Operations Research: Single Airbase Logistics Model (SALOMO)


Single Airbase Logistics Model (SALOMO)

By commission of the Royal Netherlands Air Force (RNLAF), TNO-FEL developed the Single Airbase LOgistics MOdel (SALOMO) program to support RNLAF policy on F-16 aircraft. SALOMO simulated the main logistic processes for servicing F-16 jet fighters at an airbase during peacetime and provided better insight into the effects that these processes have on the performance of the airbase.

Two important requirements must be met during peacetime. First, each pilot has to fly an annual program to maintain a sufficient level of proficiency, and second, a certain percentage of the NATO-designated F-16s must be ‘Mission Capable’. These requirements may conflict. On the one hand, the use of F-16s is necessary to realise the annual flying program of the pilots. On the other hand, the use of F-16s induces faults and consequently reduces the ‘Mission Capability’.
To achieve the aforementioned, the operational processes utilisation (i.e. flying) and preparation (i.e. loading, fuelling, and rerolling) must be well supported by the logistic processes maintenance (i.e. periodical inspections and repairs) and spare parts supply. Due to the strong interaction between these processes, predicting the consequences of management decisions regarding F-16 maintenance and utilisation processes is hard. Hence TNO-FEL built the simulation model SALOMO to predict several important performance results of an airbase, e.g. the number of flying hours per pilot and the percentage of mission-capable F-16s.
SALOMO could be used to investigate the relations among the operational and logistic processes and to compare some possible maintenance and utilisation policies. The various alternatives could be simulated by varying the input parameters that influence them. As a result, SALOMO provided a better insight into the effects that these processes have on both the deployment level of the F-16s and the proficiency level of the pilots, thus supporting the management of an airbase.

The SALOMO program had three modules:

  • the input module
  • the simulation module
  • the output module
SALOMO input module
SALOMO input module

The user could build an ‘airbase’ by specifying the input parameters that influence the four main processes: utilisation, preparation, maintenance, and spare parts supply. Some examples of these parameters are the number of maintenance personnel, the shifts, malfunction probabilities, airbase layout (e.g. the number of docks), flight schedule (e.g. waves and commitments), and the strategy for ordering and repairing spare parts.
The simulation module simulated the four processes ‘maintenance’, ‘utilisation’, ‘preparation’, and ‘spare parts supply’ based upon the provided input parameters.
Finally, the output module enabled the user to analyse the expected performance of the airbase. For this purpose, several categories of output data could be displayed that could be viewed on a daily, weekly, monthly, or yearly basis.

Monthly state
Monthly state

The most important results regarding the performance of the airbase are of course the percentage of mission-capable aircraft and the number of flying hours per pilot. Some other useful results for analysing the processes were the occupation level of the personnel and the partition of the percentage of ‘Not Mission Capable (NMC)’ into the percentage of NMC due to maintenance, NMC due to personnel, NMC due to location and NMC due to spare parts.

Salomo output
Salomo output

SALOMO is used mainly by the RNLAF headquarters and airbases as a decision support system for F-16 maintenance and utilisation policies. SALOMO could be used to predict the effects of measures that might influence the performance of an airbase, e.g. personnel measures, building extra maintenance docks, out-of-area operations, or a change in the flight schedule.
Moreover, the Netherlands Defence College used SALOMO for educational purposes. Students could calculate and analyse the effects of several airbase operation alternatives. They acquired insight into the relations between logistic and operational processes at an airbase.
Around 2000, TNO started developing a SALOMO version suitable for helicopters, in particular the Apache.