B747 Undifferentiated or Other Model
Flight Crew Last 90 Days 200; Flight Crew Total 20000; Flight Crew Type 3500
Aircraft Equipment Problem Critical
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft
After takeoff gear selected up. Heard a bang; and then got EICAS messages gear disagree and gear door. We noticed nose gear was not indicating retracted. We ran 'gear disagree' checklist; per QRH. Ran 'gear door' checklist per QRH; up thru step 6. At step 4 when gear handle selected down heard a very loud bang. We stopped checklist there because we were afraid to raise gear as checklist directed; because of concern gear may not come back down. Also noticed vibration on number 2 engine of N1 2.5-4.5. Dumped fuel according to QRH; declared an emergency; and returned for landing. Landing uneventful.
After takeoff gear selected up. Heard a bang and got a gear disagree EICAS 'gear door' EICAS. We noticed that the gear was not retracted. We ran gear door and gear disagree checklist as per QRH up to step 6. At step 4 when gear handle selected down; heard a loud bang. We then decided not to raise the gear as per the checklist due to concerns about damage to the nose gear doors. Also noticed a higher than normal vibration on Engine #2. We then dumped fuel; declared an emergency; returned uneventfully.
B747 flight crew experiences a loud bang from the nose gear area when the landing gear is selected up. EICAS landing gear disagree and gear door disagree messages were displayed. When the gear is selected down in compliance with QRH procedures another loud bang is heard and vibration is noted on the number two engine. The crew elects to discontinue QRH procedures and return to the departure airport.