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Bristow S76 Ditched in Nigeria today Feb 3 2016

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Bristow S76 Ditched in Nigeria today Feb 3 2016

Old 21st Mar 2016, 12:30
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We all appreciate your expertise in S76 Copterline and your willingness to help solve these issues. But what's the point? You are wasting your time. The facts are: 1. The nigerian crew, especially the lady captain, are heroes. 2. Bristow passed their "audit" with flying colors, demonstrating once again that they are nigeria's best operator and, most probably, the world's too. All due to their wonderful and ever present "target zero" slogan.
3. The S76 is the best helicopter ever built (well, if you ask sikorsky or bristow) and neither will ever admit openly that there is anything wrong with it.
These recent accidents will soon be forgotten (in fact the august 2015 one was until this "water landing" happened).
They were solved at very very low cost for bristow and now they can all get back to their busy lives of fake smiles, fake slogans (like taget zero) and running their "cash cow": nigeria
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Old 21st Mar 2016, 12:38
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I see tgvbhy15 is back with his usual invective. Doubtless he will be going in to work with his fake smile and fake friendship with his work colleagues whilst using his anonymity to slag them off behind their backs on this forum
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Old 21st Mar 2016, 15:00
  #503 (permalink)  
 
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@tgvbhy15
But what's the point? You are wasting your time.
Don't worry. I hope that this world is changing. Who was able to think a year ago that the VW scandal can be published? Not many! I hope that the VW scandal will make this world to be cleaner. In the other hand let's make this world to be safer for the crews and passengers.

I don't feel at all that I have waste my time. Let's wait until the 12th August, 2015 and 3rd February, 2016 accidents helicopter's fluid contamination analyzes will be published (I hope that the samples haven't been lost on the way to the laboratory?)
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Old 21st Mar 2016, 19:38
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Copterline. I honestly hope too that your efforts are not in vain and thank you for sharing your knowledge and efforts.
Unfortunately, being here in nigeria and seeing upclose what really goes on "behind the scenes" makes you become cynical, and that's why I said that you were wasting your time. Nothing personal :-)
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Old 21st Mar 2016, 21:54
  #505 (permalink)  
 
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@tgvbhy15
I'm very pleased to share my knowledge with everybody who is working with S76 series helicopters. I have had change to read documents which are not public documents. Due to this; my understanding for consequences and the root cause is so clear. I'm very disappointed to see how some of the interest parties are willing to misslead investigators, pilots and technicians to change the focus from actual root cause to the consequence.

For example the 12th August, 2015 the preliminary report of the accident, together with issued AD, changed the focus to the Control rod, the Control rod end and the locking nut. The finding was that the Control rod and the rod end have separated. A lot of noise was created to inspect if the locking nut is not in place and an AD and ASB were issued....it is like David Copperfield who makes you see what he wants you to see.

The Control rod and the Control rod end separation during the flight are almost impossible if the helicopter behaves normally. When the helicopter is behaving normally the flight controls work load (resistance load of flight controls, mixing unit, control rods) is only 5 lbf. This is due to the fact that the hydraulic power (Servo Actuators) is making the power work behalf of PF.

If you consider the fact that the Control rod tube and the Control rod end has come loose and entered through a thread. Everyone can make on evaluation that the 5 lbf work load is not enough to cause this Control tube and the Control rod end separation.

If you consider that if the case is that the flight controls are jammed and two dying man are fighting against jammed flight controls by using the power of adrenalin. You can only evaluate how huge the forces of the two dying man can achieve?

In the Baltic Sea accident the 10th of August, 2005 the Commander was able to bend the his control stick forward. The copilot together with the captain were fighting against jammed flight controls until they were able to brake the control tube and the control rod end which is connecting copilot's and captain's control sticks.

All of this (above) was verified from the FDR, CVR and by the physical evidences from the helicopter wreckage.

Even in the theory the possible missing locking nut has no influence on the strength of Control rod tube and the Control rod end. The locking nut is needed to secure that the length of the Control rod assembly will be fixed and any unplanned Control rod end rotation (bolt thread) could not happen which could change the length of the Control rod assembly. This only during the maintenance action when the Control tube assembly is disconnected for the helicopter. At time when the Control tube assembly is connected to the helicopter the Control tube and the Control rod end is not able to rotate because it is attached by the bolts in the both ends.

The conclusion is: the control rod assembly can't be separated by 5 lbf. work load but two dying man could have enough power to brake this Control tube assembly e.g. if the flight controls are jammed.

We have to memorize that the S76 series helicopters are or should be certified under the FAA's transportation helicopter category requirements?

Last edited by Copterline 103; 21st Mar 2016 at 22:06. Reason: Typo corrections
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Old 22nd Mar 2016, 12:24
  #506 (permalink)  
 
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Cop103 you mention many interesting things but surely even a first year metallurgist could tell the difference between a thread that has failed through looseness (chaffing and wear) and a thread that has suffered sudden shear overload? The latter would have rolled over thread crowns etc.

You are very cynical of the investigators but I cannot believe the NTSB and Nigerian AAIB would ever falsely manipulate evidence. Are you falling into the trap of trying to make the evidence match your personal theory?
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Old 22nd Mar 2016, 15:35
  #507 (permalink)  
 
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The lock nut does more than prevent rotation of the rod end. To assemble anything there has to be a clearance unless you are assembling using an interference fit. The interference process is not usable for a rod end that requires adjustment.

The second function of the lock nut is to draw the male and female threads together and prevent movement and fretting.
If the nut is loose there will be motion between the two threads dependent on the tolerances that the threads have been manufactured too. More than possible that the female could be at maximum and the male at minimum. The further out that the rod end is adjusted the less support there will be and the less resistance to fretting.

If this condition existed for an extended period then the threads will gradually be destroyed and the rod end released. If the tube is aluminium and the rod end steel then this process will gradually speed up. I do not know what the S76 tube is made from but the eye will be steel and as the rod is below the servo a good chance it will be aluminium.

I would conclude that there is a good chance that the rod end was loose for some time leading to excessive thread wear and release of the rod end.
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Old 22nd Mar 2016, 21:24
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@Sanus
You are very cynical of the investigators but I cannot believe the NTSB and Nigerian AAIB would ever falsely manipulate evidence
My experience since last ten years with 60.000 non-public accident related documents has opened my eyes. My opinion is that the NAIB is the most accountable of these related parties.

Sanus don't be naive, please!

The FDR, FDAU and cockpit camera's (CIR) data has been lost! Think about this. Maybe the hot and high conditions has destroyed this data of HDG, PITCH, PEDALS, CONTROL STICK?

The probability of this event with all three different systems fails is 1:10000000000 => absolutely possible, almost likely!

The good news are: HUMS system is picking up all the missing information and the HUMS system is using its own sensors and pick-ups. The FMS/GPS will preserves short history data (integrated circuits) of airspeed, ground speed, heading, altitude..... This capability is needed for the dead recording function! There is still a possibility that the truth and nothing but the truth...

Last edited by Copterline 103; 22nd Mar 2016 at 21:39. Reason: Typo corrections
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Old 23rd Mar 2016, 03:56
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Wasn't FDR validation testing one of the aspects picked up on by the post accident audit? The FDR had to be periodically tested to ensure that all parameters were being recorded, I don't think Bristow had been doing this. I'd be surprised if there had been any undue interference with the data before the FDR had been shipped to the UK; probably just lack of maintenance oversight that it wasn't working properly.

Please bare in mind that some operators have been flying S76 safely for 35 years without a single accident. Safe operation depends on the pilots flying them and the mechanics maintaining them. If there was an inherent flaw in the S76 flight control system design then loss of control accidents would be more prevalent than what history shows.

I'm sure they'll be able to unravel the circumstances of what happened to the Bristow accident despite not having a full set of FDR data. I still suspect there was an electrical gremlin that suckered the crew into thinking they had a flight control mechanical problem.
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Old 23rd Mar 2016, 09:01
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@gulliBell
The FDR had to be periodically tested to ensure that all parameters were being recorded
This periodical test is a mandatory test which must be done in every 12 months period. This annual test is not a test that the FDR is recording, this is the test what verifies that the recordings are correct and exactly following the position of e.g. flight controls. Before this test you have to follow (in ground and hydraulic ground power mule connected) precise instruction to move step by step the helicopter's flight controls. The aim of this test is to verify that the FDR recording is 100 % matching to the created series of the control movements. This annual test is normally made by using special software to print out the FDR recording data by the approved maintenance organization or by sending the FDR unit to the Penny & Gilles for the annual test. This Penny & Gils FDR is combined with CVR to be Penny & Gils FDR/CVR.

The functionality test is mandatory to perform before every flight. Penny & Giles FDR/CVR test is the item which should be a check list item. Before commencing a flight the commander has a responsibility to perform FDR/CVR test. This test will ensure that the FDR/CVR works perfectly and its network of sensors and pick-ups are connected to transfer data to the FDR/CVR unit.

The test is a simple push button test. If I right remember when the test is activated the Penny & Giles test panel shows “TEST” and if the test is not passed a “FAIL” caution will illuminated. If the FAIL caution is illuminated then the crew should follow company’s approved MEL procedures. This Penny & Giles FDR/CVR is a combined unit and in EASA world there is not much to do rather than to ground the helicopter until the defect is fixed. In EASA world the helicopter will come unairworthy if FDR/CVR is U/S. I’m not familiar FAA or NCAA ruling of this but don’t believe that under FAA or NCAA doesn’t allowed to operate S76 helicopter without FDR/CVR in commercial operation, commercial offshore operation (OGP).

The helicopter operator is required to have a CAMO. This organization is responsible for the helicopter’s airworthiness and that all the maintenance action will be order to do by a approved maintenance organization in timely manner. Each helicopter must have an approved maintenance program where e.g. FDR/CVR’s all maintenance intervals and maintenance action must be descript. The CAM is responsible to create work orders to cover all the necessary and all the mandatory maintenance action which must be performed within the issued due flight hours, calendar times and cycles (e.g. landings and engines) and all affecting SB's, ASB's and AD's must be taken account.

Every helicopter’s airworthiness has to be double check by Airworthiness Review Certificate (ARC). This review must be done annually by the accepted organization which is commonly the CAMO organization. The aim for this review process is to ensure that the maintenance program is covering all the required maintenance actions and tasks. In addition the review double check that all maintenance action has been (in the past) performed, performed in timely manner and all maintenance documents are objectively and carefully filled.

I can’t believe that Bristow Helicopter has skipped this FDR/CVR annual and a mandatory test. I can’t believe that the Bristow Helicopter operation (training & flight activity) culture could accept that some of the mandatory company test procedures are skipped e.g. FDR/CVR test.

The lost data will be picked up from the HUMS unit's memory disc and from GPS/FMS internal memory so "the truth is still out there".

@gulliBell
If there was an inherent flaw in the S76 flight control system design then loss of control accidents would be more prevalent than what history shows.
Let’s postpone this matter to the near future until we have e.g. data of these two accidents hydraulic fluid contamination or non-contamination. Anyway, you can prepare yourself be surprised...

Last edited by Copterline 103; 23rd Mar 2016 at 09:52. Reason: Typo corrections
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Old 23rd Mar 2016, 10:59
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I've never done a pre-flight FDR/CVR test before, didn't even know it was something that needed to be tested. I just assumed FDR/CVR was one of those optional things that you didn't need in a helicopter < 5700kg MTOW.

I just checked the MMEL, sure enough, FDR is Cat A for some classes of operation....
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Old 23rd Mar 2016, 11:58
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@gulliBell
I've never done a pre-flight FDR/CVR test before, didn't even know it was something that needed to be tested. I just assumed FDR/CVR was one of those optional things that you didn't need in a helicopter < 5700kg MTOW.

I just checked the MMEL, sure enough, FDR is Cat A for some classes of operation....
Do you have or do you have had a S76 type rating? Are you familiar with Penny & Gils FDR/CVR?

My understanding is that EASA and FAA requires FDR/CVR to be installed all twin engine helicopters where the helicopter's type certificate has the approved passenger seats to be ten or more. This is a mandatory safety equipment in the helicopter industry.

The modern offshore helicopters are equipped with HOMP (Helicopter Operation Monitoring Program) or with FDM (Helicopter Flight Data Monitoring) systems. This is a requirement of the customer (OGP).

Sikorsky has not sold any S76 helicopters since the last 20 years without FDR/CVR. The most likely they want to know how it happened, when the event has occurred.
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Old 23rd Mar 2016, 12:19
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We took 3 seats out of our helicopters and convinced the regulator that was enough reason to escape the 10 passenger seat rule...obviously makes life a lot easier for all sorts of reasons.

In 3,800 hours S76 offshore I never checked the FDR once, nobody ever did. We were never told we had to, or how to, or that an FDR was even fitted. I don't even recall a CVR being fitted in the 76 A or C, but I do know we had them in the C+ and C++ because there was a black box in the cockpit with an erase button and annoying green lights that blinked when you spoke.
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Old 23rd Mar 2016, 13:16
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We took 3 seats out of our helicopters and convinced the regulator that was enough reason to escape the 10 passenger seat rule...obviously makes life a lot easier for all sorts of reasons.

In 3,800 hours S76 offshore I never checked the FDR once, nobody ever did. We were never told we had to, or how to, or that an FDR was even fitted. I don't even recall a CVR being fitted in the 76 A or C, but I do know we had them in the C+ and C++ because there was a black box in the cockpit with an erase button and annoying green lights that blinked when you spoke.
Ups,
Very interesting! Didn’t you and your regulator ever realize that the ten or more seats rule is defined from the helicopter type certificate, not on the seats what you kicked out?

Yes, you are right that there are some black boxes in the helicopter and also could be a black box in the cockpit. Don’t press any button if you don’t know what the button is.

Did you had any conversion training, recurrent training, OPC’s, LC’, any annual recurrent system training for S76 series helicopter? Is it a long time since all this happen?

Last edited by Copterline 103; 23rd Mar 2016 at 15:37. Reason: Typo corrections
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Old 23rd Mar 2016, 16:13
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When the oil company owns the whole show, including the helicopters, life becomes so much easier.
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Old 23rd Mar 2016, 16:42
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In Europe, the requirement for a CVR/FDR is driven by a MCTOM of 3175kg, not seating capacity - unlike FARs.

This is from the ICAO Annex 6 Recommendation. In 2018 the discriminant will drop from 3 180kg to 2 250kg - for all new turbine type certificates.

Jim
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Old 23rd Mar 2016, 23:18
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@Sanus
Cop103 you mention many interesting things but surely even a first year metallurgist could tell the difference between a thread that has failed through looseness (chaffing and wear) and a thread that has suffered sudden shear overload? The latter would have rolled over thread crowns etc.
Sanus, my knowledge is not limited to my first year metallurgist. You should remember that the 60.000 non-public documents have included specialist metallurgist reports e.g. from MIT. I’m counting on these MIT's experts knowledge and the experts reports what I have seen.

Your opinion that the control tube and the control rod end has separated as “has failed through looseness (chaffing and wear)”. If this has been the case then the question mark will come over Bristow’s maintenance organization and the technicians. I can't believe that the Bristow’s technicians will bypass during PFC or Daily Check (whatever is the used name for daily inspection) were the S76’s “formula” is open. This is an area of technician interest to check the condition of each Servo Actuators, links, rods, tubes, locking pins, safety wires, visual locking markings, fluid levels, bearings play, leakages ect.

Every technicians of S76 type knows that the area under the “formula” is the most critical area for the safety. If the scenario is like you descript “has failed through looseness”. This development will take time to be separated. The time what is needed to make this looseness to be a separation is not a short time. During this long time this defected control tube and the control rod end should be passed quite many technician's eyes and hands. This doesn’t make sense for me and doesn’t make sense for Bristow’s maintenance organization.

The flight crew should have an indication (during hovering) that the basic, neutral position of control stick has removed and also the play on the rod assembly makes the most likely the helicopter to be unsteady because the flight controls rigging is changing all the time...

The FAA's certification requirement for the helicopter type certification insists that the all critical components or systems should ensure the continuity of safe flight. The all critical components of the all critical systems must be:

1. Redundant (dual systems, hydraulic systems, electrical systems, ect.)
2. Fail safe (single rods, links, tubes, ect.)

This Control rod tube and the control rod end belong to under of the requirement of FAIL SAFE. When the control tube and the control rod end have separated the mandatory requirement of fail safe component doesn’t exist. This is the helicopter type certification requirement. The S76 helicopter is certified under the FAA's Transportation Category. This certification could be an issue and the present finding could have an affect to the airworthiness?

We remember that the accident of 12th of August, 2015, where six people lost their lives.
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Old 23rd Mar 2016, 23:42
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What formula?
How is this "formula" defined?
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Old 24th Mar 2016, 03:10
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I think these control system discussions are a diversion. Bristow maintenance would have inspected the flight control components of the whole fleet in infinite detail following the fatal accident. I'd be more interested in exploring what may have happened electrically that may have suckered the crew into thinking they had a mechanical problem.

And as for whether a CVR/FDR is fitted and required parameters are validly recording, as a pilot I don't care about this. If a component is due for testing it with be entered in the technical log, and a maintenance guy will attend to it. If it's due and the entry is open I don't accept the aircraft. If a pre-flight check of a component is required of the pilot it will be written in the body of the RFM, or in a supplement, and I will do it as written.

I have never had reason to check any FDR, pre-flight or otherwise. Is there something the Bristow pilots needed to do pre-flight in relation to the FDR?
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Old 24th Mar 2016, 06:29
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gulli

I have always completed a daily inspection which included testing the CV/FDR .... press the tit and ensure the relevant lights extinguish, simple.

I know that maintenance performs an annual test for the authority to ensure the data from the FDR is correct, standard.

The longer term question for the authority, and in this particular instance for Bristow Nigeria maintenance and their safety culture, is how this was not done and why so many individual items failed to record. This is part of the safety system - for everyone, Zero.
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