The subject of one of my two presentations at the CPI Symposium this past weekend was aviation maintenance. Within that presentation I used an analogy between what takes place in a hospital emergency room and what takes place in an unscheduled maintenance environment. In both scenarios I discussed a different type of Drum Buffer Rope (DBR) that Bruce Nelson and I referred to in our new book as Multiple Drum Buffer Rope (MDBR). In a typical DBR setting you have a single buffer feeding a single drum...otherwise known as the system constraint. MDBR differs in this respect. You still have a single buffer, but it's feeding multiple drums. Let me explain.
In the hospital scenario, patients come into an ER and are primarily either ill or injured. They are observed by doctors and nurses and many times tests are run to help with the diagnosis. When the diagnosis is complete, the patient is either treated in the ER and released or admitted to the hospital when a bed is available.
In an unscheduled maintenance of say, helicopters, during flight something is found to be wrong which makes the aircraft unflyable (just like patients in and ER). Mechanics, Inspectors and Avionics Technicians inspect the aircraft on the flightline to make a diagnosis, just like the ER. Once there is a diagnosis, the helicopter is either fixed on the flight line or it’s sent to an aircraft hangar for repair, just like patients get sent to different wards and beds.
I made this analogy so that the attendees at the symposium would have a good frame of reference when I discussed MDBR. In the hospital environment we have a buffer of patients waiting to have their ailment treated while in the unscheduled maintenance environment you have a buffer of helicopters waiting to be fixed. When a bed in the hospital becomes available a signal is sent to the ER and a patient is pulled into the right ward. When a hangar bay becomes available a signal is sent to pull a helicopter into that bay.
So what does this MDBR system look like graphically? The Figure below is the MDBR system as it applies to the hospital environment with the drum, the buffer and the rope.
The following figure is a depiction of an Unscheduled Maintenance MDBR and as you can see, there is no real difference between the two.
It seems as though the same application could apply to any situation where you have a common buffer feeding multiple lines regardless of the industry. This analogy seemed to ring true for the attendees.