Lessons Learnt from Uncommanded Marine Marker Activation A Case - - PowerPoint PPT Presentation

Lessons Learnt from Uncommanded Marine Marker Activation – A Case Study

LCDR James Robertson Technical Staff Officer - Navy Directorate Ordnance Safety

Scope

• Incident
• Summary of Mk58 design
• Cause of incident
• Contributing factors
• Remediation activities
• Lessons learnt

Incident

12 Jan 19 – A Mk58 Marker Location Marine (MLM) experienced an uncommanded initiation on Australian Warship HMAS Warramunga while berthed at Fleet Base East, Sydney 550 mm

Summary of Mk58 Design - Employment

• Marking location at sea (by ships and aircraft)
• Emergency Low Visibility Approach by aircraft to ships

Summary of Mk58 Design - Activation

• Ring pull removed – exposes sea-water activated battery
• Launched in to sea – battery activates

Summary of Mk58 Design – Operation

• Battery activates squib which ignites starter composition
• The first red phosphorous candle ignites
• As first candle burns out, second candle ignited by time fuze

Cause of Incident

• Ingress of saltwater in to battery cavity
• Contributing factors

– Inappropriate venting procedure – Exposure to saltwater due to external cooling of pyrotechnics lockers

Contributing Factors – Lifing Changes

Australian Life = 15 years Shelf Life: Three (3) Years Service Life: One (1) Year

Contributing Factors - Venting

• Australia added requirement for venting
• No evidence found of when or why requirement added
• Likely due to concerns regarding gas evolution over long life
• OEM does not recommend venting

Contributing Factors – S3 Assessment

5 10 15 20 25 50 100 150 200

Percentage of Gas Days

O2 and CO2 Gas Levels in Mk58 Composition Over 6 Months

CO2 O2

[1] M Ringwald, ‘Red Phosphorus Gas Generation Study’, NSWC, 04 August 1991 [1]

Contributing Factors - Maintenance

Extract from Australian “Explosive Ordnance/Weapons Preparation Manual”

Summary of Contributing Factors

Long, non-OEM Life due to Poor S3 Processes Non essential venting of Mk58 due to Poor S3 Processes Mk58 Battery Cavity Punctured due to Poorly Implemented Venting procedures Seawater Cooling of stowage locker due to High Temperatures Seawater ingress to Mk58 battery due to Poor Watertight Integrity

• f Locker

Uncommanded Initiation of Mk58

Safety Case Management

• Explosive Ordnance Design Assessment (EODA) - 2011
• Conducted to rectify previous “Grandfathering” of Mk58
• Accepted many of the previously unsubstantiated

decisions on issues such as lifing and venting

• Supplementary EODA – 2013
• Prompted by integration of item on to new platforms
• Still did not address many of the issues in original EODA

Safety Case Management – Failure Mode

• Review of incidents conducted (2011 – Present)
• 29 Incidents where items failed to function on correct deployment

– Well within required 90% Operational Level of Reliability

• 25 Reported Unexploded Ordnance Incidents involving Mk 58

– Self-scuttling of item relies on item filling with water after candles are expended – When item fails to function, tends to float due to not filling with water – Item does not fail-safe – Tend to wash up on beach, majority on civilian beaches

Remediation Activities

• All stakeholders

– The practice of venting Mk58 has been ceased – All user units have returned vented items – All vented items at depots segregated and will be disposed of

• Acquisition and Sustainment Agency

– Audit of all documentation remove requirement for venting – Reduce service life to 7 years based on 848 similar items in storage with no evidence of bulging – In Service Surveillance Program to gather quantitative evidence to support this lifing – Rebuilding of the Safety Case using evidence – 12 month operational life in maritime environments

Lessons Learned

• A lack of past incidents doesn’t equate to an absence of safety

concerns

• Must be vigilant and systematic in reviewing past safety cases to

identify potential risks

• When updating/maintaining Safety Cases don’t assume previous

assessments meet contemporary standards

• S3 and Engineering assessments should be based on primary

source evidence whenever possible

• Maintenance requirements should be identified through rigorous

engineering analysis

• Lifing needs to be evidence based
• In Service Surveillance is a key tool in maintaining the validity of

safety cases

References

• 1. Explosive Ordnance Design Assessment 1 Marker Location Marine

Mk 58 Mod of 22 Jul 11

• 2. Supplementary Explosive Ordnance Design Assessment Marker

Location Marine Mk 58 Mod 1 of 12 Aug 13

• 3. QPL-CWEO-5021-113

Certification Delta Assessment Marker Location Marine Mk 58 Mod 1 v1.0 of 14 Mar 13

• 4. Meeting Minutes KC-58 EOSM and System Safety Working Group
• f 23 May 19
• 5. Kilgore Flares KC-58 Marine Location Marker Brochure
• 6. Red Phosphorus Gas Generation Study, Mike Ringwald of 08 Apr 91
• 7. Email Werner Sperber / (FLTLT O’Brien, Troy Smith) of 14 Mar 19
• 8. DEOP Topic -32 Marker Location Marine Mk 58 Mod EO/Weapons

Prep Manual 1 Issue 1

• 9. Explosive Ordnance Safety Message 1900014 – Marker Location

Marine Mk 58 Mod 1 of 24 May 19 10.DEOP Topic -26 Marker Location Marine Mk 58 Mod 1 Design Limit Summary Issue 1 11.Technical Investigation Uncommanded Initiation of MK58 Mod 1 Marker Location Marine of 09 Sep 19

Questions

Extra Notes