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ASN Wikibase Occurrence # 167092
Last updated: 25 December 2019
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Date:20-JUN-2014
Time:08:48 LT
Type:Silhouette image of generic R22 model; specific model in this crash may look slightly different
Robinson R22 Beta II
Owner/operator:LPS Aerial Work & Services Ltd
Registration: OK-LPS
C/n / msn: 3457
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: Substantial
Location:Hlavenec in the district of Prague-East, near the R-10 highway -   Czech Republic
Phase: En route
Nature:Private
Departure airport:Roudnice (LKRO)
Destination airport:Skuteč (LKSK)
Investigating agency: UZPLN
Narrative:
The pilot of the helicopter and the person sitting on the left seat provided the following information about the history of the flight.

Having arrived at the aerodrome, the pilot of the helicopter carried out pre-flight preparation during which he was focusing on information about the current weather condition and activation of areas on the route of the planned flight.

The pre-flight preparation was performed by a technical engineer, employee of the operator. The pilot completed pre-flight preparation of the helicopter and together with another person embarked the cabin. The pilot executed pre-start engine checks and after starting he carried out an engine check followed by the mandatory pre-take-off checks. All was in compliance with the flight manual and all the systems were free of defects.

The helicopter took off at 06:32 UTC (08:32 local time) in the direction of RWY 13 at LKRO and continued in the VFR flight directly to LKSK. The flight was proceeding in a standard manner, however, approximately 16 minutes after take-off a strong bang was heard from the engine compartment while the helicopter was overflying the north-west edge of the village of Hlavenec. The acoustic and light signal started indicating low RPM of the main rotor. At the same moment the rotations of the main rotor and the engine dropped to 90 per cent. Both of the said facts were not accompanied by the characteristic turning of the nose of the helicopter.

The pilot responded to the situation by a forceful lowering of the collective pitch control with the aim to bring the helicopter flight regime into autorotation. At the same time, he was pulling the cyclic pitch control in order to increase the critical RPM of the main rotor. The main rotor RPM were increasing only gradually and the helicopter continued descending while still in the autorotation mode of the main rotor. While continuously descending, the pilot was negotiating the trajectory in order to avoid the village and forest. In the altitude of approx. 3 metres above the place of landing, an abrupt loss of altitude and subsequent rough landing occurred. The vertical descent moderation before the landing had not been achieved even after forceful pull of the collective pitch control.

After the forced landing, the pilot shut the engine down, called for help by telephone and notified the authorities of an air accident. With regard to the spinal injury caused by the rough landing the pilot together with the other person on board remained seated in their seats, and, in this position, waited for arrival of the FRS and the ERS.

Causes: The cause of the air accident was the gradual destruction of both the driving double V-belts in the powering system of the main rotor. Thus caused operational failure of the drive system influenced the RPM of the main rotor in a negative way not only in the transition into the auto-rotation mode of the helicopter, but primarily in the landing stage in the auto-rotation mode.

Sources:

1. http://helihub.com/2014/06/20/20-jun-14-ok-lps-robinson-r22-prague-czech-republic/
2. http://www.uzpln.cz/pdf/incident_2mvydBBu.pdf
3. http://radio.cz/en/section/news/helicopter-crash-lands-in-field-outside-prague
4. http://tn.nova.cz/clanek/zpravy/domaci/u-obce-hlavenec-rano-spadl-vrtulnik-dve-osoby-jsou-zranene.html
5. http://helidat.cz/vrtulnik.php?ID=115_

Accident investigation:
cover
  
Investigating agency: UZPLN
Status: Investigation completed
Duration:
Download report: Final report


Revision history:

Date/timeContributorUpdates
20-Jun-2014 12:25 gerard57 Added
20-Jun-2014 12:31 harro Updated [Aircraft type, Registration, Cn, Source]
20-Jun-2014 14:02 Anon. Updated [Narrative]
06-May-2015 18:18 harro Updated [Departure airport, Destination airport, Source, Damage, Narrative]
16-Oct-2016 17:58 Dr.John Smith Updated [Operator, Location, Source, Narrative]
24-Apr-2018 18:31 harro Updated [Time]
18-Aug-2018 20:43 Dr.John Smith Updated [Source, Narrative]
18-Aug-2018 20:44 Dr.John Smith Updated [Narrative]
18-Aug-2018 20:45 Dr.John Smith Updated [Narrative]

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