What do aircraft bolts marked with a cross or asterisk on the bolthead indicate?

Aircraft bolts marked with a cross or asterisk on the bolthead indicate that they are standard steel bolts. This marking is part of the identification system that helps differentiate various types of bolts used in aviation, ensuring appropriate material selection for structural integrity and performance. Standard steel bolts are widely used due to their strength and durability, making them suitable for many aircraft applications.

Understanding the significance of these markings is essential for maintenance and repair personnel, as using the correct type of bolt is critical for safety and compliance with aviation standards. Recognizing that the presence of a cross or asterisk specifically designates standard steel helps technicians make informed decisions when sourcing replacement parts or conducting inspections, maintaining the aircraft's reliability and airworthiness.