Question about an NDB approach
In the SIM today we were to do a let down using an NDB approach, not NDB/DME or any other chart structure, just NDB. It was timed 3 minutes outbound descending to an intermediate altitude, a proceedure turn and then down to the MDA on the inbound leg. The Missed approach point was defined by a DME fix ! There were no timing V's G/S or any other cross check, just this DME fix.
Question 1 How can this chart be defined as just a NDB chart and not an NDB/DME letdown ?
The instructor then failed the DME halfway down the proceedure.
Question 2 Can you continue to the MDA or must you abandon the approach then ? There were no other published cross checks for the MAP even though we had a GPS which was probably more accurate than the DME (?).
Practical approach might be to use a conservative GPS position as an alternative, but whats the 'legal' answer to this question ?