B737-800 first officer reported using the wrong gate number when calling ground control for pushback...

Narrative:

In preparation for pushback; the left engine was started at the gate due to a deferred APU. The captain instructed me to call ground control to advise of the engine start. When I made the transmission; I incorrectly stated the gate number. Both gates are at the corner of the building and I didn't realize I was looking at the wrong point on the company terminal page in the jepp charts. After the engine start; the captain instructed that the number 2 engine would be started using the crossbleed procedure after pushback. My next transmission to ground for push clearance again stated the wrong gate number. As the aircraft began to move under tow; another aircraft from another ramp had to stop to avoid a conflict. The time of day was early morning twilight and the conflict aircraft flashed his lights to the tug crew to advise the problem. Ground control then advised the other aircraft if he had room to maneuver around our aircraft. At this point; I could see the gate number from the jet bridge since the aircraft was far away enough from the gate to see the sign from the flight deck. Stating the wrong gate was my fault but no one caught the mistake until a conflict was about to take place.the threats I observed mostly consist of me being a new pilot to the company and aircraft. This was my second time starting an engine using external power while on the line; so I was distracted by the additional checklist. If there was a sign or marking on the ground visible from the flight deck to identify the gate position while parked at the gate; it could have mitigated the error.

Original NASA ASRS Text

Title: B737-800 First Officer reported using the wrong gate number when calling Ground Control for pushback which resulted in a conflict with an outbound aircraft. The actual gate number could not be seen from the cockpit and had to be determined from the parking diagram (incorrectly).

Narrative: In preparation for pushback; the left engine was started at the gate due to a deferred APU. The Captain instructed me to call ground control to advise of the engine start. When I made the transmission; I incorrectly stated the gate number. Both gates are at the corner of the building and I didn't realize I was looking at the wrong point on the company terminal page in the Jepp charts. After the engine start; the Captain instructed that the number 2 engine would be started using the crossbleed procedure after pushback. My next transmission to ground for push clearance again stated the wrong gate number. As the aircraft began to move under tow; another aircraft from another ramp had to stop to avoid a conflict. The time of day was early morning twilight and the conflict aircraft flashed his lights to the tug crew to advise the problem. Ground control then advised the other aircraft if he had room to maneuver around our aircraft. At this point; I could see the gate number from the jet bridge since the aircraft was far away enough from the gate to see the sign from the flight deck. Stating the wrong gate was my fault but no one caught the mistake until a conflict was about to take place.The threats I observed mostly consist of me being a new pilot to the company and aircraft. This was my second time starting an engine using external power while on the line; so I was distracted by the additional checklist. If there was a sign or marking on the ground visible from the flight deck to identify the gate position while parked at the gate; it could have mitigated the error.

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.

Attributes
ACN	1392132
Time
Date	201610
Local Time Of Day	0601-1200
Place
Locale Reference	TPA.Airport
State Reference	FL
Environment
Light	Daylight
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Total 14300
Events
Anomaly	Conflict Ground Conflict Critical Deviation - Procedural Published Material / Policy Ground Incursion Taxiway

B737-800 first officer reported using the wrong gate number when calling ground control for pushback which resulted in a conflict with an outbound aircraft. The actual gate number could not be seen from the cockpit and had to be determined from the parking diagram (incorrectly).