Dundee Baron G-RICK Crash - May 2015 Accident Report

@Peter

what are those “certain things”? It is one of the main purposes of such a system to prevent you from flying into the ground on an IAP. After all it’s a class B EGPWS system.

Class B TAWS is defined by the U.S. FAA as:211 A class of equipment that is defined in TSO-C151b and RTCA DO-161A.12 As a minimum, it will provide alerts for the following circumstances:

- Reduced required terrain clearance
- Imminent terrain impact
- Premature descent
- Excessive rates of descent
- Negative climb rate or altitude loss after takeoff
- Descent of the airplane to 500 feet above the terrain or nearest runway elevation (voice callout “Five Hundred”) during a non-precision approach.
- Optional: Class B TAWS installation may provide a terrain awareness display that shows either the surrounding terrain or obstacles relative to the airplane, or both.

Well, they didn’t have it, so short of running their track on a sim of an aircraft with some GPWS box installed, this is hypothetical.

Very few planes have this, because of the cost. And the ongoing database cost; I know most private pilots don’t update their database after the initial purchase.

Peter wrote:

But with a non-GPS approach (ILS NDB VOR etc) there is no database so the “system” knows nothing about where you are on a procedure. It is not even aware you are flying a procedure. No procedure is loaded. The act of flying a procedure is wholly in the pilot’s mind.

Not quite true Peter. On something like a G1000 an ILS is loaded the same way as a GPS approach. And you fly it in NAV mode. It compares inbound track to database after the auto slew and loads frequencies. Avidyne does the same with DFC 90.

The biggest advantage integrated systems have is they show green and magenta needles so easy to see you are in the right HSI mode.

Right, also with the 430W and DFC90 you load the procedure from the database and get an information that the GPS overlay is for “information only”.

Peter I dont follow although we arent implicitly told the pilot presumably loaded the ils procedure on the 530 and the initial part of the procedure would have been flown using gps and the database would know the location of thd localiser.

There is no way of knowing, but this is highly unlikely. The symptoms point to the DCT mode to the NDB being used, and the report also says so.

The symptoms were compatible with the GPS distance to the NDB being used throughout the approach and to initiate the descent. If you load the procedure, the distance to the next waypoint is displayed, and it would be quite difficult to achieve the observed flight path.

Infact rereading the report carefully i dont quite follow what the pilot had in mind. It would seem he was using the d to function on the 530 to the dnd. That would have been using gps guidance. I assume he didnt then load the ils procedure or activate the procedure which would have warned of the use of gps guidance and automatically switched to using the ils transmitter but would have"known" the procedure was being flown hence my point about displaying the gps distance to the threshold while of course the pilot would also have been monitoring the dme. The suggestion is the pilot then flew the outbound using the compass radial supported by the gps in some way, but if the procedure hadnt been loaded as appears to be the case perhaps the gps was still in map mode. The suggestion then seems to be he was monitoring the distance to the dme in error thinking it was the dnd. He had selected the ils frequency but unfortunately never changed to using the ils frequency by mistake. The suggestion is he was flying the inbound ils course in some way and i guess again using only a heading. Of course the g/s never came alive and believing he was at the correct distance from the threshold (whereas it was the distance from the dme) commenced his descent presumably using the knee plate for guidance and assuming it was a localiser only approach. Given his experience it seems odd he didnt question the lack of g/s given he had been so cleared?

However all in all my point was that had a procedure been selected at any time, and it seems it wasnt, a 430 will sequence through the steps but shows distances to each step, whereas it also “knows” the distance to the threshold but this isnt display until the faf is reached.

Cobalt you are of course correct after completing the base turn it looks like direct to the ndb was selected in error thinking direct to the dnd had been selected. Had direct to dnd been selected this would have taken the aircraft to the threshold on the correct path assuming the base turn was completed accurately but of course without any form of vertical guidance other than initiating the g/s from the paper plate.

It almost suggests a pilot familiar with the basic functions of the 530 or wanting to use only that functionality for some reason.

Not quite true Peter. On something like a G1000 an ILS is loaded the same way as a GPS approach. And you fly it in NAV mode. It compares inbound track to database after the auto slew and loads frequencies. Avidyne does the same with DFC 90.

Right, also with the 430W and DFC90 you load the procedure from the database and get an information that the GPS overlay is for “information only”.

Did the accident aircraft have a G1000, 430W or a DFC90?

If not, I struggle to see the relevance. I am sure the Honeywell FMS on a 737 does it differently too.

It almost suggests a pilot familiar with the basic functions of the 530 or wanting to use only that functionality for some reason

Plus, many pilots don’t know about how this “VLOC” business works – see the multiple threads we have had on here, and reports of the auto switching not working for unknown reasons. Also some rightly do not trust this so they use a GPS in a very basic mode, especially when flying conventional approaches.

My KLN94 has “overlays” for ILS approaches too, but the relevance is zero.