IRS Limitations

Question 1

Maximum acceptable difference between IRS position and MCDU position

Answer 1

5 Nm up to 1.5h block time but depends on the accumulated block hours (Chart SOP)

Question 2

Maximum latitudes to perform an IRS alignment

Answer 2

Some systems from 73°N/S and others from 82ºN/S

Question 3

In Nav mode, the IR will not provide valid magnetic heading and magnetic track angle

Answer 3

3 types of IRS depending on MSN:
-Type 1:
North of 73°N, between 90ºW and 120ºW
North of 82ºN
South of 60°S
-Type 2:
North of 70ºN, between 160ºW and 180ºW
North of 60ºN, between 30ºW and 160ºW
North of 75ºN
South of 55ºS
-Type 3:
North of 73ºN
South of 60ºS