Piper Arrow G-BVDH down on the Simplon Pass in Switzerland

@cosy,

why don’t you recreate your post here in English? I think it is worth it.

The final report has been published.

The conclusion as follows:

The accident, in which the pilot lost control of the aircraft at low altitude and collided
with the ground, was due to a lack of anticipation in the management of the flight
climb, which caused the stall.

A lack of training and experience in mountain flying contributed to the accident.

The investigation was unable to determine why the pilot flew into the Simplon Val-
ley at an altitude of 2200 ft below that recommended on the ICAO 1:500 000 map

The SUST does a good job in reconstructing the flight path and provides graphical representations of the flight as well as images. The report is well worth the read.

https://www.sust.admin.ch/inhalte/AV-berichte/G-BVDH_SB_e.pdf

boscomantico wrote:

A poor translation from French?

Yes, that is exactly what it is. Please also note that the French version of this report constitutes the original and is therefore binding. So the English version is a translation.

Peter wrote:

They do get the meaning across. Such an avoidable accident!

Well, if you do read the accident report fully, they do a pretty thorough job analyzing what happened. It is pretty clear, and interestingly enough, pretty much what we discussed quite early on once we saw the FR track.

Peter wrote:

Put more simply: He turned into the canyon too early. He should have climbed another ~2000ft before turning into it.

Or he started his climb too late. There was no reason to fly so low in the valley nor to climb so slow.

The report gives a pretty good analysis on page 20 of the report:

Final Report G-BVDH
The choice of the path and its lateral adjustment demonstrate that the lateral planning performed by the pilot was
appropriate for the intended flight.

However, for some undetermined reason the pilot never planned a flight altitude,
as it remained unchanged at an altitude of 15,900 ft throughout the flight.

The introduction of a cruise altitude appropriate for the flight also allows visualisation of
a potential collision with terrain using the Skydemon application (see Figure 14)
during flight planning. The picture in Figure 3, taken in flight by the backseat
passenger, shows that the “Colour high terrain” functionality was not activated, and
therefore the visualisation of a risk of collision was not available in flight either.

From Montreux (waypoint N°1 in Figure 2) to Brig (waypoint N°6) the lateral
trajectory of the G-BVDH aircraft indicates that the pilot followed precisely his pre-
programmed path on his electronic tablet. His ground speed remained stable at
about 120 kt and the rate of climb was only about 100 ft/min as shown in Figure 3.
These flight parameters brought him after 20 minutes of flight from Martigny to an
altitude of 6100 ft AMSL at the entrance of the Simplon Valley, about 2200 ft below
the minimum safe altitude recommended on the ICAO chart.

This lack of anticipation on the management of the flight altitude, generated a climb
with a pronounced nose-up attitude in the Simplon valley during the last 5 NM
which corresponds to a flight duration of approximately 2 min 30 sec. With the
configuration of the dashboard of a PA28, this nose-up attitude consequently also
increased the difficulty to see the ground on its trajectory. This lack of visibility led
him to fly low over the Simplon Valley power line and prevented him from
anticipating a possible turn around to adapt his flight tactics.

Once he reached the Simplon Pass, he induced a right turn to follow the natural
path of the valley. At this point the critical angle of attack was exceeded and the
left wing stalled. The aircraft crashed into the scree on the north-west flank of the
Hübschhorn without the pilot being able to recover the aircraft due to a lack of
height.

So there are lots of holes in the Swiss Cheese:

- The cruise altitude he entered into SkyDeamon was never attained nor realistic.
- The terrain warning system of SkyDeamon was de-activated. It would have shown him clearly he was too low.
- He followed his pre-determined flight path on the tablett rather than visually following the valley. This put him onto the LEFT side of the valley, which is against established practice of flying on the Right side of the valley. (If the fact that he was English has something to do with that has to remain open, but it may well have been a factor, after all in the UK “driving” on the Left is the norm. For anyone else flying on the Left side of a valley might trigger subconcious cautions.) Had he followed the valley like it is usually done, he would have stayed onthe right hand side of the valley.
- The view out of the cockpit at the high angle of attack to the front was inadequate.

I would also add that his wife was said to have had a PPL, but she was sitting in the back from where her view of the trajectory was even worse.

Unfortunately, such grave errors in the Alps are often fatal. The SUST rightly concludes that insufficient knowledge of mountain flying skills most definitly have contributed to this accident. Also with this airplane it should have been easily possible to attain the needed altitude, had the climb been steeper throughout the Valais.