Narrative:

Aircraft X in jan/08 had a maintenance history report of fire at seat xx in armrest console. Source of fire was the lumbar seat control unit. This unit has been known to cause this condition by B/east aerospace lumbar seat control units. B/east service letter cites reliability issues with an earlier model shorting and burning when the domed spring clips shift and short across the contacts. Model upgrade was in dec/01. Old units are being replaced on attrition basis as units fail. When units fail they create heat; smoke and fire in the armrest of business class seats in 767 and 777 aircraft in air carrier's fleet. I first brought this to qa in late 2005 when we had our first fire at the gate with the airplane parked being readied for a revenue flight. This is a trend issue and not an isolated event. One in may/07 and another in apr/06 are two other specific examples of this occurrence. I heard of another incident in late nov/06 with a 767. The newer switches were introduced per air carrier part # XXXX. There was one burned unit in jun/04. These are in flight failure-smoke-fires on ETOPS flts occurring every 6 to eight months. Since air carrier qa and engineering have identified the problem with defective units; we should change out the defective units on an accelerated schedule so as not to have any more in-flight cabin smoke-fire incidents on ETOPS revenue flts in business class.callback conversation with reporter revealed the following information: reporter stated the lumbar seat control unit on the armrest has a membrane covering over the pushbutton dome spring switches. These spring switches become loose and slide across the contacts; arcing; shorting and then melting this membrane; causing heat; smoke and fire at the armrest. Reporter also stated a recent cabin incident of smoke and fire required the use of a portable halon fire bottle to extinguish the fire in the control unit. This control unit on the armrest can be removed by unlocking the unit using a small allen-type wrench; lifting the unit out of the armrest console and disconnecting the clip type electrical connector from the bottom of the controller. The cabin crew did not have this type of wrench on board. Having only spoons and plastic utensils; they attempted to remove the smoking pushbutton control pad from the seat armrest; but were not successful. Reporter further adds his company's quality assurance and engineering know of the problems; but have done little to expedite the removal of the older model control units still on-board their aircraft. Reporter also believes this is an industry issue affecting not only his carrier's fleet of B-777 and B-767; but other carriers' as well.

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Original NASA ASRS Text

Title: A TECHNICIAN RPTS OF IN-FLIGHT ETOPS ACFT RECURRING CABIN SMOKE; HEAT AND FIRE DUE TO THE FAILURE OF THE LUMBAR SEAT CTL UNIT IN THE ARMREST PUSHBUTTON CONSOLE. B767-300 AND B777-200 ACFT ARE AFFECTED.

Narrative: AIRCRAFT X IN JAN/08 HAD A MAINT HISTORY RPT OF FIRE AT SEAT XX IN ARMREST CONSOLE. SOURCE OF FIRE WAS THE LUMBAR SEAT CTL UNIT. THIS UNIT HAS BEEN KNOWN TO CAUSE THIS CONDITION BY B/E AEROSPACE LUMBAR SEAT CTL UNITS. B/E SERVICE LETTER CITES RELIABILITY ISSUES WITH AN EARLIER MODEL SHORTING AND BURNING WHEN THE DOMED SPRING CLIPS SHIFT AND SHORT ACROSS THE CONTACTS. MODEL UPGRADE WAS IN DEC/01. OLD UNITS ARE BEING REPLACED ON ATTRITION BASIS AS UNITS FAIL. WHEN UNITS FAIL THEY CREATE HEAT; SMOKE AND FIRE IN THE ARMREST OF BUSINESS CLASS SEATS IN 767 AND 777 AIRCRAFT IN ACR'S FLEET. I FIRST BROUGHT THIS TO QA IN LATE 2005 WHEN WE HAD OUR FIRST FIRE AT THE GATE WITH THE AIRPLANE PARKED BEING READIED FOR A REVENUE FLT. THIS IS A TREND ISSUE AND NOT AN ISOLATED EVENT. ONE IN MAY/07 AND ANOTHER IN APR/06 ARE TWO OTHER SPECIFIC EXAMPLES OF THIS OCCURRENCE. I HEARD OF ANOTHER INCIDENT IN LATE NOV/06 WITH A 767. THE NEWER SWITCHES WERE INTRODUCED PER ACR PART # XXXX. THERE WAS ONE BURNED UNIT IN JUN/04. THESE ARE IN FLT FAILURE-SMOKE-FIRES ON ETOPS FLTS OCCURRING EVERY 6 TO EIGHT MONTHS. SINCE ACR QA AND ENGINEERING HAVE IDENTIFIED THE PROBLEM WITH DEFECTIVE UNITS; WE SHOULD CHANGE OUT THE DEFECTIVE UNITS ON AN ACCELERATED SCHEDULE SO AS NOT TO HAVE ANY MORE IN-FLT CABIN SMOKE-FIRE INCIDENTS ON ETOPS REVENUE FLTS IN BUSINESS CLASS.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE LUMBAR SEAT CTL UNIT ON THE ARMREST HAS A MEMBRANE COVERING OVER THE PUSHBUTTON DOME SPRING SWITCHES. THESE SPRING SWITCHES BECOME LOOSE AND SLIDE ACROSS THE CONTACTS; ARCING; SHORTING AND THEN MELTING THIS MEMBRANE; CAUSING HEAT; SMOKE AND FIRE AT THE ARMREST. RPTR ALSO STATED A RECENT CABIN INCIDENT OF SMOKE AND FIRE REQUIRED THE USE OF A PORTABLE HALON FIRE BOTTLE TO EXTINGUISH THE FIRE IN THE CTL UNIT. THIS CTL UNIT ON THE ARMREST CAN BE REMOVED BY UNLOCKING THE UNIT USING A SMALL ALLEN-TYPE WRENCH; LIFTING THE UNIT OUT OF THE ARMREST CONSOLE AND DISCONNECTING THE CLIP TYPE ELECTRICAL CONNECTOR FROM THE BOTTOM OF THE CTLR. THE CABIN CREW DID NOT HAVE THIS TYPE OF WRENCH ON BOARD. HAVING ONLY SPOONS AND PLASTIC UTENSILS; THEY ATTEMPTED TO REMOVE THE SMOKING PUSHBUTTON CTL PAD FROM THE SEAT ARMREST; BUT WERE NOT SUCCESSFUL. RPTR FURTHER ADDS HIS COMPANY'S QUALITY ASSURANCE AND ENGINEERING KNOW OF THE PROBLEMS; BUT HAVE DONE LITTLE TO EXPEDITE THE REMOVAL OF THE OLDER MODEL CTL UNITS STILL ON-BOARD THEIR ACFT. RPTR ALSO BELIEVES THIS IS AN INDUSTRY ISSUE AFFECTING NOT ONLY HIS CARRIER'S FLEET OF B-777 AND B-767; BUT OTHER CARRIERS' AS WELL.

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.