dream747
12th Aug 2010, 17:36
Hi everyone,
I remember reading a thread regarding this before some time ago but I just can't seem to find it now matter how I tried to search for it.
Anyway my question is, does the PFD on our modern jets today display IAS, CAS or EAS? Most people told me that it should be IAS or CAS but not EAS. Correct me if I am wrong, I understand that CAS is IAS corrected for position and instrument errors, and EAS is CAS corrected for compressibility error. Our Vspeeds are in CAS.
Which leads me to the question, say for example, our aircraft has a stalling speed of 200kts. Suppose we're flying at FL350 and should the PFD display IAS/CAS and is reading 220kts (for example), the error due to compressibility is not corrected for and EAS is actually 200kts. Wouldn't this be a danger as the pilot would think that he's 20kts away from stalling the airplane without knowing that he's closer to the stall than he actually thinks?
Many thanks for any inputs!:}
I remember reading a thread regarding this before some time ago but I just can't seem to find it now matter how I tried to search for it.
Anyway my question is, does the PFD on our modern jets today display IAS, CAS or EAS? Most people told me that it should be IAS or CAS but not EAS. Correct me if I am wrong, I understand that CAS is IAS corrected for position and instrument errors, and EAS is CAS corrected for compressibility error. Our Vspeeds are in CAS.
Which leads me to the question, say for example, our aircraft has a stalling speed of 200kts. Suppose we're flying at FL350 and should the PFD display IAS/CAS and is reading 220kts (for example), the error due to compressibility is not corrected for and EAS is actually 200kts. Wouldn't this be a danger as the pilot would think that he's 20kts away from stalling the airplane without knowing that he's closer to the stall than he actually thinks?
Many thanks for any inputs!:}