I would agree that a CDFA appears to have been flown with GPS provided DME. Perhaps this is an example whereby dive-and-drive would have put him in a better position.
I wasn’t using GPS ILS, it was not necessary as I was on a published approach. I was doing CDFA based on the GPS range to touchdown.
The approach itself was absolutely fine, it was only the stupid decision not to continue with the MA once started that was the problem.
Perhaps this is an example whereby dive-and-drive would have put him in a better position.
Indeed…certainly Rod Machado would say so…
Anthony is there a link for Machado on CDFA?
Timothy thanks for pointing out it was a CDFA, I guess hard wiring the go around decision at MDA is a good take away from the accident.
It’s a pity they don’t organise RNAV GNSS approaches for airports like these.
RobertL18C wrote:
Anthony is there a link for Machado on CDFA?
https://www.aopa.org/news-and-media/all-news/2012/january/01/license-to-learn
Timothy wrote:
…it was only the stupid decision not to continue with the MA once started that was the problem.
In my experience the number of stupid (or “smart” as we would rather call them) decisions does not reduce with flying experience. But experience helps to get a lucky outcome from a bad decision in most cases. I would count this accident also as lucky outcome because no one was hurt. I never continued an approach after initating a go-around, but I “saved” a lot of unstable approaches each of which should have triggered an immediate go-around. Only multi-crew operation with strict SOPs can really prevent you from this kind of incident, ideally if you are not on friendliest terms with the other crew member.
Anthony thanks for posting the Machado link. The Flight Safety Foundation project ALAR project has always briefed the higher risk of non-precision approaches, especially with step downs for obstacle clearance.
http://flightsafety.org/current-safety-initiatives/approach-and-landing-accident-reduction-alar
I was not sure why Machado implies that there hasn’t been a problem with non precision approaches, which the CDFA was designed to mitigate. Instrument instructors might want to pitch in, but with a typical minima of around 1500m the simulator provides a good teaching environment why we have moved on from dive and drive. If you are not managing the descent to arrive at MDA at the design distance from the threshold, and you dive and drive, you will not acquire the runway environment with a 1500 m minima (too low and too far to pick up the approach lights, let alone PAPIs). You are now dragging an aircraft in with relatively poor lateral guidance (eg VOR or NDB) with no visual horizon, and with a consequent rise in the accident rate (study the ALAR link). This is before mistakes resulting from step downs where you are diving and driving to different step downs for obstacle clearance.
The CDFA does require better situational awareness and instrument skills as you are checking off that you are within +/- 100 feet off the target altitudes every 1 DME, while maintaining a stable Vref. Treating the MDA as a DA is synchronised, as this should occur at the point in space where you would be acquiring the PAPIs in any event, not searching for them in the murk.
Indeed… Note that Rod apparently does not like the terminology “dive and drive”….he seems to prefer “descend and track” per the US Airforce standard practice… FWIW I was taught CFDA and that is what I do…
Machado is right that if you screw up a CDFA it doesn’t work. Same applies to a DnD. I still prefer CDFA.
