B737 Next Generation Undifferentiated
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 126; Flight Crew Total 107; Flight Crew Type 107
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Aircraft Equipment Problem Dissipated; Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft
On takeoff we noticed an unknown odor in the flight deck. The #1 engine had previously been changed. Flight Attendant A called and they also smelled the odor in the cabin. As we climbed out the odor seemed to be dissipate. We looked at the smoke/fire/fumes checklist and determined it was not applicable to our situation. The flight attendants said the odor seemed to have somewhat cleared up so we continued on to ZZZ. They said the odor came back on the descent into ZZZ so we wrote it up when we landed. We also did a logbook entry and maintenance had me fill out the paperwork for odor in the cabin.
After takeoff; there was a strong odor in the flight deck. After reaching a safe altitude; I called the Flight Attendants and asked them if they smelled anything. I also asked if there was anything burning in the ovens. Both forward and aft Flight Attendants smelled the odor and said there was nothing burning in the oven. The odor dissipated fairly quickly in the flight deck on climb out and the forward flight attendants also said they didn't smell the odor anymore. Aft flight attendants reported that the odor was still notable but felt like it was dissipating. The odor also returned on descent.We talked to Maintenance upon landing and filled out appropriate forms; also entered appropriate write up in the maintenance log.The aircraft had just come out of maintenance with a replaced number 1 engine. We were aware of this and assumed the odors were attributed to maintenance performed on new engine.
B737 flight crew reported a strong odor was noticed during initial climb which dissipated as the flight continued; but returned during descent for landing.