Working cvr
Wynsoc
There has already been a fatal cfit with a working cvr, some years ago, in a westwind freighter at Alice Springs.
There are a number of lessons that we should have learned from it, but obviously we did not.
A two pilot crew was flying a triple ndb approach, which had a bend in it, but was depicted on the plate as a straight line. I have flown that approach, and it was almost unflyable (within tolerances). The captain had flown that approach on a previous occasion, and had not been happy with his tracking tolerances.
On this occasion (on a clear night) the captain was flying the aircraft, and his pre-approach brief included a minimum altitude, which was correct. But during the approach while the captain was flying, the co-pilot called an incorrest minimum altitude, which was lower than the minimum altitude the captain had nominated himself during the brief. Despite this, the captain descended and the cfit occurred.
Why??
The captain was obviously distracted by something and appears to have lost altitude awareness. I think it is a reasonable assumption that he was concentrating on trying to track within tolerance. The required tracking tolerance was +/- 5 degrees, and the approach had a built in 4 degree error.
The ATSB report criticised the captain for not maintaining the track within 5 degrees.
This approach was fairly new, and was quickly discontinued.
The two pilot crew system did not detect and rectify the altitude error.
It was a clear night, and the appraoch could have been flown safely visually. Alice Springs had a TVASI which is visible from the crash site and beyond.
There are some similarities with the lockhart river accident.
Both were two crew turbine powered aircraft, but did the two crew system work properly during the approach? Was there effective cross checking? The co-pilot at lockhart river was not qualified for the approach being flown. There is some doubt about the clarity of the approach plates, and the possibility of error when reading distances and altitudes, in both accidents.
There are still many unknowns with the lockhart river accident, and I do not pretend to have the answers. But I do believe there are similarities and lessons to be learned from these accidents, and I hope we learn them,.And act on them this time.