Date: 201503
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Citation Excel (C560XL)
Operator: Fractional
Operating under: Part 135
Flight phase: Parked
Aircraft component: DC Battery
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Situational Awareness; Training / Qualification; Communication Breakdown
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Detector: Person Maintenance
When detected: Routine Inspection
Result: General Maintenance Action
Contributing factors: Incorrect / Not Installed / Unavailable Part; Procedure; Human Factors
Primary problem: Human Factors

Narrative: Battery not assembled properly; installed [inner liner] blocking vent; causing no air flow. Battery deep cycled at [alternate] Repair Facility January 2015. Evidence of electrolyte leakage. Potassium carbonates (white deposits) on top of all cells; down the inside of case and wedges (spacers). [Recommend] Quality Checks and check work over [again]. Testing. During general overhaul in Shop.  General overhaul [of battery] I.A.W. Battery Manufacturer's Operating Maintenance Manual (OMM) 24.30.99  Revision January 2015.

Callback: Reporter stated he works for a Fractional operator that also repairs aircraft batteries. He was asked to remove an aircraft battery from the tail section of a Cessna Citation 560XL that was written up for being very warm. In their Repair Shop; the top of the Ni-Cad battery was removed and the plastic type inner liner on the inside of the battery's outer case was found to have extended all the way up to the lower side of the battery case top. During normal build of the battery; the plastic liner does not extend all the way to the top and provides a necessary gap for venting of the battery. The plastic liner separates the battery cells from the metal outer case. Not all batteries have a liner that completely surrounds the battery cells inside the outer case. Some batteries have spacers under the cells to separate them from the bottom of the battery.Reporter stated a sticker on the battery indicated the Ni-Cad battery had been through a Deep-Cycle Check where the battery is subjected to a 12 to 16 hour draw-down of power. Batteries do retain some heat during the draw down and the average six to eight hours that it takes to charge them back up to normal. But; since the gap inside the battery at the top did not exists and proper heat venting was not occurring; questions were raised as to whether the other Repair Station did actually perform the draw-down test properly; shortened the test; or if the battery was subjected to high thermal heat. The question of who actually built-up the battery has not been answered yet. Not all battery build-ups require a 'Second Set of Eyes' inspection prior to closing the top of batteries.



Synopsis: An Aircraft Maintenance Technician (AMT) removed a Ni-Cad battery from the tail section of a Cessna Citation 560XL that had been written-up for being very warm. A plastic inner liner installed during battery build-up; which separates the cells from the battery outer case; had improperly extended all the way to the top of the battery and closed off a normal gap required for venting.