A300 flight crew reported gear did not retract after takeoff.

Attributes
ACN	1764551
Time
Date	202010
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	A300
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Hydraulic Main System
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Maintenance Deviation - Procedural Published Material / Policy

Narrative:

On take-off runway xx; received flashing green hydraulic pump low pressure. Landing gear would not retract. The ECAM was indicating that the green pumps failed. Leveled at 2000 ft. [Requested priority handling] with ZZZ departure. After 2-3 minutes; the hydraulic issue stopped. Pumps back to normal. Raised landing gear. No other issues noted. I continued to ZZZ1 for priority handling. No issues with configuring for landing.aircraft was released from contract heavy maintenance for a right main landing gear change. Maintenance suspects air in green hydraulic system.possible issue with heavy maintenance at ZZZ.

Original NASA ASRS Text

Title: A300 flight crew reported gear did not retract after takeoff.

Narrative: On take-off runway XX; received flashing green hydraulic pump low pressure. Landing gear would not retract. The ECAM was indicating that the green pumps failed. Leveled at 2000 ft. [Requested priority handling] with ZZZ departure. After 2-3 minutes; the hydraulic issue stopped. Pumps back to normal. Raised landing gear. No other issues noted. I continued to ZZZ1 for priority handling. No issues with configuring for landing.Aircraft was released from contract heavy maintenance for a right main landing gear change. Maintenance suspects air in green hydraulic system.Possible issue with heavy maintenance at ZZZ.

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.