<< >> NASA ASRS Report 595429, September 2003

A DC9-30 was dispatched in non compliance with a cleared deferred item on the left thrust reverser. Deactivation pin not removed during repair.

Attributes
ACN	595429
Time
Date	200309
Day	Mon
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	DC-9 30
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
Qualification	technician : airframe technician : powerplant
ASRS Report	595429
Person 2
Affiliation	company : air carrier
Function	maintenance : technician
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper documentation maintenance problem : improper maintenance non adherence : company policies non adherence : published procedure non adherence : far
Independent Detector	aircraft equipment other aircraft equipment : reverser position indication
Resolutory Action	none taken : detected after the fact
Consequence	other
Factors
Maintenance	contributing factor : manuals contributing factor : schedule pressure performance deficiency : repair performance deficiency : non compliance with legal requirements performance deficiency : logbook entry
Supplementary
Problem Areas	Chart Or Publication Maintenance Human Performance Aircraft
Primary Problem	Maintenance Human Performance
Situations
Publication	MEL

Narrative:

On sep/mon/03, I cleared a deferral for the l-hand thrust reverser accumulator low light, it was deferred. I removed the bypass pin from the hydraulic control valve and with another mechanic in the cockpit actuated the bypass lever while he monitored when the light was coming on and going off. As per the maintenance manual, the light was functioning properly. I visually inspected the switch and its connections without any defects noted. I then stowed the bypass pin and closed the access door. I thought I was working with a hydraulic latched thrust reverser, but it was actually mechanically latched. Mechanically latched, thrust reversers have an additional step to install an additional safety pin, which I failed to remove, and on the first flight of the day, the thrust reversers did not deploy. I think possibly a placard describing it a thrust reversers is mechanical or hydraulic could be beneficial.

Related reports:

• A B767-300 was dispatched in non compliance with a deferred ...

	Enter your search terms Submit search form
	Web www.37000feet.com

Original NASA ASRS Text

Title: A DC9-30 WAS DISPATCHED IN NON COMPLIANCE WITH A CLRED DEFERRED ITEM ON THE L THRUST REVERSER. DEACTIVATION PIN NOT REMOVED DURING REPAIR.

Narrative: ON SEP/MON/03, I CLRED A DEFERRAL FOR THE L-HAND THRUST REVERSER ACCUMULATOR LOW LIGHT, IT WAS DEFERRED. I REMOVED THE BYPASS PIN FROM THE HYD CTL VALVE AND WITH ANOTHER MECH IN THE COCKPIT ACTUATED THE BYPASS LEVER WHILE HE MONITORED WHEN THE LIGHT WAS COMING ON AND GOING OFF. AS PER THE MAINT MANUAL, THE LIGHT WAS FUNCTIONING PROPERLY. I VISUALLY INSPECTED THE SWITCH AND ITS CONNECTIONS WITHOUT ANY DEFECTS NOTED. I THEN STOWED THE BYPASS PIN AND CLOSED THE ACCESS DOOR. I THOUGHT I WAS WORKING WITH A HYD LATCHED THRUST REVERSER, BUT IT WAS ACTUALLY MECHANICALLY LATCHED. MECHANICALLY LATCHED, THRUST REVERSERS HAVE AN ADDITIONAL STEP TO INSTALL AN ADDITIONAL SAFETY PIN, WHICH I FAILED TO REMOVE, AND ON THE FIRST FLT OF THE DAY, THE THRUST REVERSERS DID NOT DEPLOY. I THINK POSSIBLY A PLACARD DESCRIBING IT A THRUST REVERSERS IS MECHANICAL OR HYD COULD BE BENEFICIAL.

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