate. I believe that this may have been creating difficulty for [company] ramp and operations in finding any place to park airplanes in the moments prior to our event. This may have led to errors in assigning which airplanes can appropriately park at holding spots a and B.5. Duty day and fatiguethis was a 1 day turn with a deadhead segment to ZZZ1; followed by an operating segment from ZZZ1 to ZZZ. Although the duty day was somewhat long; I do not feel that fatigue was an issue for me in this incident.6. Inadvertent ipad lock function riskwhile approaching plot X after landing; I attempted to open my ipad to ZZZ 10-7. I was unable to do so as the 'device locked' icon appeared. I did not initially know why it appeared. Since I was unable to pull up the desire page; I asked the first officer to expand the view of plot X on his ipad; which he did. I referenced the location of spot a by looking cross-cockpit on the first officer's ipad.once parked at spot a; I noted that the 'locked' icon in the upper right corner of my ipad showed yellow and locked. I think this may have occurred during approach; I had swiped down from the battery icon to reduce the brightness of my display. I am guessing that I may have bumped the 'lock' icon and inadvertently locked my ipad.I bring this up to highlight a potential risk to ground operations only. I do not feel that this had any effect on our events that evening; I am very familiar with plot X and was able to reference the first officer's ipad while approaching a. While parked at a; and before our event; I had unlocked my ipad and had page 10-7 displayed.7. Wing illumination lighti did not use the wing illumination light to light up my wing tip during the event. It occurred to me after the event that this might have been helpful with depth perception. But I do not see that as a procedure in the flight manual or fom; and I do not recall ever being taught that as a technique for taxiing with close wingtip clearance.8. Debriefingsthe first officer and I did some debriefing of our event in the flight deck while the ground safety investigation/documentation process was underway. More debriefing occurred in the flight office with the help of alpa personnel. We also met the crew of the A320 in the flight office and debriefed with them as well. I felt all of these debriefings were adequate.I feel that we did not debrief as well as I would have liked with the flight attendants. By the time the passengers had left; there was considerable pressure for all crew to get off the airplane so that maintenance could tow it. So we didn't get much of a chance to debrief with them. In retrospect; I feel that I should have carved out more time after passenger deplaning to debrief with the flight attendants.summary/recommendations:1. Ground safety personnel told us that according to their documents; a 737 and an A320 are not supposed to be parked side-by-side at holding points a and B. But we have no such information on our pilot operating charts.2. A combination of expectation bias and reduced depth perception at night caused me to fail to recognize that my wingtip was inside the A320 wingtip.3. I would recommend that anytime airport operations or ground safety personnel are handling a situation like ours; that a dedicated 'ground-to-airplane' communicator be assigned to improve coordination.

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Original NASA ASRS Text

Title: B737 flight crew reported making contact with an A320 wingtip while attempting to taxi from a holding point.

Narrative: We arrived ZZZ about 20 min early. We had to wait for a gate. Ramp control assigned us to holding spot [A]. Aircraft Y (an A320) was ahead of us on the taxiway. Ramp assigned them to spot [B]. They arrived there first; and then we followed into holding spot A. There was also Aircraft Z on spot [C].We were advised by [company] operations that we were waiting for a flight to depart [a gate]. We listened to ground control and heard [the flight] receive its pushback clearance. We advised ramp that our gate was opening. Ramp cleared us to taxi from holding spot A to spot D; and then to contact ground control.As I began to taxi from spot A; I noted that we were centered on our line (A) and that Aircraft Y was centered on their line B. I began a slow taxi while looking out my side window at our left wing. After I thought that my left wing tip was clear of the Airbus; I turned my head back forward to continue taxi. A few seconds later; I felt a moderate bump and the nose pulled to the left (I estimate about a 12-18 inches over a period of about 1 second?) I stopped the airplane; not immediately sure what had happened. (I wondered if we had perhaps rolled into a misplaced chock? with our left main tire.) It took a few seconds for my mind to process the fact that our wing tip had struck the Airbus.We stopped the taxi; set the parking brake; and advised ramp that we thought we may have struck the wing of the adjacent airplane. We also advised [company] operations. After a few minutes; operations advised that airport Ground Safety teams would come out to inspect the airplanes. We made a PA announcement to the passengers advising that we may have struck the other airplane and that our taxi would be delayed pending analysis. We advised them that we might need to be towed to the gate or that we might need to deplane at this location and board busses to the terminal.Numerous ground safety vehicles arrived on the scene. Many inspectors began taking photos of the wingtips and the position of the airplanes. (During this time; none of the inspectors were communicating with us via radio or intercom.) This went on for at least 45 minutes. We contacted [company] operations to determine how we would handle the passengers. Eventually; we learned that an air stair would be brought to the airplane and that passengers would be bussed to the terminal. We advised the passengers.After some time; an air stair was brought to the airplane. Initially; airport operations brought the air stair to door 2R. (There were numerous vehicles blocking access to door 1L.) Since this was a 737-900; we (the pilots) realized that this presented a possible 'tail tip' risk as passengers moved aft to deplane. So we stopped the deplaning before it started. We talked to the ground safety people out the window to explain the tail tip risk. We got the airport operations people to reposition the air stair to door 1R for deplaning. The passengers deplaned and were taken to the terminal. Vehicles were arranged to take the flight attendants and pilots to their various operations. Discussion items/Causes:1. Plot X holding points A and B. Aircraft sizes and limitations.While ground safety people were documenting the wingtip contact; I spoke through the flight deck window with several of the investigators. They advised me that both airplanes were; in fact; centered on their respective hold point lines. The Ground Safety investigators advised me further that; according to documents that they had; that 2 mainline narrow body airplanes were not supposed to be parked adjacent to one another at holding points A and B. They indicated that 2 mainline narrow body airplanes could be parked at adjacent to each other at B and C; but not at A and B.We were familiar with [company] page 10-7 that shows the location of Plot X. That page has a Note that limits aircraft size to 757-300 or smaller. There are no other notes on that page that show any other limitations. While waiting for the ground safety people to finish their analysis and documentation; we reviewed all [company] 10-7 pages and airport pages. We found no addition limitations on aircraft size or pairings related to holding spots A and B in our pilot operating charts.2. Wingtip clearance perception while on a published centerline.I had verified that both our airplane and Aircraft Y were centered on their respective hold point centerlines before I began to taxi. This led me to expectation bias on the subsequent attempt to taxi out of the hold point. We taxi past other airplanes with minimal wingtip clearance routinely at ZZZ. When doing so; we routinely verify that both airplanes are centered on their respective taxi lines. When they are; we routinely pass 'close'; but reliably clear. Thus; we come to 'expect' that being on the centerline will result in a close; but clear; passing. In short; we trust where the lines are drawn. Therefore; when passing the other airplane; our thought process is more directed toward 'when' we are clear (and able to turn); less on 'if' we are clear. Both airplanes being on centerline brings the expectation that we will be laterally clear; watching the wingtips 'verifies' that the expected clearance occurs. Repeating this experience hundreds of times solidifies that expectation. Thus; in my mind; as I was looking at my wing tip; my thinking was more on 'when' our wingtip was past the Airbus; and less on 'if' we would clear.So as I looked back toward my wing tip; I saw my winglet; from my vantage point; 'to the left of' (and therefore; likely longitudinally 'further aft than') the Airbus winglet. As we proceeded forward; from my perspective; I saw what I thought was my winglet 'passing' the Airbus winglet. My winglet was; from my perspective; now 'to the right of' (and; I thought; longitudinally 'forward of') the Airbus. Since it was night; depth perception was reduced; and so I did not perceive that my wingtip was laterally 'inside of' the Airbus wingtip. Nor did I have any expectation that this could be likely; given that we were both centered on our taxi lines.3. Communication with Ground Safety personnel during investigation and deplaning.I felt that we received inadequate communication from Ground Safety investigators during their investigation and documentation process. There was no dedicated 'communicator' to speak with us on the flight deck. No one hooked up to the intercom to keep posted on what was going on. As a result; I felt like I didn't know what was going on; and I was not able to communicate as much information to our passengers as I would have liked.Once the airport operations people began preparing for passenger deplaning; 2 safety threats occurred. First; poor coordination with the airport operations personnel produced a threat of an inadvertent slide deployment. They decided to bring an air stair to door 2R instead of door 1L. We had previously advised the flight attendants that an air stair would be coming to the airplane within a few minutes. But we did not see the air stair approaching door 2R from the flight deck. So we didn't know the air stair was approaching. The main cabin doors were still armed at this point. The aft flight attendants saw the air stair approaching and advised both us and the purser; fortunately; we got the doors disarmed before the air stair arrived at door 2R.Second; as discussed above; deplaning from 2R instead of a forward door involved the risk of a tail tip. We were not consulted about a plan as to which door would be used for deplaning; so we had to scramble to stop the deplaning from door 2R and redirect it to door 1R.My main point in this section is to say that the communication and coordination with the ground safety and airport operations people could be much improved by having a dedicated ground-to-airplane 'communicator' to coordinate with the crew on all these issues.4. Increased operations at ZZZ during summer monthsFrom my perspective; ZZZ has seen greatly increased operations this summer. This has resulted in much higher utilization of [company] gates. This; in turn; results in higher utilization of the various holding points around the airport as aircraft wait for a gate. I believe that this may have been creating difficulty for [company] Ramp and Operations in finding any place to park airplanes in the moments prior to our event. This may have led to errors in assigning which airplanes can appropriately park at holding spots A and B.5. Duty day and FatigueThis was a 1 day turn with a Deadhead segment to ZZZ1; followed by an operating segment from ZZZ1 to ZZZ. Although the duty day was somewhat long; I do not feel that fatigue was an issue for me in this incident.6. Inadvertent IPAD Lock Function riskWhile approaching Plot X after landing; I attempted to open my IPAD to ZZZ 10-7. I was unable to do so as the 'DEVICE LOCKED' icon appeared. I did not initially know why it appeared. Since I was unable to pull up the desire page; I asked the first officer to expand the view of Plot X on his IPAD; which he did. I referenced the location of spot A by looking cross-cockpit on the first officer's IPAD.Once parked at spot A; I noted that the 'locked' icon in the upper right corner of my IPAD showed yellow and locked. I think this may have occurred during approach; I had swiped down from the Battery icon to reduce the brightness of my display. I am guessing that I may have bumped the 'LOCK' icon and inadvertently locked my IPAD.I bring this up to highlight a potential risk to ground operations only. I do not feel that this had any effect on our events that evening; I am very familiar with Plot X and was able to reference the First Officer's IPAD while approaching A. While parked at A; and before our event; I had unlocked my IPAD and had page 10-7 displayed.7. Wing Illumination LightI did not use the wing illumination light to light up my wing tip during the event. It occurred to me after the event that this might have been helpful with depth perception. But I do not see that as a procedure in the Flight Manual or FOM; and I do not recall ever being taught that as a technique for taxiing with close wingtip clearance.8. DebriefingsThe First Officer and I did some debriefing of our event in the flight deck while the ground safety investigation/documentation process was underway. More debriefing occurred in the flight office with the help of ALPA personnel. We also met the crew of the A320 in the flight office and debriefed with them as well. I felt all of these debriefings were adequate.I feel that we did not debrief as well as I would have liked with the flight attendants. By the time the passengers had left; there was considerable pressure for all crew to get off the airplane so that maintenance could tow it. So we didn't get much of a chance to debrief with them. In retrospect; I feel that I should have carved out more time after passenger deplaning to debrief with the flight attendants.Summary/Recommendations:1. Ground Safety Personnel told us that according to their documents; a 737 and an A320 are not supposed to be parked side-by-side at holding points A and B. But we have no such information on our pilot operating charts.2. A combination of expectation bias and reduced depth perception at night caused me to fail to recognize that my wingtip was inside the A320 wingtip.3. I would recommend that anytime airport operations or Ground Safety personnel are handling a situation like ours; that a dedicated 'ground-to-airplane' communicator be assigned to improve coordination.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.