The Downwind Turn Revisited

In 2018, a Junkers Ju 52 crashed in the Swiss Alps while attempting to cross a 10,000-foot saddle from south to north amid gusting winds.

Peter Garrison

Monday, November 05, 2018 at 11:39 PM ET

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The fatal August crash of a Junkers Ju 52 brings to mind some aspects of downwind turns that are worth discussing. JU-Air

Key Takeaways:

The 2018 Ju 52 crash in the Swiss Alps, which occurred while attempting a pass in strong, gusty winds, highlights the potential dangers of aviation in challenging mountainous conditions.
The article debunks the common misconception that turning downwind inherently causes an airplane to lose airspeed and stall, clarifying that airspeed is relative to the air mass, not the ground.
Instead, the primary hazard lies in strong gusts, particularly those with a vertical component relative to the aircraft in a banked turn, which can rapidly increase the angle of attack and induce a stall, especially when operating with a reduced stall margin.

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In August 2018, a sightseeing flight crashed in the Swiss Alps, killing all 20 aboard. The airplane, a Junkers Ju 52, was attempting to cross a 10,000-foot saddle from south to north. The wind was out of the north, gusting to 25 knots. Witnesses said the airplane approached the saddle, then banked sharply to the left and suddenly dived to the ground, “as if following a plumb line.”

The official analysis of the accident will not emerge for some time. I don’t have an opinion as to what actually caused it. But the accident did bring to mind some aspects of downwind turns that are worth discussing.