Leicester Helicopter Crash AAIB interim report targets loss of yaw (turning) controls and broken linkages to tail rotor

This is an informal precis of an AAIB investigation interim report into the Leicester helicopter crash. 

Julian Bray the aviation expert and broadcaster suggested on BBC Wales earlier today that the initial findings appear to clear the pilot, as the report strongly suggests, a left yaw [turn] foot pedal control actually pitched the helicopter uncontrollably into a maximum right yaw, spiralling the helicopter nose first onto stepped concrete.

Multiple linked mechanical failures and a control rod effectively unscrewing itself in the process added to the complex process. The investigation is being aided by the recovery of the combined voice and data recorder by the AAIB team fitted to this Augusta AW169, and decoded at AAIB Farnborough.  
  
Aircraft Type and Registration: Agusta AW169, G-VSKP
No & Type of Engines: 2 Pratt & Whitney Canada PW210A turboshaft engines
Year of Manufacture: 2016 (Serial no: 69018)
Location King Power Stadium, Leicester
Date & Time (UTC): 27 October 2018 at 1937 hrs
Type of Flight: Private
Persons on Board: Crew - 1 Passengers - 4
Injuries: Crew - 1 (Fatal) Passengers - 4 (Fatal)
Nature of Damage: Aircraft destroyed
Commander’s Licence: Airline Transport Pilot’s Licence (A and H)
Commander’s Age: 53 years
Commander’s Flying Experience: TBA
Last 90 days - 40 hours Last 28 days - 7 hours

Information Source: AAIB Field Investigation


The investigation
  
The accident occurred at 19371 hours on 27 October 2018. The AAIB published Special Bulletin S1/2018 on 14 November 2018 to provide preliminary information gathered from the site investigation, subsequent technical investigation, recorded data, and other sources.

This second Special Bulletin provides information on the findings to date of a detailed examination of the helicopter’s yaw control system.



The tail rotor control system was first inspected at the crash site. This identified that the input lever mechanism was not attached to the control shaft. The pin, spacers and one of the locating bearings were missing from the lever. The locking nut and pin carrier were found loose in the tail rotor fairing and were bonded together (they should be separate components). The threads of the nut appeared to be undamaged. There was no evidence of the split pin, and the control shaft threaded section had moved inside the outer shaft and was no longer visible.
The control shaft, the locking nut and pin carrier, and the duplex bearing/sliding unit assembly were removed from the wreckage and inspected in detail. The locking nut on  the bearing end of the control shaft was found to have a torque load significantly higher than the required assembly value. The inner races of the bearing could only be rotated a few degrees in either direction by hand. There was a build-up of black grease inside the slider unit around the inboard face of the duplex bearing. The section of the control shaft adjacent to this bearing face showed evidence of burnt-on grease and was discoloured along its length.

The components were then inspected using a Computed Tomography (CT) Scanner. This uses x-rays to image the inside of the components, then recreates them as a 3-D model.

The results showed that the nut and pin carrier were friction welded together. The threaded portion of the control shaft, at the actuator end, was inside the outer shaft and contained the remains of the split pin. The top and bottom of the split pin had been sheared off in rotation. The scan of the bearing showed fractures to the bearing cages and significant damage to the surface of the inner bearing races, the damage being worse on the inboard bearing race where there was also evidence of sub-surface damage. The scan also showed evidence of debris accumulating in the bearing raceways  The bearing was then removed from the sliding unit and disassembled, revealing evidence of relative rotation between the sliding unit and the bearing outer ring. The debris present on the CT scan was identified as a combination of black dust and metallic particles.


Failure sequence  


The evidence to date shows that the loss of control of the helicopter resulted from the tail rotor actuator control shaft, becoming disconnected from the actuator lever mechanism. Disconnection of the control shaft prevented the feedback
mechanism for the tail rotor actuator from operating and also the tail rotor actuator from  responding to yaw control inputs.
Loss of the feedback rendered the yaw stops ineffective, allowing the tail rotor actuator to continue changing the pitch of the tail rotor blades until they reached the physical limit of their travel. This resulted in an uncontrollable right [turn] yaw.
Sufficient force and torque had been applied to the castellated nut on the actuator end
of the control shaft to friction weld it to the pin carrier and to shear the installed split pin.
The observed condition of the duplex bearing and the increased torque load on the castellated nut that remained on the spider end of the shaft is consistent with rotation of the tail rotor actuator control shaft.
Whilst the shaft was rotating and a yaw control input was applied, the shaft “unscrewed” from the nut, disconnecting the shaft from the actuator lever mechanism, and causing the nut to become welded to the pin carrier.

Safety actions
On 5 November 2018 the manufacturer of the helicopter issued Alert Service Bulletin (ASB) 169-120 for AW169 helicopters, giving instructions for a

precautionary inspection of the tail rotor control assembly on all helicopters in
the global fleet. On 6 November the manufacturer also issued ASB 189-213
for AW189 helicopters, which have a similar tail rotor control system.
AAIB investigations are conducted in accordance with Annex 13 to the ICAO Convention on International Civil Aviation,
EU Regulation No 996/2010 and The Civil Aviation (Investigation of Air Accidents and Incidents) Regulations 2018.


The sole objective of the investigation of an accident or incident under these Regulations is the prevention of future accidents and incidents. It is not the purpose of such an investigation to apportion blame or liability.


Accordingly, it is inappropriate that AAIB reports should be used to assign fault or blame or determine liability, since neither the investigation nor the reporting process has been undertaken for that purpose.

The European Aviation Safety Agency (EASA), in its capacity as the regulator
responsible for the type design approval of the AW169 and AW189, issued
Airworthiness Directive 2018-0241-E dated 7 November 2018 to mandate
these inspections.

https://www.gov.uk/government/news/update-on-leicester-helicopter-accident-g-vskp?utm_source=9dabe4fe-6523-4a70-b57e-83d1017a08c0&utm_medium=email&utm_campaign=govuk-notifications&utm_content=immediate

On 19 November 2018 the EASA issued AD 2018-0250-E, superseding
AD 2018-0241-E, to require a precautionary one-time inspection of the tail
rotor duplex bearing and, depending on findings, applicable corrective actions. On 21 November 2018 the helicopter manufacturer published Emergency Alert Service Bulletin ASB169-125 for AW169 helicopters, and ASB189-214
for AW189 helicopters, giving further instructions for a one-time inspection
of the tail rotor duplex bearing. The EASA issued AD 2018-0252-E on
21 November 2018, superseding AD 2018-0250-E and mandating this
inspection.

On 30 November 2018 the helicopter manufacturer published Emergency Alert Service Bulletin ASB 169-126 for AW169 helicopters, and ASB 189-217
for AW189 helicopters, introducing repetitive inspections of the castellated nut
that secures the tail rotor actuator control shaft to the actuator lever mechanism,
and the tail rotor duplex bearing. The EASA issued AD 2018‑0261‑E on
30 November 2018 mandating the repetitive inspections.

Ongoing investigation

  

The initiating cause and exact sequence of the failure that resulted in the loss of tail rotor control is being investigated as a priority. Work continues to identify the cause of the image observed to the duplex bearing and to establish its contribution to the failure

sequence. The AAIB is working with relevant organisations to identify any other factor that may have contributed to the loss of tail rotor control.

The other areas of investigation specified in Special Bulletin S1/2018 will continue, and the AAIB will report any significant developments as the investigation progresses. 


@JULIANBRAY +44(0)1733 345581, Journalist & Broadcaster, Aviation Security & Airline Operations Analyst/expert,  ... http://feeds.feedburner.com/BraysDuckhouseBlogwww.aviationcomment.com,  ... http://www.freelancedirectory.org/user.php?user=8121  ... www.freelancedirectory.org?name=Julian.Bray.aviation.comment , ... Aviation / Travel / Maritime & Cruise Industries, NUJ, EQUITY, LIVE ISDN LINK, Broadcast ISDN COOBE ++44 (0)1733 345020 ... SKYPE: JULIAN.BRAY.UK e&oe Old faithful NOKIA: 07944 217476
Post a Comment

BREAKING NEWS

Air Accidents Investigation Branch: current field investigations - GOV.UK

https://www.gov.uk/government/publications/aaib-current-field-investigations/air-accidents-investigation-branch-current-field-investigation...

Search JULIAN BRAY AVIATION SECURITY BLOG

URL COMPACTOR

AVIATION SECURITY BLOG: Key in your long URL to make tiny:

JULIAN BRAY ++44(0)1733 345581 BROADCAST ISDN ++44(0)1733 345 020 all codecs

MOBILE: 07944 217476

AVIATION SECURITY EXPERT, AIRLINE OPERATIONS & NATIONAL SECURITY ISSUES.

BROADCASTER, COLUMNIST & JOURNALIST. NUJ & FULL EQUITY MEMBER.

IMMEDIATE LIVE BROADCASTING VIA OWN ISDN COOBE, STUDIO & HIGH SPEED BROADBAND SKYPE

ISDN +44 (0) 1733 345020.

OFFICE +44 (0) 1733 345581

http://www.journalistdirectory.com/journalist/XLgEm/Julian-Bray




AVIATION & CRUISE, MARTIME INCIDENTS, SAFETY ISSUES, TRAVEL THREATS & PERILS, TERRORISM ISSUES, WORLD TRAVEL & INSURANCE COVER ISSUES, CONFLICT ZONES, LONDON RUNWAY, FEATURES & CORRESPONDENT RESEARCH PACKAGES. NATIONAL & LOCAL POLITICS, LAW & ORDER, LITIGATION SUPPORT.

"Adept at holding national and international politicians and business people to account, has a 'Marmite' but considered approach to politics and always well prepared" Iain Wilson

Julian Bray broadcasts and comments via ISDN +44 (0)1733 345020 (GLENSOUND C5 Dual Codec), VoIP and SKYPE >>> JULIAN.BRAY.UK <<< mobile 07944 217 476

BBC Contributor 10476453

LANDLINE number in the UK is +44(0) 1733 345581 Use this number to pre-brief or to book link.

TELEVSION AND RADIO LIVE INTERVIEWS AND CONTRIBUTIONS

RECENT FEEDS:

RUSSIA METROJET, GERMANWINGS, MH17 INCIDENTS and other RECENT TV NEWS & RADIO AUDIO FEEDS

LASER PENS BBC NEWS

Amelia Erhart Mystery BBC Wales

http://www.bbc.co.uk/programmes/b08rg0nx

Julian Bray Radio Podcasts

http://talkradio.co.uk/julian-bray

https://www.youtube.com/watch?v=weCHZDsnpEI

https://audioboom.com/boos/5133360-easyjet-results-with-aviation-expert-julian-bray

https://www.rt.com/op-edge/360687-military-intel-mh17-include/ September 2016

#BorisJohnson 'right for all the wrong reasons' to dismiss Heathrow, says @JULIANBRAY - bit.ly/2cunT2Z pic.twitter.com/Jw3PwFOasm

http://www.abc.net.au/radionational/programs/breakfast/russian-airline-rules-out-mechanical-failure-or/6907142

https://soundcloud.com/rttv/bray-7k9268?utm_source=soundcloud&utm_campaign=wtshare&utm_medium=Facebook&utm_content=https%3A%2F%2Fsoundcloud.com%2Frttv%2Fbray-7k9268

http://www.pri.org/stories/2012-01-16/why-modern-navigational-technology-didnt-prevent-costa-concordia-accident

https://twitter.com/VictoriaLIVE/status/661125924432146432

http://rinf.com/alt-news/tag/julian-bray/

http://www.marketplace.org/2012/01/16/business/cruise-ship-industry-impacted-disaster

http://www.pri.org/stories/2012-01-16/why-modern-navigational-technology-didnt-prevent-costa-concordia-accident

https://www.youtube.com/watch?v=yiKsLJxc6WA

https://soundcloud.com/julian-charles-braybray

https://soundcloud.com/julian-charles-bray

https://youtu.be/yiKsLJxc6WA?t=1m12s

http://edition.cnn.com/videos/world/2015/03/24/idesk-bray-intv-germanwings-descent.cnn

https://soundcloud.com/rttv/airbus-co-pilot

http://www.itnsource.com/shotlist//ITN/2012/03/05/T05031202/http://www.itnsource.com/en/shotlist/ITN/2010/11/04/T04111005/#videoPopUpDiv

https://audioboom.com/boos/3579946-why-has-the-low-cost-airline-industry-been-thriving-morningmoney

http://talkradio.co.uk/news/airport-expansion-boris-johnson-right-all-wrong-reasons-dismiss-heathrow-1609164227

http://www.msn.com/en-us/news/royalbaby/russian-passenger-jet-crashes-in-central-sinai/vp-BBmEGu9

http://edition.cnn.com/videos/world/2015/10/31/russian-passenger-jet-plane-crashed.cnn

https://audioboom.com/boos/3289201-billybambrough-brings-us-the-latest-from-the-paris-air-show-morningmoney

http://edition.cnn.com/TRANSCRIPTS/1510/31/cnr.22.html

https://soundcloud.com/rttv/bray-7k9268?utm_source=soundcloud&utm_campaign=wtshare&utm_medium=Facebook&utm_content=https%3A%2F%2Fsoundcloud.com%2Frttv%2Fbray-7k9268

https://www.rt.com/op-edge/323287-su24-fighter-russia-turkey-syria/ Scroll down final VT

https://audioboom.com/boos/3918847-a-new-aviation-strategy-julianbray-oliver__clark-talk-on-the-europeancommission-s-airline-announcement

https://audioboom.com/boos/3933313-julianbray-talks-on-the-airport-expansion-delay-the-heathrow-bid-is-frankly-illegal

https://audioboom.com/boos/4241311-a-closer-look-at-the-deal-to-buy-london-cityairport-with-aerospace-specialist-julianbray


http://www.cbc.ca/i/caffeine/syndicate/?mediaId=2685621754 AIR DUBAI CRASH MARCH 2016 Television 2-way with CBC Canada via 'upmarket' SKYPE

https://ca.news.yahoo.com/video/plane-circled-airport-bad-weather-110053170.html AIR DUBAI CRASH 19/03/2016 Julian Bray first reaction

https://audioboom.com/boos/4368310-is-the-aerospace-sector-in-trouble-julian-bray-discusses-as-boeing-plans-to-cut-thousands-of-jobs

Julian Bray Broadcaster Radio Podcasts Selection



EGYPTAIR UPDATES

CargoLogic Air load one of their mega all cargo aircraft. In addition to purpose built frighters, many end of first lease, state-of-the-art wide-bodied passenger aircraft are currently being snapped up and rapidly re-purposed for all cargo operation. As the 21st Century trend is away from airport hub/spoke operation - apparently Heathrow [LHR] is yet to get the memo… -and towards single aisle narrow bodied passenger/cargo hold aircraft, working point to point schedules continues apace ...

JULIAN BRAY ++44(0)1733 345581

Illustrated Convention Lectures & Workshops, Keynotes, Broadcast Briefings, Media Presentational Training, Aviation Security and Operations Incident Management Consultancy

http://www.freelancedirectory.org/?name=Julian.Bray.aviation.comment

(ISDN BROADCAST LINK ++44(0)1733 345 020) all codecs G.722 & ATX Developed for use in ISDN remote broadcasting, G.722 is the original wideband speech codec to be standardized by the ITU-T. By sampling the speech signal at 16 kHz, G.722 more than doubles the encoded speech information, providing richer sound and better clarity than narrowband speech codecs. ( (ISDN2 BT BOX INSTALLED AT HOME: LIVE LINKS AVAILABLE AROUND THE CLOCK )

Book slot on landline 01733 345581

Mob: 07944 217476 http://www.aviationcomment.com/ E&OE

http://www.freelancedirectory.org/?name=Julian.Bray.aviation.comment

COVERING TRANSPORTATION & ASSOCIATED POLITICAL ISSUES IN ALL FORMS plus RELATED INDUSTRIES including AEROSPACE, COMPUTER NETWORKS, RAIL, AVIATION, CRUISE, FERRIES, MERCHANT MARITIME, MILITARY, TRAVEL & HOLIDAY INDUSTRIES, CAA REPORTS, TERRORISM & SABOTAGE, COMPUTER MISUSE & SYSTEM FAILURES, TRAVEL AGENTS, ATOL ISSUES, CIVIL & COMMERCIAL AVIATION. AIRSHOW ORGANISATION & LOGISTICS.

Contact numbers 01733 345581 OR Trusty Nokia Mobile: 07944 217 476 OFFICE: 01733 345581 and answerphone email: julianbray@aol.com

BROADCAST ISDN2 LINE: 01733 345020 ISDN DIGITAL DIAL-UP only. [ BH VENDOR #10476453 add PE28xl ]

SKYPE: JULIAN.BRAY.UK (directly wired Ethernet connection on high speed Virginmedia cable) ALSO GLENSOUND ISDN GSGC5 ISDN LOCATION UNITS FOR PROFESSIONAL DRY HIRE

http://www.freelancedirectory.org/?name=Julian.Bray.aviation.comment

Julian Bray provides: Opinion, comment, forward thinking speculation, keynote presentations and workshops for corporate organisations on Travel, Cruise & Aviation: conflict zones, terrorist impact, cybercrime and DoS issues, drone (UAV) issues, safety (black boxes, emergencies), airline operations, aviation finance, political implications, and all forms of incident risk.

He operated at board level with several airline and aviation groups, including Alitalia, British Island Airways, British Airways, Galileo , British Aerospace, Skyways, former CEO City firm Leadenhall Assoc. (PR WEEK TOP 150) Founder CNS City News Service. Director NTN Television News (joint co. with ITV Wales TWW) Debretts People 2017 and featured in launch edition of the PRWeek Black Book. Investigative Journalist and Broadcaster.

After-dinner speaker and presenter. NUJ LIFE MEMBER & FULL EQUITY MEMBER.

Direct links to a selection of television and radio contributions can be found at foot of this page. Scroll down. Join the conversation here or on Twitter at @aviationcomment @julianbray.

A retweet, comment or other publication by any means does not constitute an endorsement. Quoted Content subject to creditline 'Julian Bray' . During career an active MCIPR, MMC & MBDS.

Main UK telephone and prime contact number 01733 345581.

Mob: 07944 217476

http://www.freelancedirectory.org/?name=Julian.Bray.aviation.comment

ISDN2 Loop Test (by arrangement) 01733 345020

Download the new CAA DRONECODE HERE : http://dronesafe.uk/wp-content/uploads/2016/11/Dronecode.pdf

Glensound GSGC5 ISDN LOCATION (COOBE - FLYAWAY) COMMENTARY UNITS/COLES LIP MICS FOR PROFESSIONAL HIRE

VIDEO PROJECTOR & SMALL FORMAT PUBLIC ADDRESS/ MUSIC PLAYOUT HIRE







BBC LOCAL NEWSROOMS

< script async src="//platform.twitter.com/widgets.js" charset="utf-8">

The Small Print...

TERMS & CONDITIONS

This is the small print, demanded by the legal eagles, we've tried to keep it clear and simple, this is in addition to, and not in the alternative to the NUJ Code of Professional Conduct.

Welcome to JULIAN BRAY AVIATION SECURITY BLOG. If you continue to browse and use this website you agree to comply with and be bound by the following terms and conditions of use, which together with our privacy policy govern our relationship with you regarding this website.

The term JULIAN BRAY AVIATION SECURITY BLOG or ‘us’ or ‘we’ refers to the owner of the website. The term ‘you’ refers to the user or viewer of our website. The use of this website is subject to the following terms of use, which may be varied at any time:

  • The content this website is for your general information and use only. It is subject to change without notice.
  • Neither we nor any third parties provide any warranty or guarantee as to the accuracy, timeliness, performance, completeness or suitability of the information and materials found or offered on this website for any particular purpose. You acknowledge that such information and materials may contain inaccuracies or errors, we expressly exclude liability for any such inaccuracies or errors to the fullest extent permitted by law.
  • Your use of any information or materials on this website is entirely at your own risk, for which we shall not be liable. It shall be your own responsibility to ensure that any products, services or information available through this website meet your specific requirements and you have made your own independent enquires as to the content..
  • This website contains material which is owned by or licensed to us. This material includes, but is not limited to, the design, layout, look, appearance and graphics. Reproduction is prohibited other than for review purposes, or where specific permission has been granted, for example in connection with a commission or contribution supported by a written contract and any terms in accordance with the copyright notice, which forms part of these terms and conditions.
  • All trademarks reproduced in this website, which are not the property of, or licensed to the operator, are acknowledged on the website.
  • Unauthorized use of this website may give rise to a claim for damages and/or be a criminal offence.
  • From time to time this website may also include links to other websites. These links are provided for your convenience to provide further information. They do not signify that we endorse the linked to website(s). We have no responsibility for the content of the linked website(s).
  • E&OE Errors and omissions excepted. Use of quoted content subject to creditline: Julian Bray, broadcaster.
  • Writers P.I. & P L I. # WRT001966