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Lessons Learnt from
Uncommanded Marine Marker
Activation – A Case StudyLCDR 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
0
5
10
15
20
25
0 50 100 150 200
Per
cen
tage
of
Ga
s
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 of Locker
UncommandedInitiation 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
References1. 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
of 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