• For the intervals between maintenance work, a tolerance of ±10 hr. is permissible, butthese tolerances must not be exceeded. This means that if a 100 hr. check is actuallycarried out at 110 hr., the next check will be due at 200 hr. ±10 hr. and not at 210 hr. ±10hr.• If maintenance is performed before the prescribed interval, the next maintenance checkis to be done at the same interval (e.g. if first 100 hr. check is done after 87 hours of operation, the next 100 hr. check must be carried out after 187 hours of operation).• If engine has less than 100 hours of operation during one year a 100 hr. check must becarried out. For the annual inspection a tolerance of ±2 months is given.