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Part B - Verifications and approval requirements 
Assembly 
Test item 
Rotor blade 
Damage to the surface, cracks, structural inconsis 
tencies of the blade body. (Inspection from a lifting 
platform or climbing device or pulley system: Visual 
assessment and inspection of the structure using 
suitable processes (e.g. knocking, ultrasound)). Tigh 
tening torque of screw connections. Damage to light 
ning protection equipment. 
Drive train 
Leaks, unusual noises, condition of the corrosion 
protection, lubrication condition, tightening torque of 
screw connections. Condition of the gear unit 
Nacelle and power and torque-transmitting 
components 
Corrosion, cracks, unusual noises, lubrication condi 
tion, tightening torque of screw connections 
Hydraulic system, pneumatic system 
Damage, leaks, corrosion, function 
Safety equipment, measuring sensors and 
brake systems 
Function checks, compliance with limit values, 
damage, wear 
Documents 
Completeness, compliance with regulations, 
implementation, test documents, regular undertaking 
of maintenance, possibly including authorised 
modifications/repairs. 
Table 4-1 : Minimum requirements pertaining to the periodic inspection of the RNAs of offshore 
wind turbines. 
4.5.1 Requirements and required verifications 
4.5.1.1 Evaluation criteria for the periodic inspections 
The evaluation criteria for the periodic inspections shall be defined in the test and inspection 
plan according to the respective installation and site. 
4.5.1.2 Scope of the periodic inspections 
The stability against collapse of the RNA, including the function of the safety and brake sys 
tems, shall be inspected. The items covered by the periodic inspections are detailed in chap 
ter B2.5.3 (support structures for the RNA) and in Table 4-1 above. 
4.5.1.3 Periodic inspections - inspection intervals 
The periodic inspections of the RNA shall be carried out on at least 25 % of the wind turbines 
at the offshore wind farm so that all the RNAs are inspected in a four-year cycle. This period 
commences when trial runs are started. 
Based on empirical values and verification of the status through respective inspections, it is 
possibly to deviate from the prescribed annual test intervals in consultation with the appointed 
inspector and the BSH.