B777 first officer reported that during climb; a loud sound was heard from the rear of aircraft; fol...

Narrative:

Prior to departure; aircraft was given MEL 21 for ram air inlet systems (left). After departure; climbing through approximately 15;000 feet; and assigned normal speed; we began to accelerate. As we accelerated through approximately 280 knots; a loud sound was heard from rear of aircraft; an aircraft shudder occurred momentarily and then an aircraft vibration persisted for the remainder of our flight.the flight attendants immediately started calling from multiple stations. They advised us passengers in the middle of the aircraft were experiencing loud noises and vibrations from outside the airplane and that the passengers were scared. We performed a quick analysis and confirmed we were pressurized; engines were running normally with no vibs and no EICAS messages. The captain transferred aircraft controls to me and discussed the situation further with the flight attendants. The captain and I evaluated and agreed the source of trouble was unknown; there was no associated non-normal checklist to address; but that continuing the flight was also not safe due to the aircraft vibrations we were experiencing through the flight controls.I flew the airplane; sent a divert message to company; and talked to ATC while the captain further coordinated with the company; flight attendants and passengers for landing. A collective decision was made to land overweight as to not delay our safe return and to taxi to the gate. We did prep the cabin for evacuation but briefed a normal landing was expected. Emergency equipment met us after landing and followed us to the gate. Maintenance said some large sections of air plumbing in belly of airplane; fed by the ram air inlet; had exploded into pieces.

Original NASA ASRS Text

Title: B777 First Officer reported that during climb; a loud sound was heard from the rear of aircraft; followed by a momentary shudder; then a vibration that persisted for the remainder of the flight.

Narrative: Prior to departure; aircraft was given MEL 21 for RAM AIR INLET SYSTEMS (LEFT). After departure; climbing through approximately 15;000 feet; and assigned normal speed; we began to accelerate. As we accelerated through approximately 280 knots; a loud sound was heard from rear of aircraft; an aircraft shudder occurred momentarily and then an aircraft vibration persisted for the remainder of our flight.The flight attendants immediately started calling from multiple stations. They advised us passengers in the middle of the aircraft were experiencing loud noises and vibrations from outside the airplane and that the passengers were scared. We performed a quick analysis and confirmed we were pressurized; engines were running normally with no VIBS and no EICAS messages. The Captain transferred aircraft controls to me and discussed the situation further with the Flight Attendants. The Captain and I evaluated and agreed the source of trouble was unknown; there was no associated non-normal checklist to address; but that continuing the flight was also not safe due to the aircraft vibrations we were experiencing through the flight controls.I flew the airplane; sent a divert message to company; and talked to ATC while the Captain further coordinated with the Company; Flight Attendants and passengers for landing. A collective decision was made to land overweight as to not delay our safe return and to taxi to the gate. We did prep the cabin for evacuation but briefed a normal landing was expected. Emergency equipment met us after landing and followed us to the gate. Maintenance said some large sections of air plumbing in belly of airplane; fed by the Ram Air Inlet; had exploded into pieces.

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	1544227
Time
Date	201805
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Pneumatic Ducting
Person 1
Function	Pilot Not 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 Published Material / Policy Deviation - Procedural Weight And Balance

B777 first officer reported that during climb; a loud sound was heard from the rear of aircraft; followed by a momentary shudder; then a vibration that persisted for the remainder of the flight.