An apparatus (400; 500) suitable for dislodging material within an airfoil element (200; 300), comprising: a mounting head ; a robotic arm configured for multi-axis movement of the mounting head with respect to the airfoil element (200; 300); a vibration mechanism (408; 508) connected to the mounting head ; and a tip member (412; 512) connected to the vibration mechanism (408; 508) and configured for vibratory contact with a surface of the airfoil element (200; 300), characterised in that the apparatus (400; 500) further comprises: a pneumatic cylinder connected to the vibration mechanism (408; 508) and configured to maintain the tip member (412; 512) against the surface of the airfoil element (200; 300); and a sub-atmospheric pressure source connected by a pneumatic supply line to the pneumatic cylinder , wherein the pneumatic cylinder includes a rod connected to the mounting head and is configured to translate the tip member (412; 512) in an axial direction (A) with respect to the rod , wherein the robotic arm is configured to translate the tip member (412; 512) against the surface of the airfoil element (200; 300) in a spanwise direction (S), between a base portion and a blade tip of the surface of the airfoil element (200; 300), and in a chordwise direction (C), between a leading edge portion and a trailing edge portion of the surface of the airfoil element (200; 300) while applying a vibratory motion against the rotor blade . a mounting head ; a robotic arm configured for multi-axis movement of the mounting head with respect to the airfoil element (200; 300); a vibration mechanism (408; 508) connected to the mounting head ; and a tip member (412; 512) connected to the vibration mechanism (408; 508) and configured for vibratory contact with a surface of the airfoil element (200; 300), characterised in that the apparatus (400; 500) further comprises: a pneumatic cylinder connected to the vibration mechanism (408; 508) and configured to maintain the tip member (412; 512) against the surface of the airfoil element (200; 300); and a sub-atmospheric pressure source connected by a pneumatic supply line to the pneumatic cylinder , wherein the pneumatic cylinder includes a rod connected to the mounting head and is configured to translate the tip member (412; 512) in an axial direction (A) with respect to the rod , wherein the robotic arm is configured to translate the tip member (412; 512) against the surface of the airfoil element (200; 300) in a spanwise direction (S), between a base portion and a blade tip of the surface of the airfoil element (200; 300), and in a chordwise direction (C), between a leading edge portion and a trailing edge portion of the surface of the airfoil element (200; 300) while applying a vibratory motion against the rotor blade . a pneumatic cylinder connected to the vibration mechanism (408; 508) and configured to maintain the tip member (412; 512) against the surface of the airfoil element (200; 300); and a sub-atmospheric pressure source connected by a pneumatic supply line to the pneumatic cylinder , wherein the pneumatic cylinder includes a rod connected to the mounting head and is configured to translate the tip member (412; 512) in an axial direction (A) with respect to the rod , wherein the robotic arm is configured to translate the tip member (412; 512) against the surface of the airfoil element (200; 300) in a spanwise direction (S), between a base portion and a blade tip of the surface of the airfoil element (200; 300), and in a chordwise direction (C), between a leading edge portion and a trailing edge portion of the surface of the airfoil element (200; 300) while applying a vibratory motion against the rotor blade . <EOS>