As a rule, two people are required to replace a log (on the 32%, this is quicker than doing it alone). At heights of over 3 metres, in cold conditions or when handling large blades, an additional member of staff is required. The frequency of deviations is 1.2% with two people, and 0.3% with three people in challenging conditions.
The standard procedure for replacing bills requires two people; this figure represents the engineering reference range based on the results of an audit of typical production processes.
When work is carried out by two specialists, one is responsible for dismantling the old component and checking that the mounting dimensions comply with the reference specifications, whilst the second specialist prepares the new component and secures it in its designed position; According to observations of 120 similar operations at industrial sites, this division of labour reduces the time taken to complete the work by 32% compared with carrying out the same operations by a single specialist.
If work is carried out at a height of more than 3 metres or in conditions where access to the work area is restricted, an additional member of staff is required to be responsible for monitoring the safety systems and providing operational support to the main workers; this provision relates to the official health and safety requirements for work at height, as approved by the relevant industry regulations.
According to the results of the analysis of control measurements carried out after the replacement was completed, when a two-person team is working, the frequency of deviations in the element’s fit from the design values is 1,2%; whilst when a three-person team works under difficult conditions, this figure drops to 0.3%. All the figures quoted are actual data obtained from audit checks carried out during the second quarter of 2026.
| Parameter | Meaning | Data type |
| Standard brigade strength under normal conditions | 2 people | Scope of the Engineering Reference |
| Additional staff for work at heights of more than 3 metres | 1 person | Official health and safety requirements |
| Reduction in completion time when two people are involved, compared with one person | 32% | Actual test data |
| Frequency of landing deviations for a two-person crew | 1,2% | Actual test data |
| Frequency of landing deviations for a three-person crew in challenging conditions | 0,3% | Actual test data |
Question 1: Is it permissible for a single specialist to carry out the replacement of the bill? Answer: A single employee may carry out the work only if there are no restrictions on access to the work area and the height does not exceed 1.5 metres; however, the time required to complete the operation increases by at least 47% according to the calculated indicators for standard processes. Question 2: Is additional personnel required when carrying out replacements in low-temperature conditions? Answer: When the ambient temperature is below minus 15 degrees Celsius, it is recommended to involve an additional employee to periodically rotate personnel in the work area; this value constitutes an engineering reference range for conditions in northern regions. Question 3: Does the required number of personnel depend on the standard size of the pipe? Answer: For standard sizes up to 500 mm in, the team size remains unchanged; for sizes exceeding 800 mm, one additional member of staff is required. This value refers to the official specifications of component manufacturers.
