US Police Helicopter Night CFIT: Is Your Journey Really Necessary?
US Police Helicopter Night CFIT: Is Your Journey Really Necessary? On 27 March 2014, at 0147 local time, ex-military Bell OH-58A, N497E, operated by, the Kern County Sheriff’s Office (KCSO) collided with terrain near Tehachapi, California. The three occupants were uninjured, although the helicopter was substantially damaged. The Accident and Investigation The US National Transportation Safety Board (NTSB) say in their report that the flight commenced at 0121 to convey a police dog that had been shot in the leg three hours earlier the 87 miles to Lancaster for treatment as “the local veterinarian could not perform treatment due to the nature of the dog’s injuries”. The decision to task the helicopter was made at the “management level at the Incident Command Post” according to a statement by the Sheriff’s Office to the local press. The NTSB say the pilot (the chief flight instructor for the Air Support Unit [ASU]) had gone to sleep at 2130 for the three previous nights, and woken at 0530 on all but that day. He was on duty from 0800 to 1600 on both prior days. He was awakened that day by a phone call at 0015 calling him in for the flight and arrived at the ASU HQ in Bakersfield at 0100. He: …confirmed that visual meteorological conditions (VMC) prevailed at both the departure and arrival airports. He was aware that a weather front was moving through the area, and that he would most likely encounter instrument meteorological conditions (IMC) while en route. He planned to use Tehachapi airport, about 45 miles east of Bakersfield, as an alternate landing site should conditions deteriorate. At 0120, they loaded the dog into the rear left footwell, along with the K-9 Division Chief who was seated in the rear right seat. Both the pilot and the [Tactical Flight Officer] TFO were wearing Night Vision Goggles (NVG’s) throughout the flight. The departure was uneventful, but as they approached Tehachapi they encountered light rain, strong winds, and low clouds. The pilot decided to proceed, and wanted to see if Sand Canyon, east of Tehachapi, was passable. However, once they got beyond the lights of the city, he lost visual reference after flying into what he thought was clouds. He reported flying about 500 feet above ground level (agl) at that time, and was concerned that returning might cause them to collide with wind turbines and other obstacles in the area. The route was flanked by wind turbine-covered peaks. The pilot elected to slow the helicopter and initiate a gradual descent. However he wasn’t in cloud. The windshield had misted up due to a water leak. This limited the effectiveness of NVGs. During the descent, the TFO realized that the windshield had fogged up because he could still see out of the side window, and the pilot turned on the de-mister…and the TFO perceived that the helicopter was now performing gradual S-turns over the highway. He did not get the sense that they were descending… A few seconds later he [the TFO] looked out of the right window, and although he could not sense movement, they appeared to be rapidly descending. They transitioned over the eastbound lanes of the highway, and he immediately called for the pilot to pull up, however, a few seconds later the helicopter struck the ground…bounced back into the air, and rotated about 180 degrees. The...
read moreMetro 23 MLG Corrosion Causes Runway Excursion
Metro 23 MLG Corrosion Causes Runway Excursion On 20 February 2014 Fairchild SA227-DC Metro 23 (Metro IV) VH-UUB, was being operated on a charter flight from Avalon to Portland, Victoria by Sharp Airlines. Shortly after touch-down the aircraft veered off the runway at 75-80 knots. The 10 passengers and two crew were all uninjured. The Safety Investigation The Australian Transport Safety Bureau (ATSB) report that: The runway excursion resulted from failure of the lower torque link attachment lug on the left main landing gear’s yoke. This allowed the wheels to rotate through 90° with respect to the direction of aircraft travel and skid, producing a large braking effect on the left side. The Fracture The failure…resulted from pre-existing cracks that had progressively grown until the part had insufficient strength to support normal landing loads. The cracks initiated principally from areas of pitting corrosion in the lug’s bore and were propagated by cyclic stresses imposed during operation. The fractured [7075-T73 aluminium] yoke [manufactured by Klune Industries] contained four disused retaining pin holes (two each top and bottom) as a result of compliance with a service bulletin (SB) for installing a replacement [torque link shaft]TLS (CC7-32-012), released in 2002. The SB required drilling of a new pin hole in the lug to secure the replacement TLS and filling of the redundant holes with sealant. Sealing of the disused pin holes in this occurrence was not adequate as the sealant had either broken down over time or otherwise disbonded and come loose during service, providing additional entrance routes for moisture or other corrosives. Another entrance route was associated with wear on the yoke lug flanks where significant pitting was identified. Wear on the flanks and in the bore of the lug was sufficient to remove the protective anodic coating, which increased the susceptibility of the parts to corrosion. Corrosion pits act as stress concentrators and significantly reduce both the fatigue crack initiation life of the component as well as the crack initiation threshold stresses. Continued Airworthiness The Fairchild MLG yokes were maintained on condition and were not subject to any maximum service life restrictions. The aircraft was maintained using a 6-phase inspection program with an interval of 900 hours; this included a detailed inspection of the main landing gear at a phase 3 inspection (450 hours) and a routine inspection at a phase 6 inspection (900 hours). The most recent detailed (Phase 3) inspection was 436.5 hours prior to the occurrence, and a routine (Phase 6) inspection 37.3 hours prior to the occurrence. The operator advised that they performed a torque link freeplay inspection at the detailed inspection and if excessive freeplay was evident, then the components would be disassembled for further inspection. The ATSB report that a number of other similar lug failures in Australian and Canada. they say: With corrosion pitting being a precursor to the fatigue failure of the component, improvement of corrosion protection in the affected areas would further reduce the likelihood of this type of occurrence. ATSB Conclusions The runway excursion occurred as a result of fracture of the torque-link attachment lug on the aircraft’s left main landing gear yoke, which allowed those wheels to deviate from the normal direction of travel and cause asymmetrical braking forces that could not be countered by the flight crew. The torque link-to-yoke attachment lug fractured...
read moreSolent Hoegh Osaka Car Carrier Accident
Solent Hoegh Osaka Car Carrier Accident The Singapore registered 180m, 51,770 gross tonnage ‘pure car and truck carrier’ (PCTC) MV Hoegh Osaka, managed by Wallem Shipmanagement Pte Ltd, developed a significant starboard list when turning to port while departing Southampton on 3 January 2015. The Marine Accident Investigation Branch (MAIB) say in their recent report: As the list increased in excess of 40º, the ship lost steerage and propulsion, and subsequently drifted aground on Bramble Bank. A cargo shift as the ship listed resulted in a breach of the hull [caused by the tracks of a JCB excavator] and consequent flooding. Drone footage One crewman broke an arm and a leg after falling more than 18m as the vessel healed over. The MAIB explain that: All crew were safely evacuated from the ship and surrounding waters. There was no resulting pollution, and the ship was later successfully salvaged [by Svitzer Salvage under a Lloyd’s Open Form]. Stability modelling and analysis following the accident show that Hoegh Osaka listed heavily to starboard while turning around Bramble Bank as a result of having inadequate stability, which had not been identified prior to departure. The MAIB however have identified “that the practice of not calculating a departure stability condition on completion of cargo operations and before a ship sails extends…to the [pure car carrier] PCC/PCTC sector in general”. Why the Ship Listed In a statement to the media, Steve Clinch, the UK’s Chief Inspector of Marine Accidents stated: The MAIB’s investigation found that Hoegh Osaka’s stability did not meet the minimum international requirements for ships proceeding to sea. The cargo loading plan had not been adjusted for a change to the ship’s usual journey pattern and the number of vehicles due to be loaded according to the pre stowage plan was significantly different from than that of the final tally. The estimated weight of cargo was also less than the actual weight. Crucially, the assumed distribution of ballast on board, bore no resemblance to reality, which resulted in the ship leaving Southampton with a higher centre of gravity than normal. The Loading and Ballasting As is often the case in accidents, a late change in plan (due to New Year holidays) was critical in this accident. Southampton was originally to be the last of three port calls in NW Europe and stowage plans had been prepared on that basis. When the itinerary changed, the loading plans were not (though the ship was not bunkered with fuel, further reducing stability) . The cargo loaded in Southampton was loaded in the same location as it would have been had Southampton been the final loading port, not the first. In fact the MAIB state in their report: Although the chief officer advised the master that Hoegh Osaka’s GM [Metacentric Height] for departure was 1.46m and met the requirements of the loading and stability information manual, this advice was based on preliminary and, as it transpires, inaccurate figures. Given that the chief officer was re-entering the cargo figures into the loading computer as Hoegh Osaka was proceeding along Southampton Water, a thorough assessment of the ship’s stability had not been conducted prior to leaving the berth. Witness and anecdotal evidence suggests that this was a common practice and that final cargo figures were sometimes not received on board until after the ship had sailed....
read moreMarine Pilot Transfer Winching Accident
Marine Pilot Transfer Winching Accident (Brim Aviation AW109SP N361CR) During a night Marine Pilot Transfer (MPT) helicopter winching / hoist operation on 21 April 2014, the marine pilot being transferred, was injured. The marine pilot was being transferred from an outgoing ship to a container vessel, inbound to Astoria, Oregon, the 222 m, 27,437 gross ton MV Northern Vigor, by AgustaWestland AW109SP GrandNew N361CR operated by Brim Aviation under Part 133 (External Load Operations) for the Columbia River Bar Pilots. The fast flowing Columbia River divides Oregon from Washington State. The Columbia River Bar Pilots (CRBP) have been using a helicopter since 1996. Currently 70% of transfers, to ships typically 15nm out in the Pacific, are done using helicopters, the rest by pilot launch. The current AW109SP, radio call sign ‘Seahawk’, is flown with two pilots at night (one in daylight) and a winch operator for the single Goodrich hoist. The Accident Flight The marine pilot was lifted from the outbound vessel at 23:05 local and flown around 6 miles to the MV Northern Vigor. The US National Transportation Safety Board (NTSB) say in their report: Light rain and night meteorological conditions prevailed, and a company visual flight rules flight plan was filed for the flight. Per normal procedures, the helicopter’s crew planned to lower the ship [i.e. marine] pilot to the ship’s deck via a cable hoist while the ship was underway. When the helicopter arrived at the ship, dark night conditions prevailed, rain was falling, and the relative wind was blowing onto the starboard (right) bow of the ship. As explained in the CRBP’s report, the preference is normally to winch on to open hatch covers. However, the deck was almost completely covered by containers. The option of winching to the bridge wings was dismissed due to obstructions. The helicopter crew circled the ship to locate a suitable location to lower the ship pilot and settled upon a location close to the starboard bow. They identified that part of the starboard side of the Number 2 hatch was clear, albeit surrounded by containers, typically stacked two high (16ft). The ship pilot and the helicopter crew agreed that this was the best available location for the transfer. However, this location allowed the helicopter’s pilot to see and use only a very small portion of the ship as a visual reference for maintaining the helicopter’s position while lowering the ship pilot. The aircraft came into a hover at 20-25ft. The relative wind, the container locations, the right hand winch location and the risk of a tail rotor strike all made this choice demanding. There is no mention in the reports of the deck lighting. The Pilot Flying used the forward containers as a reference while the winch operator conned him into position. At 23:18: Just as the ship pilot made contact with the deck, the ship’s bow pitched down, and the helicopter pilot lost visual contact with the ship. Because the helicopter pilot was unable to see the ship, the helicopter began to move aft relative to the ship. The hoist operator was unable to release the hoist cable quickly enough to prevent pulling the ship pilot off the deck and had to cut the cable. The ship pilot fell a few feet to the deck… He recovered from the fall, and successfully piloted the ship thorough the Columbia River mouth to its destination. Upon...
read moreAAIB Report on 2013 Sumburgh Helicopter Accident (CHC Scotia AS332L2 G-WNSB)
AAIB Report on 2013 Sumburgh Helicopter Accident (CHC Scotia AS332L2 G-WNSB) The UK Air Accidents Investigation Branch (AAIB) has published its report into the 23 August 2013 accident were CHC Scotia Airbus Helicopters AS332L2 Super Puma G-WNSB impacted the sea on approach to Sumburgh Airport in the Shetland Islands. The AAIB report is 266 pages long. This article is intended to highlight some of the key aspects of this comprehensive report. The CHC helicopter, chartered by Total, was making a 3 sector flight to Aberdeen from the Alwyn North installation in the East Shetland Basin, via the Borgsten Dolphin drilling rig and Sumburgh (for a refuelling stop, following a relatively late manifest change to add an extra passenger on the return flight). The helicopter capsized and four passengers died, the first fatalities in a survivable water impact of a helicopter on the UK Continental Shelf since the Cormorant Alpha accident in 1992. The Crew The G-WNSB Aircraft Commander was an experienced Super Puma pilot who had approximately 15 years experience on the L1 Super Puma [sic] and 3 years experience (1894 flying hours) on the L2 Super Puma. The Co-Pilot had been a flying instructor on single engine, single pilot aircraft at a different company with approximately 3000 flying hours but was new to Super Puma operations. He had been with the company for only a year, initially training on 225 Super Puma but then retrained onto the L2 Super Puma, qualifying in February 2013. The Co-Pilot had approximately 400 flying hours on the L2 Super Puma. The Accident Flight Meteorological data for Sumburgh at the time indicated broken cloud at 300ft, with 2,800m visibility. The AAIB say: The commander was the Pilot Flying (PF) on the accident sector. The weather conditions were such that the final approach to Runway 09 at Sumburgh Airport was flown in cloud, requiring the approach to be made by sole reference to the helicopter’s instruments, in accordance with the Standard Operating Procedure (SOP) set out in the operator’s Operating Manual (OM). The approach was flown with the autopilot in 3-axes with Vertical Speed (V/S) mode, which required the commander to operate the collective pitch control manually to control the helicopter’s airspeed. The co-pilot was responsible for monitoring the helicopter’s vertical flightpath against the published approach vertical profile and for seeking the external visual references necessary to continue with the approach and landing. The procedures permitted the helicopter to descend to a height of 300 ft, the Minimum Descent Altitude (MDA) for the approach, at which point a level-off was required if visual references had not yet been acquired. Although the approach vertical profile was maintained initially, insufficient collective pitch control input was applied by the commander to maintain the approach profile and the target approach airspeed of 80 kt. This resulted in insufficient engine power being provided and the helicopter’s airspeed reduced continuously during the final approach. Control of the flightpath was lost and the helicopter continued to descend below the MDA. During the latter stages of the approach the helicopter’s airspeed had decreased below 35 kt and a high rate of descent [up to 1,800 fpm] had developed. The decreasing airspeed went unnoticed by the pilots until a very late stage, when the helicopter was in a critically low energy state. The AAIB characterise this as “consistent with entry into a Vortex Ring State,...
read moreGermanwings: Psychiatry, Suicide and Safety
Germanwings: Psychiatry, Suicide and Safety The French Bureau d’Enquêtes et d’Analyses (BEA) has issued their report into the loss of Germanwings Airbus A320 D-AIPX and 150 lives in the French Alps on 24 March 2015, which was due to the actions of the Co-Pilot. Below we focus on the highlights from the 110 page report. The Co-Pilot The BEA summarise the career of the 27 year old Co-Pilot Andreas Lubitz as follows: between January and April 2008, he took entry selection courses with Lufthansa Flight Training (LFT); on 1 September 2008, he started his basic training at the Lufthansa Flight Training Pilot School in Bremen (Germany); on 5 November 2008 he suspended his training for medical reasons; on 26 August 2009 he restarted his training; on 13 October 2010, he passed his ATPL written exam; from 8 November 2010 to 2 March 2011, he continued his training at the Airline Training Centre in Phoenix (Arizona, USA); from 15 June 2011 to 31 December 2013, he was under contract as a flight attendant for Lufthansa while continuing his Air Transport pilot training; from 27 September to 23 December 2013, he took and passed his A320 type rating at Lufthansa in Munich (Germany); on 4 December 2013, he joined Germanwings [a Lufthansa subsidiary]; from 27 January 2014 to 21 June 2014, he undertook his operator’s conversion training including his line flying under supervision at Germanwings; on 26 June 2014, he passed his proficiency check and was appointed as a co-pilot; on 28 October 2014, he passed his operator proficiency check. The BEA say: In 2008, 384 pilots out of a total of 6,530 applicants were selected to start training at the LFT centre. The co-pilot…was the holder a class 1 medical certificate that was first issued in April 2008 and had been revalidated or renewed every year. In August 2008, the co-pilot started to suffer from a severe depressive episode without psychotic symptoms. During this depression, he had suicidal ideation, made several ‘no suicide pacts’ with his treating psychiatrist and was hospitalized. He undertook anti-depressive medication between January and July 2009 and psychotherapeutic treatment from January 2009 until October 2009. His treating psychiatrist stated that the co-pilot had fully recovered in July 2009. Since July 2009, this medical certificate had contained a waiver…This waiver stated that it would become invalid if there was a relapse into depression. The copilot had had to pay 60,000 € to finance his part of the costs of his training at LFT [150,000€ in total]. He had taken out a loan for about 41,000 € to do so. A Loss-of-License (LOL) insurance contracted by Germanwings existed and would have provided the co-pilot with a one-time payment of 58,799 € in case he had become permanently unfit to fly in the first five years of employment. This type of insurance is contracted for all Lufthansa and Germanwings pilots until they reach 35 years of age and complete 10 years of service. The co-pilot did not have any additional insurance that would cover for potential future loss of income in case of unfitness to fly. In an e-mail he wrote in December 2014, he mentioned that having a waiver attached to his medical certificate was hindering his ability to get such an insurance policy. The BEA explain that: Pilots must declare on...
read more2009 Newfoundland S-92A C-GZCH Accident: A Failure of Design and Certification
2009 Newfoundland S-92A C-GZCH Accident: A Failure of Design and Certification 12th March marks the anniversary of the 2009 loss of a Sikorsky S-92A off Newfoundland, Canada after two (of three) mounting studs, holding the Main Gear Box (MGB) oil filter failed, allowing a massive MGB oil loss. While 17 people died in that preventable accident, fortuitously one passenger, Robert Decker, survived (video of his eyewitness account). Controversially, following a failure during Sikorsky certification testing in 2002, the US Federal Aviation Administration (FAA) had allowed the certification of the type with a uniquely lax interpretation of the certification requirements for loss of lubrication testing. “Truth in politics is optional – Truth in engineering is mandatory.” Igor Sikorsky (1889-1972) Despite misleading social media statements by the then Sikorsky S-92A Project Director (albeit countered by others as mentioned by the TSB) that the MGB had been tested for 3 hours, with a genuine loss of lubricant the MGB disintegrated in just 11 minutes. A Preventable Accident The Canadian Transportation Safety Board (TSB) reported in 2011 on the accident to Cougar S-92A C-GZCH Flight 491. The TSB said the: …mounting studs had fractured by overstress extension of fatigue cracks. Fretting and rub patterns observed on the filter housing and packing indicated that the fatigue cracking developed in the forward stud, causing it to fail, which increased the load on the aft stud leading to its failure. Such failures of MGB filter mounting studs (or bolts) is not unheard of (in these cases on Australian operated WHL Sea King Mk 50s): Source: SURVEY OF SERIOUS AIRCRAFT ACCIDENTS INVOLVING FATIGUE FRACTURE VOL. 2 ROTARY-WING AIRCRAFT by Glen S. Campbell, R.T.C. Lahey National Aeronautical Establishment (Canada, 1983). TSB state: On 06 August 2002, Sikorsky carried out its initial certification loss of lubricant test by draining the MGB and using only the remaining residual oil (approximately 1.3 gallons) then continuing operation in accordance with the requirements of AC 29-2C. The purpose of this test, outlined in the test documentation, was to demonstrate that the S-92A transmission could provide, “continued safe operation for a minimum of 30 minutes following a complete loss of lubricating oil in accordance with the requirements of FAR 29.927(c)(1).” … Sikorsky and the FAA expected that, based on the similarities between the S-92A’s MGB and the Sikorsky S-60 [sic: H-60 / S-70] Black Hawk‘s MGB, the S-92A’s MGB would successfully operate for 30 minutes after draining the lubricating oil. The FAA indicated that the initial test was thought to be a low risk test, and Sikorsky scheduled it very late in the overall S-92A certification program. This original S-92A test matched the way other manufacturers conducted such a loss of lubrication test. TSB explain that: EASA indicated that applicants in its jurisdiction normally complied with Part 29.927(c)(1) by draining the MGB and continuing operation with only residual oil. Prior to the S-92A certification validation it had already tested and certified at least four helicopters using this criterion. Aerossurance is aware that Canadian manufacturers also followed the same interpretation as the European manufacturers. Unfortunately with just 1.3 gallons of oil the S-92A MGB: …suffered a catastrophic failure about 11 minutes after the test was started. TSB go on: Following the loss of lubricant test resulting in catastrophic failure, instead of taking steps to redesign the transmission to provide a 30 minute run dry capability [sic: this term is not used in regulation] for the MGB, Sikorsky re-visited the requirements...
read moreStep Change in Safety: Helicopter Safety Update 2016
Step Change in Safety: Helicopter Safety Update 2016 Step Change in Safety held a webinar on North Sea helicopter safety (covering CA-EBS, emergency egress, FCOMs and airworthiness matters) on 9 March 2016 (following on from a March 2015 event we have previously covered). Introduction Step Change is a tripartite UK offshore health and safety organisation combining companies, unions and regulators, formed in 1997. The organisation has 5 strategic themes, each with a steering group: Asset integrity Competence & human factors Workforce engagement Simplification (and standardisation) Helicopter safety Les Linklater, Executive Director of SCinS, briefed on the activity of the Helicopter Safety Steering Group (the HSSG). In particular he discussed the introduction of Category A Compressed Air- Emergency Breathing Systems (CA-EBS) and passenger size procedures following the UK Civil Aviation Authority (CAA) CAP1145 report published 20 February 2014. Category CA-EBS We have previously discussed at length the rapid development, certification and introduction of the Survitec Mk50 Passenger Lifejacket with a Compressed Air EBS (CA-EBS). The earlier LAPP Jacket with a hybrid rebreather has recently been withdrawn from HUET training with the introduction of a new OPITO Basic Offshore Safety Induction and Emergency Training (BOSIET) and Further Offshore Emergency Training (FOET) standard (which we have previously discussed). The Mk50 lifejacket is now used, however ‘wet’ CA-EBS training has not been introduced as yet. It was noted that the CA-EBS is a “fundamentally better” system than the previous hybrid rebreather and the goal is to introduce wet training. The UK regulator, the Health and Safety Executive (HSE), “perceive a risk” of barotrauma for repeated ascents from a depth of 1.5m during HUET. This was called a “minuscule’ risk but one that that “needs to be managed”. It was suggested during Q&A that it was originally understood that the HSE would waive certain requirements of the Diving at Work Regulations during HUET training but that a “risk averse” position is currently being taken. Engagement on the medical requirements are still on-going. Participants made positive comments about the revised HUET training but there was support for resolving the issues to allow wet training. In the UK the Survitec Mk50 passenger lifejacket and CA-EBS in use. Two performance reviews have been successfully held with Survitec on the Mk50 jacket. Survitec Mk51 and Viking jackets with CA-EBS are to be used for flight crew. CA-EBS implementation is estimated to have cost about £20 million across the UK workforce. Passenger Size Passenger size has also proved an implementation challenge, hence the decision to focus on bi-deltoid shoulder measurement as an appropriate single measurement which can be done by trained offshore medics. Implementing this measurement programme was a ~£1 million investment to measure 75,000 people. Passengers classified as Extra Broad (XBR) have bi-deltoid measurement >22in. XBR passengers must seat in selected, marked seats with escape routes compatible with their size. Over 75,000 UK offshore personnel have been measured, only 3% are XBR and none the Super XBR category. As 30% of seats in the current fleet are XPR compatible (shaded grey in the diagram below) it is unlikely this restriction will every adversely affect any individual flight. It has been decided that only those with an initial measurement of over 20in will be re-measured every 4 years (prior to HUET training and ideally, for simplicity and efficiency, by offshore medics). There had been feedback that the XBR seating is not consistently occurring on return journeys (were Helideck Landing Officers [HLO] are...
read moreShell Pernis 11.2t Ethylene Oxide Leak
Shell Pernis 11.2t Ethylene Oxide Leak The Dutch Safety Board has reported (in Dutch) on the leak of 11.2 tonnes of ethylene oxide from a overhead pipe at the 550 hectare Shell Pernis oil refinery on 30 December 2013. The leak was detected by a site worker at what is Europe’s largest refinery, surrounded by 500,000 inhabitants. Ethylene oxide is toxic, carcinogenic, ignites easily and may explode. The DSB say their investigation shows that Shell was not prepared for such a leak of that size. The adjacent port had to be evacuated due to the level of airborne contamination, and a water curtain used had the side effect of increasing the ground contamination. The spill occurred because the insulated pipework joints has degraded internally over 18 years. The DSB say that Shell had assumed a 40 year design life and that the joints would be maintenance free for 20 years. Following the spill, Shell has taken a series of measures. The joints have been replaced by flanges which can be routinely inspected. Shell now uses technical means to detect leaks in a timely manner and emergency procedures have been revised. Not The Only Leak Shell had suffered leaks of the same chemical in 2007 and 2009. During the completion of this report, the DSB launched an investigation into the emission of another 25 tonnes of ethylene oxide at a sister plant at Shell Moerdijk. It is alleged that this leak, following a repair in November 2015, was only discovered 2.5 months later. We have also previously reported on an earlier explosion there: Shell Moerdijk Explosion: “Failure to Learn” UPDATE 10 August 2016: It is reported that the UK Health and Safety Executive (HSE) have issued an Improvement Notice to Shell in the UK on its Clipper Southern North Sea complex of five bridge linked platforms, after one of their inspectors warned that: …“significant changes” to the Clipper installation meant there was risk of loss of containment from corrosion under insulation (CUI). In one instance, a four inch condensate line had to be shut down after it was discovered the thickness of the wall was just 2.6mm – a significant decrease on its nominal measurement of 11.1mm. A notice from the HSE also said “certain hydrocarbon containing lines” were three years behind their planned inspection date while certain lines had not been inspected for more than 12 years. But further: It was also found Shell had reduced its CUI inspection and repair programme staffing in March from 24 persons to eight people, which reduced the “ability to execute inspection and repairs in a timely manner”. In the 2008 book Resilience Engineering Perspectives, Volume 1: Remaining Sensitive to the Possibility of Failure, John Wetherall writes: …one hallmark of a resilient organisation is that it is prepared not only for its own failures those of which it can learn from others – the more resilient it is, the ‘bigger’ are the lessons it has learnt from others. Aerossurance has extensive safety and accident analysis experience. For aviation advice you can trust, contact us at: enquiries@aerossurance.com Follow us on LinkedIn and on Twitter @Aerossurance for our latest updates. TRANSLATE with x English Arabic Hebrew Polish Bulgarian Hindi Portuguese Catalan Hmong Daw Romanian Chinese Simplified Hungarian Russian Chinese Traditional Indonesian Slovak Czech Italian Slovenian Danish Japanese Spanish Dutch Klingon Swedish English Korean Thai Estonian Latvian Turkish Finnish Lithuanian Ukrainian French Malay Urdu German Maltese Vietnamese Greek...
read moreForgotten Fasteners – Serious Incidents
Forgotten Fasteners – Serious Incidents We examine three incidents where fasteners were forgotten during maintenance. It two cases these maintenance errors resulted in parts falling from the aircraft. In a third, a massive fuel leak occurred. Incident 1 – Twin Otter Mission Pod The Irish Air Accident Investigation Unit (AAIU) has recently reported on a serious incident that occurred on 15 August 2015 involving DHC-6-300 Twin Otter C-GSGF, used for aerial survey work by Sander Geophysics Ltd (SGL). Incident 1 – The Flight The aircraft was in Ireland for the low-level Tellus survey project of the Geological Survey of Ireland: The aircraft is equipped with three geophysical instruments which measure the magnetism, radioactivity and conductivity of the Earth below. It undertakes measurements as it flies at a speed of approximately 130 mph (approx 216km/h). The aircraft flies at 60 m (196 ft) above ground level… Survey lines are flown at a spacing of 200 m. The AAIU say: On take-off from Weston Airport, County Kildare the nose cone from the right hand mission equipment pod fell from the aircraft… The Flight Crew experienced a significant amount of yaw to the right which they felt through the flying controls. The aircraft diverted to Dublin Airport where it subsequently landed safely. There were no injuries. One of the three sensors in use was an Electro Magnetic (EM) system. A signal is transmitted from the right hand wing tip pod and the signal is received in the left pod. Incident 1 – The Safety Investigation The AAIU say: On 14 August 2015, the day before the event, in accordance with the maintenance instructions prescribed in the [mission modification’s Supplemental Type Certificate] STC, the aircraft underwent a 125 hour Supplementary Inspection. This inspection called, inter alia, for the removal of “the EM pod nose and tail cones” and inspection of “the pod internal frames for cracks or other damage”. …the Operator’s standard practice calls for the fitting of flagging tape when parts are removed and that the flagging tape should only be removed following re-installation of the removed part(s). On this occasion the personnel involved advised the Investigation that flagging tape was not fitted. It was reported that during the EM Pod maintenance, while the nose cone was being reinstalled, a fault was detected with its sensor system. Re-installation of the nose cone was halted pending identification of the cause of the fault and consequently only the top two nose cone retaining screws were re-installed. Troubleshooting subsequently traced the origin of the sensor problem to a location inboard of the pod and the fault was rectified. The Inspection was then completed but the 14 remaining nose cone retaining screws were not re-installed. The AAIU say: All personnel who completed walkaround inspections on the morning of the event had completed a third party, computer based Aviation Maintenance Human Factors course… There is no mention of the use of more interactive or tailored training. The check was recorded in the Tech Log but it would not necessarily have been apparent that the nose cone had been removed to the crew. The Flight Manual Supplement does have a requirement to “check that all visible attaching fasteners are installed and secure”. The Commander said that he “…there’s not any moving parts on the pods. I had a cursory look at the pods probably from about fifteen feet ahead...
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