Narrative:

Planned visual approach. VMC weather; winds 220 13g21. Positive stopping margins for all braking levels for both runways xxr and xxl. While turning final from a left base; tower asked if we would like to switch to runway xxl. We said yes and were cleared to land from more than 5 miles from the runway. Captain was pilot flying. Flew an uneventful visual approach to runway xxl with the exception of some unexpected turbulence/airspeed fluctuation at approximately 300 ft AGL. Pilot flying applied appropriate correction. Just prior to touchdown; pilot flying applied appropriate crosswind correction and aircraft landed on centerline within the first 1000 ft of the touchdown zone. Immediate severe shaking/oscillations of entire airframe occurred at touchdown. Directional control did not seem to be an issue. The shaking was easily the most violent I have ever felt in an airplane and would have equated to severe turbulence had we been airborne. Captain and I verbalized something to the effect of; 'I think we blew a tire.' I was not able to understand ATC transmissions while the plane was shaking -- too much ambient noise. Vibrations increased in intensity until aircraft had slowed to a near complete stop. Captain maintained runway centerline and was able to stop the aircraft in what seemed a typical distance. The captain was able to turn the aircraft to the left onto runway xy; stopping near the intersection with taxiway. Assuming that a tire had blown; captain instructed me to tell the flight attendants to remain seated. We initially declined tower's request to roll the fire trucks because we were under the assumption that we were simply dealing with a blown tire. Very shortly thereafter; the captain reconsidered and we asked tower to roll the fire trucks. Trucks took several minutes to arrive; and after some trouble in relaying our communications; indicated to us that the tires on the right hand side of the aircraft were still intact. They also indicated there was no sign of fire. There was however; a significant leak of what they assumed was hydraulic fluid coming from the right main gear. The APU was started and both engines were shut down. Before shutting down; I noted that there were absolutely no abnormal indications on the engine instruments; hydraulic pressure gauges; hydraulic quantity gauges; and the brake pressure gauge. For what seemed to us a fairly straightforward malfunction; communications became quite the challenge. It was difficult to simultaneously monitor and prioritize our communications with ATC (both tower and ground); company operations; dispatch (via ACARS); the crash crew on the scene; the flight attendants; and with each other (pilot to pilot). Tower also informed us after we had been on the ground for approximately 10 minutes that the violent airframe vibrations were blatantly obvious to tower personnel upon landing. There was also a significant amount of smoke from the right main mount as we were rolling out. A company mechanic eventually met the plane after an unexplained delay. He informed us that the scissors link on the right main mount was broken. He decided that we would be able to tow the aircraft back to the gate. Another threat to the aircraft came in some distracting systems issues as we were attempting to keep accurate information flowing into and out of the aircraft. Both air conditioning packs tripped off; leaving the cabin temperature to quickly rise above 90 degrees. Additionally; the APU failed to take the load of the #1 generator bus. A logbook entry was made describing the violent airframe vibrations after touchdown. We thoroughly debriefed the company mechanic on scene and company maintenance control of the associated systems malfunctions described above. We did not annotate these systems malfunctions in the logbook writeup. After discussing this with the captain; we feel that it might have been better to have been more detailed in the logbook writeup. We avoided doing this initially because we feltthat the debriefs with the mechanic and maintenance control were sufficient. We as the flight crew also felt that we were under some time pressure to press on to the next gate; get a new aircraft; and get on with the schedule. We consciously avoided being hurried; but felt that that environment was not optimum. The aircraft was towed back to the gate after an approximate total 45 minute delay. Upon deplaning; the flight attendants informed us that there were no passenger injuries. I think this event was an extremely rare mechanical failure that was handled well by the multiple parties involved.supplemental information from acn 789220: we as a flight crew felt pressured to get to the next gate where an aircraft was waiting for us to continue on to two more cities. At this time I called the chief pilot. He was very understanding and supportive. He informed me that I did not have to continue flying. With this decision left up to me; I felt like I was obligated to continue with my trip. As a pilot; I have no control over a major systems malfunctions and I believed this situation was handled extremely well by all parties involved. As far as the logbook entry; things were happening so fast; but I should have taken more time to make sure all entries were entered into the logbook.callback conversation with reporter 788983 revealed the following information: reporter stated the magnitude of the violent shaking of the B737-300 aircraft was the worst he has ever experienced. Even the control tower told him they could see the wings and especially the horizontal tail section violently oscillating at touchdown. Given the amount of vibration; the aircraft still maintained a fairly centered directional control on the runway. The oscillations became more violent as the aircraft speed decreased until approximately 20 knots. The flight attendants in the aft galley jump seats were physically shaken and visibly concerned after the incident. Surprisingly; all the overhead luggage bins remained closed and secured during the shaking. Reporter stated from what he could see of the right main landing gear scissor links; they appeared to be quite beaten-up; but did not seem to be separated at the forward end of the two links where they are attached by a single bolt. He believes the lower scissor link had broken at the main landing gear piston lower end; not at the gear strut housing. Both main gear tires were seriously worn. Reporter also stated there was a weight on wheels (wow) logic issue and other system malfunctions that seemed to have occurred. His carrier replaced the broken link and ferried the aircraft to their maintenance base to change the entire right main landing gear assembly.

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Original NASA ASRS Text

Title: A B737-300 FLIGHT CREW DESCRIBES THE SEVERE SHAKING; VIBRATING OSCILLATIONS OF THE ENTIRE AIRFRAME AT TOUCHDOWN. TOWER ALSO NOTICED ACFT SHAKING AND SMOKE. RT MAIN LANDING GEAR SCISSORS LINK HAD BROKEN.

Narrative: PLANNED VISUAL APPROACH. VMC WEATHER; WINDS 220 13G21. POSITIVE STOPPING MARGINS FOR ALL BRAKING LEVELS FOR BOTH RWYS XXR AND XXL. WHILE TURNING FINAL FROM A LEFT BASE; TOWER ASKED IF WE WOULD LIKE TO SWITCH TO RWY XXL. WE SAID YES AND WERE CLEARED TO LAND FROM MORE THAN 5 MILES FROM THE RUNWAY. CAPTAIN WAS PILOT FLYING. FLEW AN UNEVENTFUL VISUAL APPROACH TO RWY XXL WITH THE EXCEPTION OF SOME UNEXPECTED TURBULENCE/AIRSPEED FLUCTUATION AT APPROXIMATELY 300 FT AGL. PILOT FLYING APPLIED APPROPRIATE CORRECTION. JUST PRIOR TO TOUCHDOWN; PILOT FLYING APPLIED APPROPRIATE CROSSWIND CORRECTION AND AIRCRAFT LANDED ON CENTERLINE WITHIN THE FIRST 1000 FT OF THE TOUCHDOWN ZONE. IMMEDIATE SEVERE SHAKING/OSCILLATIONS OF ENTIRE AIRFRAME OCCURRED AT TOUCHDOWN. DIRECTIONAL CONTROL DID NOT SEEM TO BE AN ISSUE. THE SHAKING WAS EASILY THE MOST VIOLENT I HAVE EVER FELT IN AN AIRPLANE AND WOULD HAVE EQUATED TO SEVERE TURBULENCE HAD WE BEEN AIRBORNE. CAPTAIN AND I VERBALIZED SOMETHING TO THE EFFECT OF; 'I THINK WE BLEW A TIRE.' I WAS NOT ABLE TO UNDERSTAND ATC TRANSMISSIONS WHILE THE PLANE WAS SHAKING -- TOO MUCH AMBIENT NOISE. VIBRATIONS INCREASED IN INTENSITY UNTIL AIRCRAFT HAD SLOWED TO A NEAR COMPLETE STOP. CAPTAIN MAINTAINED RUNWAY CENTERLINE AND WAS ABLE TO STOP THE AIRCRAFT IN WHAT SEEMED A TYPICAL DISTANCE. THE CAPTAIN WAS ABLE TO TURN THE AIRCRAFT TO THE LEFT ONTO RWY XY; STOPPING NEAR THE INTERSECTION WITH TAXIWAY. ASSUMING THAT A TIRE HAD BLOWN; CAPTAIN INSTRUCTED ME TO TELL THE FLIGHT ATTENDANTS TO REMAIN SEATED. WE INITIALLY DECLINED TOWER'S REQUEST TO ROLL THE FIRE TRUCKS BECAUSE WE WERE UNDER THE ASSUMPTION THAT WE WERE SIMPLY DEALING WITH A BLOWN TIRE. VERY SHORTLY THEREAFTER; THE CAPTAIN RECONSIDERED AND WE ASKED TOWER TO ROLL THE FIRE TRUCKS. TRUCKS TOOK SEVERAL MINUTES TO ARRIVE; AND AFTER SOME TROUBLE IN RELAYING OUR COMMUNICATIONS; INDICATED TO US THAT THE TIRES ON THE RIGHT HAND SIDE OF THE AIRCRAFT WERE STILL INTACT. THEY ALSO INDICATED THERE WAS NO SIGN OF FIRE. THERE WAS HOWEVER; A SIGNIFICANT LEAK OF WHAT THEY ASSUMED WAS HYDRAULIC FLUID COMING FROM THE RIGHT MAIN GEAR. THE APU WAS STARTED AND BOTH ENGINES WERE SHUT DOWN. BEFORE SHUTTING DOWN; I NOTED THAT THERE WERE ABSOLUTELY NO ABNORMAL INDICATIONS ON THE ENGINE INSTRUMENTS; HYDRAULIC PRESSURE GAUGES; HYDRAULIC QUANTITY GAUGES; AND THE BRAKE PRESSURE GAUGE. FOR WHAT SEEMED TO US A FAIRLY STRAIGHTFORWARD MALFUNCTION; COMMUNICATIONS BECAME QUITE THE CHALLENGE. IT WAS DIFFICULT TO SIMULTANEOUSLY MONITOR AND PRIORITIZE OUR COMMUNICATIONS WITH ATC (BOTH TOWER AND GROUND); COMPANY OPERATIONS; DISPATCH (VIA ACARS); THE CRASH CREW ON THE SCENE; THE FLIGHT ATTENDANTS; AND WITH EACH OTHER (PILOT TO PILOT). TOWER ALSO INFORMED US AFTER WE HAD BEEN ON THE GROUND FOR APPROXIMATELY 10 MINUTES THAT THE VIOLENT AIRFRAME VIBRATIONS WERE BLATANTLY OBVIOUS TO TOWER PERSONNEL UPON LANDING. THERE WAS ALSO A SIGNIFICANT AMOUNT OF SMOKE FROM THE RIGHT MAIN MOUNT AS WE WERE ROLLING OUT. A COMPANY MECHANIC EVENTUALLY MET THE PLANE AFTER AN UNEXPLAINED DELAY. HE INFORMED US THAT THE SCISSORS LINK ON THE RIGHT MAIN MOUNT WAS BROKEN. HE DECIDED THAT WE WOULD BE ABLE TO TOW THE AIRCRAFT BACK TO THE GATE. ANOTHER THREAT TO THE AIRCRAFT CAME IN SOME DISTRACTING SYSTEMS ISSUES AS WE WERE ATTEMPTING TO KEEP ACCURATE INFORMATION FLOWING INTO AND OUT OF THE AIRCRAFT. BOTH AIR CONDITIONING PACKS TRIPPED OFF; LEAVING THE CABIN TEMPERATURE TO QUICKLY RISE ABOVE 90 DEGREES. ADDITIONALLY; THE APU FAILED TO TAKE THE LOAD OF THE #1 GENERATOR BUS. A LOGBOOK ENTRY WAS MADE DESCRIBING THE VIOLENT AIRFRAME VIBRATIONS AFTER TOUCHDOWN. WE THOROUGHLY DEBRIEFED THE COMPANY MECHANIC ON SCENE AND COMPANY MAINTENANCE CONTROL OF THE ASSOCIATED SYSTEMS MALFUNCTIONS DESCRIBED ABOVE. WE DID NOT ANNOTATE THESE SYSTEMS MALFUNCTIONS IN THE LOGBOOK WRITEUP. AFTER DISCUSSING THIS WITH THE CAPTAIN; WE FEEL THAT IT MIGHT HAVE BEEN BETTER TO HAVE BEEN MORE DETAILED IN THE LOGBOOK WRITEUP. WE AVOIDED DOING THIS INITIALLY BECAUSE WE FELTTHAT THE DEBRIEFS WITH THE MECHANIC AND MAINTENANCE CONTROL WERE SUFFICIENT. WE AS THE FLIGHT CREW ALSO FELT THAT WE WERE UNDER SOME TIME PRESSURE TO PRESS ON TO THE NEXT GATE; GET A NEW AIRCRAFT; AND GET ON WITH THE SCHEDULE. WE CONSCIOUSLY AVOIDED BEING HURRIED; BUT FELT THAT THAT ENVIRONMENT WAS NOT OPTIMUM. THE AIRCRAFT WAS TOWED BACK TO THE GATE AFTER AN APPROXIMATE TOTAL 45 MINUTE DELAY. UPON DEPLANING; THE FLIGHT ATTENDANTS INFORMED US THAT THERE WERE NO PASSENGER INJURIES. I THINK THIS EVENT WAS AN EXTREMELY RARE MECHANICAL FAILURE THAT WAS HANDLED WELL BY THE MULTIPLE PARTIES INVOLVED.SUPPLEMENTAL INFO FROM ACN 789220: WE AS A FLIGHT CREW FELT PRESSURED TO GET TO THE NEXT GATE WHERE AN AIRCRAFT WAS WAITING FOR US TO CONTINUE ON TO TWO MORE CITIES. AT THIS TIME I CALLED THE CHIEF PILOT. HE WAS VERY UNDERSTANDING AND SUPPORTIVE. HE INFORMED ME THAT I DID NOT HAVE TO CONTINUE FLYING. WITH THIS DECISION LEFT UP TO ME; I FELT LIKE I WAS OBLIGATED TO CONTINUE WITH MY TRIP. AS A PILOT; I HAVE NO CONTROL OVER A MAJOR SYSTEMS MALFUNCTIONS AND I BELIEVED THIS SITUATION WAS HANDLED EXTREMELY WELL BY ALL PARTIES INVOLVED. AS FAR AS THE LOGBOOK ENTRY; THINGS WERE HAPPENING SO FAST; BUT I SHOULD HAVE TAKEN MORE TIME TO MAKE SURE ALL ENTRIES WERE ENTERED INTO THE LOGBOOK.CALLBACK CONVERSATION WITH RPTR 788983 REVEALED THE FOLLOWING INFO: REPORTER STATED THE MAGNITUDE OF THE VIOLENT SHAKING OF THE B737-300 ACFT WAS THE WORST HE HAS EVER EXPERIENCED. EVEN THE CONTROL TOWER TOLD HIM THEY COULD SEE THE WINGS AND ESPECIALLY THE HORIZONTAL TAIL SECTION VIOLENTLY OSCILLATING AT TOUCHDOWN. GIVEN THE AMOUNT OF VIBRATION; THE ACFT STILL MAINTAINED A FAIRLY CENTERED DIRECTIONAL CONTROL ON THE RUNWAY. THE OSCILLATIONS BECAME MORE VIOLENT AS THE ACFT SPEED DECREASED UNTIL APPROX 20 KNOTS. THE FLIGHT ATTENDANTS IN THE AFT GALLEY JUMP SEATS WERE PHYSICALLY SHAKEN AND VISIBLY CONCERNED AFTER THE INCIDENT. SURPRISINGLY; ALL THE OVERHEAD LUGGAGE BINS REMAINED CLOSED AND SECURED DURING THE SHAKING. REPORTER STATED FROM WHAT HE COULD SEE OF THE RIGHT MAIN LNDG GEAR SCISSOR LINKS; THEY APPEARED TO BE QUITE BEATEN-UP; BUT DID NOT SEEM TO BE SEPARATED AT THE FORWARD END OF THE TWO LINKS WHERE THEY ARE ATTACHED BY A SINGLE BOLT. HE BELIEVES THE LOWER SCISSOR LINK HAD BROKEN AT THE MAIN LANDING GEAR PISTON LOWER END; NOT AT THE GEAR STRUT HOUSING. BOTH MAIN GEAR TIRES WERE SERIOUSLY WORN. REPORTER ALSO STATED THERE WAS A WEIGHT ON WHEELS (WOW) LOGIC ISSUE AND OTHER SYSTEM MALFUNCTIONS THAT SEEMED TO HAVE OCCURRED. HIS CARRIER REPLACED THE BROKEN LINK AND FERRIED THE ACFT TO THEIR MAINT BASE TO CHANGE THE ENTIRE RIGHT MAIN LANDING GEAR ASSEMBLY.

Data retrieved from NASA's ASRS site as of May 2009 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.