Large transport drifts off runway and comes to stop on the grass.

Attributes
ACN	88920
Time
Date	198806
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : sea
State Reference	WA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 200 flight time total : 4700 flight time type : 200
ASRS Report	88920
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 7000 flight time type : 5200
ASRS Report	88916
Events
Anomaly	aircraft equipment problem : critical other anomaly other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

After a normal approach and T/D, I called out 3 reverser lights and observed the plane drifting to the left. As the landing roll progressed, the plane continued to drift left as we approached the side of the runway. The aircraft exited the runway and into the weeds before coming to a stop. The captain immediately ordered an evacuate/evacuation which I passed on to the F/a's. We then smoothly accomplished the emergency evacuate/evacuation checklist and I assured all passengers were safely off the aircraft. Supplemental information from acn 88916. A normal T/D on main gear, deploying all engines into idle reverse I felt an immediate yaw to the left. Callback conversation with reporter acn 88920 revealed following information. Reporter said that the official results of the investigation were that there had been a failure of the number 2 reverser. Only 'half of the reverser had deployed' causing side thrust that could not be overcome by brakes and other control measures.

Original NASA ASRS Text

Title: LGT DRIFTS OFF RWY AND COMES TO STOP ON THE GRASS.

Narrative: AFTER A NORMAL APCH AND T/D, I CALLED OUT 3 REVERSER LIGHTS AND OBSERVED THE PLANE DRIFTING TO THE LEFT. AS THE LNDG ROLL PROGRESSED, THE PLANE CONTINUED TO DRIFT LEFT AS WE APCHED THE SIDE OF THE RWY. THE ACFT EXITED THE RWY AND INTO THE WEEDS BEFORE COMING TO A STOP. THE CAPT IMMEDIATELY ORDERED AN EVAC WHICH I PASSED ON TO THE F/A'S. WE THEN SMOOTHLY ACCOMPLISHED THE EMER EVAC CHKLIST AND I ASSURED ALL PAXS WERE SAFELY OFF THE ACFT. SUPPLEMENTAL INFO FROM ACN 88916. A NORMAL T/D ON MAIN GEAR, DEPLOYING ALL ENGS INTO IDLE REVERSE I FELT AN IMMEDIATE YAW TO THE LEFT. CALLBACK CONVERSATION WITH RPTR ACN 88920 REVEALED FOLLOWING INFO. RPTR SAID THAT THE OFFICIAL RESULTS OF THE INVESTIGATION WERE THAT THERE HAD BEEN A FAILURE OF THE NUMBER 2 REVERSER. ONLY 'HALF OF THE REVERSER HAD DEPLOYED' CAUSING SIDE THRUST THAT COULD NOT BE OVERCOME BY BRAKES AND OTHER CONTROL MEASURES.

Data retrieved from NASA's ASRS site as of August 2007 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.