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ASN Wikibase Occurrence # 180752
Last updated: 17 September 2021
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Type:Silhouette image of generic B609 model; specific model in this crash may look slightly different
AgustaWestland AW609
Registration: N609AG
MSN: 60002
Fatalities:Fatalities: 2 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:near Santhià, Vercelli -   Italy
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Departure airport:Cascina Costa
Destination airport:Cascina Costa
Investigating agency: ANSV
AW609 twin-engined tiltrotor prototype number 2 crashed and burst into flames near Santhià, Italy during high speed trials. Both occupants, one Italian and one US test pilot, died in the crash.

Flightradar24 tracking data shows N609AG operating in the area of Santhià at the time of the accident. Last recorded data by Flightradar24 show the aircraft at 4349 feet at 09:43 hours UTC.

ANSV says the crew commenced the third high speed dive with a 180° left turn, aiming for a speed of 293 knots. On roll-out they observed “slight lateral-direction oscillations”. The crew believed they were “self-damping”. The Pilot Flying attempted to correct the roll with “counterphase input roll manoeuvres and then pedal inputs” as they grew in amplitude and frequency. "However these actions did not dampen the oscillations, which instead became divergent, bringing the sideslip angle to reach values above the maximum allowed in those speed conditions". The flight control laws had the unintended effect of amplifying the oscillations and the sideslip reached 10.5° (6.5° greater than the limit) in just a few seconds. The investigators have “reasonable certainty” that the in-flight break-up was caused by “multiple contacts of the proprotors with the aircraft wings”, says ANSV. This, in turn, severed fuel and hydraulic lines in the leading edge of the wings, triggering a fire.


Accident investigation:
Investigating agency: ANSV
Status: Investigation completed
Download report: Final report
Safety recommendations:

Safety recommendation ANSV-10/3173-15/2/A/16 issued by ANSV to FAA, EASA
Safety recommendation ANSV-11/3173-15/3/A/16 issued by ANSV to ICAO
Safety recommendation ANSV-9/3173-15/1/A/16 issued by ANSV to FAA, EASA


Photo of N609AG courtesy

Yeovilton (EGDY / YEO)
11 July 2015; (c) Phil

Revision history:

30-Oct-2015 11:34 gerard57 Added
30-Oct-2015 11:41 harro Updated [Operator, Source, Narrative]
30-Oct-2015 11:43 harro Updated [Location, Departure airport, Narrative]
30-Oct-2015 11:57 harro Updated [Registration, Cn, Nature, Departure airport, Source, Narrative]
30-Oct-2015 11:58 harro Updated [Cn]
30-Oct-2015 13:03 MKAP Updated [Source]
30-Oct-2015 13:03 Iceman 29 Updated [Photo, ]
30-Oct-2015 13:25 Anon. Updated [Source]
30-Oct-2015 13:31 aegir Updated [Time, Departure airport, Source]
30-Oct-2015 13:45 rotorspot Updated [Source, Narrative]
30-Oct-2015 16:58 Iceman 29 Updated [Embed code]
30-Oct-2015 17:20 Anon. Updated [Source]
30-Oct-2015 17:56 Aerossurance Updated [Time, Destination airport, Narrative]
30-Dec-2015 16:13 Aerossurance Updated [Source, Narrative]
05-Mar-2016 10:22 Aerossurance Updated [Source]
24-Jun-2016 14:59 Aerossurance Updated [Source, Narrative]
24-Jun-2016 18:38 Aerossurance Updated [Source]
24-Jun-2016 18:38 Aerossurance Updated [Phase, Narrative]
21-Dec-2016 19:30 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
11-May-2017 11:31 Aerossurance Updated [Source, Narrative]

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