Narrative:

Left-hand engine forward jet pipe insulation blanket not installed during c-chk. During aircraft a-chk; a mechanic noticed the insulation blankets were missing on the #1 engine forward jet pipe. Investigation revealed that all steps for installation of the jet pipe and shrouds were accomplished; except a warning was overlooked to make sure the insulation blankets were properly installed prior to installation of the forward jet pipe. The jet pipe was replaced during the (previous) c-chk and the replacement (component) did not come as an assembly; it came without blankets. A maintenance manual 'warning' was missed; perhaps the next installation step should have repeated most of the warning. Removed and replaced forward #1 engine jet pipe assembly; which includes the insulation blanket. Callback conversation with reporter revealed the following information: the jet pipe is attached to the engine aft case with a split flange type clamp assembly. The replacement shroud around the jet pipe normally comes with insulation blankets attached. These blankets are secured with safety wire to the shroud. However; this shroud unit did not come with insulation installed. This aircraft flew approximately for a week before line inspection noticed the blankets were missing. When the shroud was replaced; the maintenance warning notice was overlooked (not recognized) as part of the installation sign-offs on the work card.

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Original NASA ASRS Text

Title: A DHC8-200 ACFT LEFT ENGINE FWD JET PIPE INSULATION BLANKET NOT INSTALLED DURING C-CHECK.

Narrative: L-HAND ENG FORWARD JET PIPE INSULATION BLANKET NOT INSTALLED DURING C-CHK. DURING ACFT A-CHK; A MECH NOTICED THE INSULATION BLANKETS WERE MISSING ON THE #1 ENG FORWARD JET PIPE. INVESTIGATION REVEALED THAT ALL STEPS FOR INSTALLATION OF THE JET PIPE AND SHROUDS WERE ACCOMPLISHED; EXCEPT A WARNING WAS OVERLOOKED TO MAKE SURE THE INSULATION BLANKETS WERE PROPERLY INSTALLED PRIOR TO INSTALLATION OF THE FORWARD JET PIPE. THE JET PIPE WAS REPLACED DURING THE (PREVIOUS) C-CHK AND THE REPLACEMENT (COMPONENT) DID NOT COME AS AN ASSEMBLY; IT CAME WITHOUT BLANKETS. A MAINT MANUAL 'WARNING' WAS MISSED; PERHAPS THE NEXT INSTALLATION STEP SHOULD HAVE REPEATED MOST OF THE WARNING. REMOVED AND REPLACED FORWARD #1 ENG JET PIPE ASSEMBLY; WHICH INCLUDES THE INSULATION BLANKET. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE JET PIPE IS ATTACHED TO THE ENGINE AFT CASE WITH A SPLIT FLANGE TYPE CLAMP ASSEMBLY. THE REPLACEMENT SHROUD AROUND THE JET PIPE NORMALLY COMES WITH INSULATION BLANKETS ATTACHED. THESE BLANKETS ARE SECURED WITH SAFETY WIRE TO THE SHROUD. HOWEVER; THIS SHROUD UNIT DID NOT COME WITH INSULATION INSTALLED. THIS ACFT FLEW APPROX FOR A WEEK BEFORE LINE INSPECTION NOTICED THE BLANKETS WERE MISSING. WHEN THE SHROUD WAS REPLACED; THE MAINT WARNING NOTICE WAS OVERLOOKED (NOT RECOGNIZED) AS PART OF THE INSTALLATION SIGN-OFFS ON THE WORK CARD.

Data retrieved from NASA's ASRS site as of January 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.