Final answer:
Defects that can make aircraft unsafe for flight include engine malfunctions, navigation system failures, structural damage, fuel system leaks, and electrical system malfunctions.
Step-by-step explanation:
The defects that constitute hazardous or unsafe conditions in aircraft are those that can potentially make the aircraft unsafe for flight or endanger operating personnel. These defects can be identified through experience and judgment. Examples of such defects include:
- Engine malfunctions
- Navigation system failures
- Structural damage or weakness
- Fuel system leaks or failures
- Electrical system malfunctions
These defects can pose significant risks and need to be addressed before the aircraft is considered safe for flight.