Worst Case Analysis of Workload of the Cardiovascular System at the Current Shift Schedule of Fraport's Aircraft Ground Handling
Background / Objective
September 1, 2003 the agreement about the pilot project of personnel logistics was reached between Fraport AG and Fraport AG's work council. The objective of this project refers to a better adjustment of working times on the fluctuant occupational requirements as well as the wishes of individual working times of employees.
For this aim, a current status analysis is done of the present stress and strain as well as job satisfaction. After the introduction of a new working time schedule these parameters will be analyzed again and assessed according to the changes.
This report analyzes the current workload of staff members at the present shift schedule (module 1). Findings serve to compare the results of the new shift schedule (module 2). General aim of the workload analysis is to answer the following question:
- Are there conditions of overload concerning employees' health at the current shift system in a worst case scenario?
Surveyed employees of the aircraft ground handling perform a lot of tasks – next to parts of generally informational work are mainly energetic work (mixture of postural work, holding work, and heavy dynamic work).
Bottleneck systems of those workings are on the one side the cardiovascular system and on the other side the skeletal system (spinal column, hip and knee articulations).
The workload of the cardiovascular system is recorded by measuring the heart rate. The bottleneck of the skeletal system according to workload is gathered by subjective disorders of employees, and according to stress by the screening procedure of IAD-BkA (assessment of physical work).
The recording of the heart rate as an indicator for workload of the cardiovascular system showed that Q2-dispatcher, drivers, and loading master agents at mainly energetic work have a significant higher workload than at other tasks.
The exceeding of the endurance limit (absolute evaluation, cf. fig.) was the background of the workload assessment of the cardiovascular system at the current status of this survey (termination of module 1). The comparison of the old and new shift system according to a relative evaluation will be possible after the termination of module 2 “worst case analysis of workload of the cardiovascular system at the current shift schedule”.
For the assessment was it necessary to question how long the endurance limit was exceeded. The exceeding, as percentage of shift, was for Q2-dispatchers at 29.3%, for drivers at 13.4%, and for loading master agents at 22.1%. The next question was, if compensation would be possible by recovery breaks during the shift in order to make the work bearable.
A work is bearable, if exhaustion and recovery occurrences of the circulation are compensate during the shift.
The percentage of the work cycle related breaks of total time was at the present shift system at 49.3% (Q2-dispatcher), at 23.1% (drivers), and at 35.2% (loading master agents). The endurance was mainly between 1 and 5 minutes.
The temporary transgression of the endurance limits during the whole shift was compensated because of rest times. In general work process-related breaks are necessary. It is assumed that the reducing of these times is not possible in that way by organizational measurements, for example changing an employees' arrangement at another airplane at short notice, because of the mainly short breaks with endurance of 1 to 5 minutes. The short endurance of process-related breaks is from an ergonomic point of view positive in respect of an effective recovery. Based on ergonomic surveys on fatigue and recovery, it is known that diverse short breaks are more effective for recovery of the cardiovascular system than longer breaks. This knowledge is transferable for short breaks during work (that are no recesses because employees cannot freely decide about their timing).
The main aspects of work-related physical complaints concerned the areas of the shoulder and lumbar region (organization unit 4) or knee, shoulder, and lumbar region (organization unit 3).
The analysis of workload of the Q2-dispatchers with IAD-BkA showed a risk index RI_1 (cardio vascular system) of 2 – 3 (according to the computed values of 0.4 – 2). Hence the choice of an appropriate group of Q2-dispatchers (young, physically able to work under pressure) is necessary for the prevention of overloads and possible injuries.
The risk index RI_2 (skeletal system) was 3 – 4. This means a high value of workload, which indicates that even normal people under pressure would have a physical overload. Therefore, measurements for work design and behavior ergonomics are as well important in addition to a selected group of Q2-dispatchers.
Reasonable work design measurements concerning in this case the organizational work design (shift endurance, shift schedule, and shift sequences) because of freight weight, posture at work, for example in the belly, physical dimensions of the cargo bay, and factors of the surrounding such as weather influence and others, which are not modifiable.
The observed overloads during working time were long sequences of shifts (like in shift schedule 7-3-7-4). This is – from an ergonomic point of view – disadvantageously.
An open question is the ratio of fatigue and recovery phases as well as skeletal workload at variations of shift parameters (shift endurance, shift schedule, and shift sequences) of the new shift system (Findings of the survey module 2: comparative workload analysis of two different shift systems).