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## IREX Book Revision Exercise 2.1 Q4

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### elizabeth created the topic: IREX Book Revision Exercise 2.1 Q4

Hi,

Question 4 is asking about whether a flight can continue given a faulty altimeter reading.

In the first instance at Archerfield the altimeter is only incorrectly reading by 45 ft. YBAF AD ELEV 65FT. Altimeter reads 110FT. This is within tolerance for IFR flight with one altimeter.

In the second instance at Rockhampton the altimeter is incorrectly reading by 64ft. YBRK AD ELEV 36FT and altimeter reads 100FT. This puts it over the 60 ft error limit.

BUT according to AIP ENR 1.7 para 1.2.4 "When an aircraft is fitted with only one altimeter and that altimeter has an error between 60FT and 75FT, flight under the IFR to the first point of landing, where the accuracy of the altimeter can be re-checked, is approved. In the event that that the altimeter shows an error in excess of 60FT in the second check the altimeter is to be considered unserviceable for flight under the IFR."
Therefore the flight COULD proceed to Mackay as an IFR flight as the first altimeter check would be in Rockhampton where the error in excess of 60FT first eventuates. Mackay would be considered the first point of landing.

The answer in the book says the altimeter is out of limits for IFR operations and to continue to Mackay, it must be under VFR.

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### domcheung replied the topic: IREX Book Revision Exercise 2.1 Q4

elizabeth wrote: Hi,

Question 4 is asking about whether a flight can continue given a faulty altimeter reading.

In the first instance at Archerfield the altimeter is only incorrectly reading by 45 ft. YBAF AD ELEV 65FT. Altimeter reads 110FT. This is within tolerance for IFR flight with one altimeter.

In the second instance at Rockhampton the altimeter is incorrectly reading by 64ft. YBRK AD ELEV 36FT and altimeter reads 100FT. This puts it over the 60 ft error limit.

BUT according to AIP ENR 1.7 para 1.2.4 "When an aircraft is fitted with only one altimeter and that altimeter has an error between 60FT and 75FT, flight under the IFR to the first point of landing, where the accuracy of the altimeter can be re-checked, is approved. In the event that that the altimeter shows an error in excess of 60FT in the second check the altimeter is to be considered unserviceable for flight under the IFR."
Therefore the flight COULD proceed to Mackay as an IFR flight as the first altimeter check would be in Rockhampton where the error in excess of 60FT first eventuates. Mackay would be considered the first point of landing.

The answer in the book says the altimeter is out of limits for IFR operations and to continue to Mackay, it must be under VFR.

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### elizabeth replied the topic: IREX Book Revision Exercise 2.1 Q4

Got it! Thanks for pointing it out!

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### bobtait replied the topic: IREX Book Revision Exercise 2.1 Q4

The altimeter is checked against the threshold elevation, not the aerodrome elevation. That makes the error greater than 60ft at Archerfield.
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### elizabeth replied the topic: IREX Book Revision Exercise 2.1 Q4

Thank you for clarifying that Bob!

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