Simple RCA: Scenario # 2

Overhead Bridge Crane Leaky Valve

Timeline Analysis Exercise

While the Facility Manager was completing a safety walk down of the high bay he found oil on the floor and on some flight hardware. He called the technician over and asked him why there was oil on the floor and hardware. The technician indicated that it was due to a leaky valve in the pipe from the over-head bridge crane above. The Facility Manager then asked when the valve had been replaced and the technician responded he had installed 3 new valves over the past 8 weeks, and each time, shortly after installation, the valve would leak oil. The technician also indicated that Quality Assurance (QA) personnel had inspected the lot of valves after the 3rd leak, and had found that the earlier shipment contained a substantial number of defective valves. QA spoke with purchasing to inform them that the valves were bad. The technician indicated that he waited until a new shipment was received at the site before he replaced the valve. To his knowledge the new shipment was good. The technician installed the 3rd valve from this new shipment. Shortly thereafter the 3rd valve leaked.

The Facility Manager then went to talk with purchasing about the valves. The Purchasing Manager indicated that they had in fact received a bad batch of valves from the supplier some time ago. The Purchasing Manager also indicated that after the Quality Assurance employee spoke with him, he sent a letter to the supplier requesting new replacement valves. The valves came in, but still did not meet the specifications. The Purchasing Manager indicated that often components from this supplier were sub-standard. The Facility Manager then asked the Purchasing Manager why they had purchased from this supplier if they had a problem with the product quality. The Purchasing Manager indicated that there was a standard policy that indicated they must select the lowest bidder. The Purchasing Manager wanted to meet his customer’s most valued requirements, saving money, so he continued to use this supplier. Timeline (From Left to Right) Make sure students use Actor, Verb and Descriptor (Actor = highlight, Verb = Underline)

1) Overhead bridge crane valve leaked oil onto highbay floor - 1st time 2) Technician replaced valve in overhead bridge crane pipe - 1st time 3) Overhead bridge crane valve leaked oil 2nd time onto highbay floor. 4) Technician replaced valve 2nd time. 5) Overhead bridge crane valve leaked oil 3rd time onto highbay floor. 6) Quality assurance professional inspected the lot of valves. 7) Substantial number of valves were defective. (Condition) 8) Quality assurance professional informed purchasing of defective valves. 9) Purchasing manager ordered replacement valves. 10) Valves arrived on site. 11) Valves were out of specification (Condition) 12) Technician installed defective valve (from new lot) to replace leaking valve the 3rd time 13) Overhead bridge crane valve leaked oil 4th time onto highbay floor. 14) Facility manager detected leak during a walk down of the highbay.

What is the top box (undesired outcome)?

Oil on highbay floor that has the potential to cause a slip/trip or fall or damage flight hardware.

What are the proximate causes 1) Technician installed defective valve after 3rd oil leak from overhead bridge crane 2) Overhead bridge crane valve leaked oil onto highbay floor the 4th time. a) Valves were defective (Condition) i) Purchasing manager selected lowest bidder (1) Purchasing Manager met customer’s most valued requirements, saving money 3) Facility manager detected leak during a walk down of the highbay. Questions: What was the undesired outcome? Oil on Flight Hardware costing $? Oil was on highbay floor - potential to cause a slip/trip or fall.

What was the control?: Facility manager walked through the highbay.

Name one condition: The valves were defective.

Make a 4-column list. What do you know, and what do you need to know to complete the RCA?