Oil rig chopper down at sea (March, 2009)

[CD]

Broken bolt eyed in Sikorsky helicopter crash
U.S. may ground chopper after Canadian experts find part feared at fault in crash off St. John's

Mar 21, 2009 04:30 AM
ASSOCIATED PRESS

WASHINGTON – Canadian safety officials said yesterday they expect the U.S. to ground Sikorsky S92 helicopters like the one involved in a crash off Newfoundland March 12 in which 17 people died.

A spokesperson for the U.S. Federal Aviation Administration confirmed the agency is working on an emergency safety directive related to the S92, but declined to say if it would ground the helicopters.

Les Dorr said the "specific content" and "the timing" of the directive are still being developed.

Yesterday, the Canadian investigators examining the wreckage of the S92 helicopter that crashed into the Atlantic about 65 kilometres off St. John's found a broken component they say may have played a key role in the accident, the federal Transportation Safety Board said.

The component – a broken mounting stud on the S92 helicopter's main gearbox filter bowl – had been the subject of an "alert service bulletin" issued in January by the manufacturer, Sikorsky Aircraft Corp. of Stratford, Conn.

According to the Canadian safety board, the bulletin said the gearbox filter bowl's titanium mounting studs should be replaced with steel mounting studs within 1,250 flight hours or within one year.

The safety board said investigators immediately notified the FAA and the U.S. National Transportation Safety Board of their findings.

"In light of (the safety board's) discovery, the FAA will be issuing an emergency airworthiness directive (about replacing the studs) ... before conducting any other flights," the board said in a statement.

The FAA does not have authority over aircraft outside the U.S., but it communicates regularly with aviation safety agencies worldwide.

Paul Jackson, a spokesperson for Sikorsky, declined to comment on the broken part or the possible grounding.

Cougar Flight 491 crashed as it ferried workers to two oil platforms. The lone survivor, Robert Decker, 27, suffered lung injuries and fractures.

Full article here...

[Widow]

Maher's Family Asking Questions
March 21, 2009

A bereaved father is asking questions about the Search and Rescue response following the Cougar Helicopter crash. Richard Maher is the father of Allison Maher, the 26 year old woman whose body was retrieved from the water immediately following the crash. Maher says the coronor's office told the family Allison had drowned. He says he can't help but wonder what might have happened had the Coast Guard helicopters been closer to the scene, instead of training off Nova Scotia. Maher says some resources should have been left in Newfoundland during the training excercise. In his grief, Richard Maher reached out to the family of Robert Decker.

http://www.vocm.com/news-info.asp?id=34956

[2milefinal]

I really feel for all those involved, BUT.
This is a bit of a what if thing.

For example what if a commuter flight goes down in lets say Lake Superior. Its going to take at least a hour to get out to any Survivors. It would most likely be a U.S. Coast Guard Helicopter.
...all very sad stuff.

[Widow]

The circumstances are totally different, but I cannot help - personally - having a deep understanding of Maher's family feeling of "what if" ... as my husband also drowned while awaiting rescue. When his body was found, I hoped against hope that it had been quick - and learning from the Coroner that it had been anything but quick, added greatly to the devastation I felt. In the end, it continues to be what motivates me to press for change.

That being said, 1 1/2 hours from impact to survivor rescue ... it could have been a lot worse.

[SAR_YQQ]

I feel for the families and friends of those affected by this crash.

Blaming the SAR system, IMHO, is a way for those affected to project their anguish and find somewhere to help lessen their loss. Those of us in the system tend to have rather thick skin and do not take disparaging comments to heart. We listen and hear and feel your loss.

SAR crews need to train and they are rarely ever a static resource. We could post two Cormorants at St-John's and then have a similar accident occur off the west coast of NL or elsewhere - to the same effect. Liabilities in response time must be accepted when you fly, drive, live, etc outside of normal domestic (urban) Canada. If you are driving the Trans-Canada Highway between WAWA and Thunderbay, you can expect that ambulance, fire and police support to be more than an hour away. The same must be expected for aviation outside of major centres.

Again - condolences...

[Inverted2]

I feel for the families and friends of those affected by this crash.

Blaming the SAR system, IMHO, is a way for those affected to project their anguish and find somewhere to help lessen their loss. Those of us in the system tend to have rather thick skin and do not take disparaging comments to heart. We listen and hear and feel your loss.

SAR crews need to train and they are rarely ever a static resource. We could post two Cormorants at St-John's and then have a similar accident occur off the west coast of NL or elsewhere - to the same effect. Liabilities in response time must be accepted when you fly, drive, live, etc outside of normal domestic (urban) Canada. If you are driving the Trans-Canada Highway between WAWA and Thunderbay, you can expect that ambulance, fire and police support to be more than an hour away. The same must be expected for aviation outside of major centres.

Again - condolences...

Good Post! In a perfect world there would be ambulances and helicopters everywhere but in the real world sometimes help takes time.

[r22captain]

Adding to SAR_YQQ's comment.

Was it not Cougars SAR machine that brought back the survivor? That's the reason the oil companies require/contract that service. It was worth everypenny right there IMHO

I'm currently on a 24/7 Medi-vac standy-by job for a oil company for the same reason. Nearest air amblance is 1.5 hours away and we're 0.5. Nearest SAR is way longer then that. But I feel what the families are feeling as they may not totally understand right now due the the uncontrolable emotions they are going through.

My thoughts and prayers continue to everyone envolved in this.

[airbournesailor]

First, I'd like to say that our SAR guys do an amazing job and risk their lives daily saving many lives, I've seen this many times. I do know that after almost every tradgedy at sea the response time is almost always questioned by friends and relatives of the victims, which is understandable when you lose someone close. I don't think, but who knows, that a closer SAR would have made a difference in this tradgedy. However, what about in a future event? One of the reccommendations of the Ocean Ranger inquirery (SP) was that a SAR helicopter be placed in YYT. With all the activity in the area offshore, maybe it's something that needs to be looked at in the future. I'm certainly not an expert in this area and I'm not saying there definitely should be one there, but I think it is something that should be studied and investigated. I do understand that Cougar provides SAR, but I can only assume that they are no where near the training levels of our dedicated SAR teams.

[r22captain]

One of the reccommendations of the Ocean Ranger inquirery (SP) was that a SAR helicopter be placed in YYT.

And that's why Cougar's SAR machine is there. The oil companies took it upon themselves.

I do understand that Cougar provides SAR, but I can only assume that they are no where near the training levels of our dedicated SAR teams.

http://www.cougar.ca/images/pdf/sar.pdf

They saved someones life did they not. Pretty skilled people to me. Not trying to argue with you at all. Cougar has a highly skilled team, train constantly and are a sought after service.

[armchair]

One issue which was not discussed here in 4 pages of comments (at least I did not see any comments) is at what altitude was the aircraft when it got its first indication of a gearbox malfunction. this has a huge impact on the ability of the pilots to do a controlled ditching. I understand that the aircraft could have been several thousands feet high, which if correct, would have practically sealed the fate of the aircraft.

Now there are several reasons why Cougar would want to fly thousands of feet high, including weather avoidance, flying on top, and performance/fuel consumption - but the obvious downside is how far you gotta go when things go bad. In a chopper, big or small, I will always fly as low as I legally and possibly can, because the shit can hit the fan in a hurry, and I want the least amount of space between mother earth and that helicopter. I have flown IFR in big unpressurized choppers in the past, climbing between 8 to 12 thousand feet, and I always hated that particular aspect of the equation.

With a 4 km debris field as reported earlier, I would assume the pilots did not even have the opportunity to put it down gently. I am looking forward to hear about this aspect of the investigation.

[r22captain]

One issue which was not discussed here in 4 pages of comments (at least I did not see any comments) is at what altitude was the aircraft when it got its first indication of a gearbox malfunction. this has a huge impact on the ability of the pilots to do a controlled ditching. I understand that the aircraft could have been several thousands feet high, which if correct, would have practically sealed the fate of the aircraft.


With a 4 km debris field as reported earlier, I would assume the pilots did not even have the opportunity to put it down gently. I am looking forward to hear about this aspect of the investigation.

http://flightaware.com/live/flight/CHI9 ... B/tracklog

Started off at 9000....quickly down and cruised at 800 for 3-4 minutes...so they had a chance. But time will tell what they were doing. I for one don't want to speculate on this as I this is an emotional subject for myself. But...there is the data....take what you want from it. But I wouldn't say it "sealed the fate" as you put it.

In a chopper, big or small, I will always fly as low as I legally and possibly can, because the shit can hit the fan in a hurry, and I want the least amount of space between mother earth and that helicopter.

I tend to disagree with this. Altitude gives you options. How many places can you auto/choose from 500-1000 feet? not too many....climb to 2000 feet and your options triple. Nothing better in my books then time and altitude.

[carholme]

http://flightaware.com/live/flight/CHI9 ... B/tracklog

[r22captain]

thnx carhomle

[armchair]

Thank you both for the tracking site, I had not seen it. Good point too on keeping some altitude for options.

I can understand the hesitation on speculating what one should, or could, or should not , have done, during those last few minutes. Whether it is said or not, there is enormous pressure on pilots to try to avoid ditching, and the decision to put it in the water is not an easy one. In many if not most "books", a secondary indication (noise, warning light, vibration, smell etc) is the deciding factor. How long do you trudge along on a single indication? that is a tough question. Will pilots ditch an aircraft on a single indication now, as a result of this occurrence? There have been many successful ditchings in the Atlantic and other seas, with no resulting loss of lives. It would be interesting to know what happened in each case, interms of indications - and the decision to ditch.

I think all the other discussions here on SAR, survival suits and response times are peripheral and skirt the real issues. The real issues are how & why the transmission failed, and how the pilots reacted to it. SAR response and suits were top notch.

[carholme]

I don't think I would be too sure about the single indication as there is very little accurate information to go on at this time. The only reported information is that he turmed back with MGB oil pressure problems.

They did find a broken MGB oil filter stud broken and this just happens to coincide with the bulletin released in January. Nobody has stated that this was the cause of the MGB oil pressure problem, though it does seem co-incidental.

There have been "uh ohs", claims that transmissions are to be replaced, and reports of TSB grounding the aircraft. TSB only offer reccomendations, the regulatory agencies of the various countries will decide if groundings take place, based on their information.

Apparently Sikorsky has dispatched repair teams with spares to many of the operators to ensure compliance with the January bulletin.

I would certainly wait until tomorrow to see the results of the FAA decision making process. Until the CVR/FDR tapes are released, we are not going to know for sure what exactly happened in that time period between turning back and contact with the sea.

The condition of the Main Rotor Blades certainly suggests very low, if any rotor rpm on contact.

carholme

[carholme]

S-92 Helicopter Operators Complying Worldwide With Sikorsky Bulletin on Gearbox Oil Bowl Studs
Tuesday, March 24, 2009 - Sikorsky Aircraft Corp.


Sikorsky Aircraft Corp. announced today that the majority of the worldwide S-92(TM) helicopter fleet already has complied with the company's notice to retrofit the aircraft's gearbox oil bowl with steel mounting studs. The company expects to have close to 100 percent compliance by the end of this week. Sikorsky is a subsidiary of United Technologies Corp. (NYSE: UTX).

The company contacted all S-92 helicopter operators on March 20after broken titanium studs were found during a helicopter crash investigation in Canada. The investigation is continuing, and no determination has been made that the broken studs contributed to the accident or if they resulted from it. Sikorsky immediately notified the operators as a safety precaution, and the Federal Aviation Administration is expected to issue an Airworthiness Directive instructing the retrofit.

As of this moment, more than 50 of the 91 S-92 helicopter retrofits were completed. Sikorsky has made available all the parts and tools necessary for all operators to swap out the studs.

"While the investigation remains ongoing, our priority has been to maintain safety and eliminate any potential risks," said Marc Poland, Vice President of Sikorsky Global Helicopters. "The operators are reacting quickly, and we are doing all we can to encourage full and rapid compliance."

Canada's Transportation Safety Board (TSB) is leading the investigation into the March 12helicopter accident that occurred off the coast of Newfoundlandand resulted in 17 deaths. Sikorsky is assisting with the investigation.

"Our prayers and deepest condolences go out to the families of all involved in this terrible tragedy," Poland said. "The investigation continues, and we are providing support and technical resources to assist the TSB while we continue to support the fleet."

The S-92 helicopter was designed with numerous structural and avionics safety features. The worldwide fleet has accumulated more than 140,000 flight hours since 2004. Approximately 66 percent of current S-92 operators are offshore oil customers. The remainder are performing search and rescue (SAR), Head of State, VIP, and airline missions.

Sikorsky Aircraft Corp., based in Stratford, Conn., is a world leader in helicopter design, manufacture and service. United Technologies Corp., based in Hartford, Connecticut, provides a broad range of high technology products and support services to the aerospace and building systems industries.

[carholme]

Emergency Airworthiness Directive: S-92A Main Gearbox Filter Bowl Assembly Mounting Stud - Replacement
Tuesday, March 24, 2009 - FAA


EMERGENCY AIRWORTHINESS DIRECTIVE
Aircraft Certification Service
Washington, DC
www.faa.gov/aircraft/safety/alerts/

U.S. Department of Transportation
Federal Aviation Administration

DATE: March 23, 2009
AD #: 2009-07-53

This Emergency Airworthiness Directive (AD) is prompted by the failure of 2 main gearbox filter bowl assembly mounting studs (studs) that were found broken during a fatal accident investigation in Canada. Prior to the accident, the manufacturer was investigating a July 2008 incident that also involved broken studs. In both cases, the broken studs resulted in rapid loss of oil. The failures have been tied to fretting and galling of the original titanium studs; therefore, we are requiring the removal of all titanium studs and replacement with steel studs. We are issuing this EmergencyAD to prevent failure of a stud which could result in rapid loss of oil, failure of the main gearbox, and subsequent loss of control of the helicopter.

We have reviewed Sikorsky Alert Service Bulletin No. 92-63-014A, Revision A, dated March 20, 2009, which describes procedures for removing the main gearbox bowl assembly titanium mounting studs and replacing them with steel mounting studs.

This unsafe condition is likely to exist or develop on other helicopters of the same type design. Therefore, this AD requires, before further flight, replacing titanium studs with steel studs. The actions must be accomplished by following specified portions of the alert service bulletin described previously.

This rule is issued under 49 U.S.C. Section 44701 pursuant to the authority delegated to me by the Administrator, and is effective immediately upon receipt of this emergency AD.

2009-07-53 SIKORSKY AIRCRAFT CORPORATION: Directorate Identifier 2009-SW-08-AD.

Applicability: Model S-92A helicopters with a main gearbox housing assembly, part number (P/N) 92351-15110-042, -043, or -044, that is not marked with “TS-062-01” near the P/N, certificated in any category.

Compliance: Required before further flight, unless accomplished previously.

To prevent failure of a main gearbox filter bowl assembly mounting stud (stud), which could result in rapid loss of oil, failure of the main gearbox, and subsequent loss of control of the helicopter, accomplish the following:

(a) Remove the titanium studs by following the Accomplishment Instructions in Sikorsky Alert Service Bulletin No. 92-63-014, Rev. A, dated March 20, 2009 (ASB), paragraph 3.A.
Note: Figure 1 of the ASB contains guidance for removal and installation of the studs.

(b) Visually inspect the tapped holes and the main gearbox housing lockring counterbore for damage. If you find damage in the tapped holes or in the main gearbox housing lockring counterbore, contact the Boston Aircraft Certification Office for an approved repair.

(c) Install steel studs and mark the main gearbox housing as “TS-062-01” near the P/N by following the Accomplishment Instructions in the ASB, paragraph 3.C.

(d) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Manager, Boston Aircraft Certification Office, Engine and Propeller Directorate, FAA, ATTN: Kirk Gustafson, Aviation Safety Engineer, 12 New England Executive Park, Burlington, MA 01803, telephone (781) 238-7190, fax (781) 238-7170, for information about previously approved alternative methods of compliance.

(e) Special flight permits will not be issued.

(f) Copies of the applicable service information may be obtained from Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical Support, mailstop s581a, 6900 Main Street, Stratford, CT, telephone (203) 383-4866, e-mail address tsslibrary@sikorsky.com, or at http://www.sikorsky.com.

(g) Emergency AD 2009-07-53, issued March 23, 2009, becomes effective upon receipt.

FOR FURTHER INFORMATION CONTACT: Kirk Gustafson, Aviation Safety Engineer, Boston Aircraft Certification Office, Engine and Propeller Directorate, FAA, 12 New England Executive Park, Burlington, MA 01803, telephone (781) 238-7190, fax (781) 238-7170.

[Widow]

FAA grounds Sikorsky helicopters until part replaced, cites other case

1 hour ago

HALIFAX, N.S. — The Federal Aviation Administration grounded Sikorsky S-92A helicopters Tuesday and ordered operators to replace a gearbox component linked to both a deadly crash in Newfoundland and a close call in Australia.

The U.S. regulator had been expected to issue the emergency directive, which states owners must replace titanium mounting studs on the main gearbox filter assembly with steel ones before they can resume flying.

The order also states that the same studs were found to be broken on another Sikorsky S-92A helicopter that was forced to make an emergency landing after being alerted to an oil problem at a low altitude in Australia last July.

"In both cases, broken studs resulted in rapid loss of oil," the two-page document states.

"We are issuing this Emergency AD to prevent failure of a stud which could result in a rapid loss of oil, failure of the main gearbox and subsequent loss of control of the helicopter."

The order comes in the wake of a deadly helicopter crash off Newfoundland in which 17 of the 18 people on board were killed as they headed to an offshore oil platform on March 12.

The sole survivor is being treated for injuries in a St. John's hospital.

The Transportation Safety Board, which is leading the investigation into the accident, said last week that it had discovered two broken titanium mounting studs on the assembly soon after it began examining the mangled fuselage.

TSB investigators, who are being assisted by Sikorsky and the FAA on the ground in St. John's, N.L., indicated last week that the FAA would be issuing a directive. The administration confirmed Tuesday they had issued the document.

Lead investigator Mike Cunningham said the studs could have been damaged in flight, upon impact, or during the recovery of the helicopter, which is believed to have plunged nose-first into the ocean minutes after the pilot issued a distress call.

The crew declared a mayday due to a main gearbox oil pressure problem and began heading back to St. John's, N.L., but crashed eight minutes later.

The FAA's directive requires the immediate replacement of the mounting studs.

The earlier Sikorsky Alert Service Bulletin, issued Jan. 28, had stated operators should replace the titanium studs with steel ones within a year or 1,250 flight hours.

A spokesman at Sikorsky in Stratford, Conn., did not return calls or respond to emails inquiring about the earlier incident in Australia, which had been under investigation by the manufacturer.

The TSB said Tuesday that it expected the studs to be replaced "in a timely fashion." Sikorsky said Monday that the majority of S-92 helicopters in service - 50 of 91 - had already replaced their mounting studs.

Maryse Durette, a spokeswoman for Transport Canada, said the FAA directive will apply in Canada.

Les Dorr of the FAA said the administration is broadening its examination of the gearbox to determine if there are any safety deficiencies that require attention.

"The FAA believes this action addresses the particular unsafe condition that we know about," he said from Washington, D.C.

"Now we are going to be looking at the design of the gearbox and crew emergency procedures along with Sikorsky to see if there are any other safety improvements that are needed on the gearbox."

Dorr also said the FAA has instructed S-92A operators to disregard procedures Sikorsky recommended in the event of an indication of a problem with the gearbox.

Dorr said a Sikorsky Safety Advisory issued last September advises operators of changes to the Rotocraft Flight Manual, which list the steps crews should follow in emergencies and other occurences.

In particular, Dorr said the revised manual would instruct crews to land the helicopter within a certain amount of time. That differs from the current document which instructs crews to land immediately if there is a gearbox problem.

The FAA said operators should continue using the current flight manual, cautioning that the information in Sikorsky's advisory was "premature and may not be appropriate," and that crews should continue to land immediately in the event of a gearbox failure.

The directive affects the 37 S-92As that are registered in the States, but it was expected other international aviation authorities would follow suit. The FAA's European counterpart immediately adopted the directive on replacing the titanium studs.

http://www.google.com/hostednews/canadi ... ruTqmF1aqw

[MUSKEG]

I am unfamiliar with most Heli's but need to ask. In this heli is it possible to disengage the blades from the gearbox? I believe engine to gearbox yes but gearbox to rotars?. If not then failure of the gerabox and ensuing pile up of gears would bring rotars to a stop or in the event of a rapid stop even seperation of head and or blades right? Jusk asking.

[r22captain]

I am unfamiliar with most Heli's but need to ask. In this heli is it possible to disengage the blades from the gearbox? I believe engine to gearbox yes but gearbox to rotars?. If not then failure of the gerabox and ensuing pile up of gears would bring rotars to a stop or in the event of a rapid stop even seperation of head and or blades right? Jusk asking.

You are correct. Engine to gearbox there is a "sprauge clutch" (varies on type) so if power from engine(s) is lost the rotor and gearbox will continue to rotate to facilitate autorotation. On a multi engine machine the failed/shutdown engine will disengage from clutch and remaining engine assumes load.

Failiure in gearbox would certainly have a negative impact on rotor rpm. Definatly a possibility of sudden stoppage of rotor and the associated torque could very well result in seperation/severe damage.

PS.....just want to make clear nothing above is intended to be associated with the recent accident. Only for information in response to Muskeg's post.

[SeptRepair]

I was emailed this link today, thought I would share.
http://www.tsb.gc.ca/eng/medias-media/p ... 9a0016.asp

[2milefinal]

OLIVER MOORE AND PETER CHENEY
From Thursday's Globe and Mail
March 26, 2009 at 5:08 AM EDT
An order to replace a type of titanium fitting on the gearboxes of all Sikorsky S-92 helicopters has prompted intense debate among professional pilots over what to do in the kind of situation that led to a deadly crash this month off Newfoundland.

The U.S. Federal Aviation Administration issued a directive on Tuesday that a type of titanium fitting found broken in the wreckage of the Cougar Helicopters Inc. crash must be replaced on all Sikorsky S-92 helicopters worldwide, warning that the part's failure could result in "loss of control."

The Emergency Airworthiness Directive grounded all S-92s with gearbox filter assemblies that are mounted using titanium studs. The order was effective immediately, and the helicopters can fly again only after these parts are replaced with steel studs.

"We are issuing this Emergency AD to prevent failure of a stud which could result in rapid loss of oil, failure of the main gearbox, and subsequent loss of control of the helicopter," the FAA stated.


Paul Jackson, a spokesman for Sikorsky, said last night that this sequence of events was not the inevitable result of stud failure and is "a very, very remote possibility." He could not comment, he said, on the investigation into the Cougar crash, but did say that the titanium studs have been replaced on more than two-thirds of the S-92 copters worldwide using material the company provided.

The March 12 crash, which came after the crew reported an oil pressure problem with the main gearbox, killed 17 people during a routine run to offshore oil platforms. One person survived.

Since the accident, professional helicopter pilots have debated the best response to a warning about oil pressure in the main gearbox. Although manufacturers generally recommend landing as soon as possible, some pilots noted that it can sometimes be safer to extend the flight slightly to reach a better landing spot.

Several noted cases in which all aboard had survived because the pilot flew toward land at slow speed and low altitude instead of ditching in the ocean: "If in every one of those cases the pilots had ditched, with the probable 20 per cent loss of life, how many hundreds of pilots and passengers would have perished as a result?" one pilot asked on a helicopter forum.

Another argued that an immediate landing is the best choice: "This accident has just proved that once oil pressure is lost, the gearbox will not stay together long enough to descend from 9,000 [feet]."

A probe of the Newfoundland crash is being led by Canada's federal Transportation Safety Board. The TSB, which is planning to update the public this afternoon, has said that it does not know if the studs on Flight 491 were broken during the crash or before. But the FAA, which noted that this was not the first S-92 incident in which these studs were found to have broken, believes it happened before impact.

The FAA directive did not give more information on the earlier incident, which Mr. Jackson said took place in Australia and resulted in no deaths.

Nonetheless, the company issued a notice in January urging replacement of the studs, telling operators of the copter to substitute the parts within a year or 1,250 flight hours.

ENGINEERING: WHERE THE PROBLEM LAY

Investigators probing the March 12 crash of a Sikorsky S-92 helicopter off Newfoundland are focusing on the possibility that an oil filter assembly leak destroyed the aircraft's main gearbox and stopped the rotor blades.

The discovery of a broken titanium stud on the helicopter's main gearbox oil filter appears to draw parallels with a 2008 incident that forced another Sikorsky S-92 to make an emergency landing in western Australia.

Last July, the pilot of the Australian S-92 noticed a warning light indicating that the oil pressure in the main gearbox had fallen to critical levels. The pilot landed the helicopter eight minutes later. There were no injuries. An inspection showed that titanium studs holding the gearbox oil filter assembly in place had broken, allowing oil to leak out.

That incident prompted Sikorsky to issue a service bulletin: On Jan. 28, it advised S-92 operators to replace the titanium studs with steel ones within 1,250 hours of flight time or a year of the alert, whichever came first.

In a helicopter, gearbox lubrication is critical, and most are designed to run for a short time without oil, allowing the pilot to make an emergency landing. Although a helicopter can fly without its engines by executing a manoeuvre called an autorotation, a gearbox seizure is catastrophic - the rotor blades stop, making it impossible to fly.

Peter Cheney

Caution in the skies

The U.S. Federal Aviation Administration has grounded all Sikorsky S-92s until a key repair is made.

FAA EMERGENCY AIR WORTHINESS DIRECTIVE

"This Emergency Airworthiness Directive is prompted by the failure of 2 main gearbox filter bowl assembly mounting studs that were found broken during a fatal accident investigation in Canada. Prior to the accident, the manufacturer was investigating a July 2008 incident that also involved broken studs. In both cases, the broken studs resulted in rapid loss of oil. The failures have been tied to fretting and galling of the original titanium studs; therefore, we are requiring the removal of all titanium studs and replacement with steel studs."

Two titanium studs break causing rapid loss of oil

Flight 491's path, March 12, 2009

The pilot of Cougar's Sikorsky S-92 issued a mayday and turned back to make a landing before the aircraft crashed.

9:21 a.m. - 2,600 ft.

9:31 a.m. - 8,800 ft.

9:32 a.m. - 9,000 ft.

9:44 a.m. - 9,000 ft.

9:45 a.m. - 8,800 ft.

9:46 a.m. - 7,100 ft.

9:50 a.m. - 1,700 ft.

9:51 a.m. - 900 ft.

9:54 a.m. - 800 ft.

9:55 a.m. - 300 ft.

The helicopter sank about 90 km off Newfoundland's coast.

NINIAN CARTER, TONIA COWAN AND PETER CHENEY/THE GLOBE AND MAIL 66 SOURCE: FLIGHTAWARE.COM

...sorry cant seem to get the link to work


edit:got it
http://www.theglobeandmail.com/servlet/ ... ional/home

[2R]

Would they have made the oil rig if they had not turned around ?
Would a controlled water landing closer to the oil rig allowed the standby vessels or other helio's to rescue the people ?

Just my two questions from someone with several hundred offshore helio trips in the north sea.

[carholme]

2R;

If you read page one of this thread, you will see the distance to the rig. The remainder is self explanatory, I hope.


carholme

[Widow]

Mounting studs failed in N.L. chopper's flight: Safety board
By Ken Meaney, Canwest News ServiceMarch 26, 2009 1:05 PM


The Transportation Safety Board confirmed Thursday that titanium mounting studs in the gearbox of a helicopter that crashed March 12 off Newfoundland broke in flight leading to a catastrophic loss of oil pressure and causing the aircraft to fall out of the sky.

"I can safely say now that the studs broke in flight and the loss of oil pressure was a result of that," lead investigator Mike Cunningham said at a news conference in St. John's, N.L. "We cannot find any anomaly that would account for that."

Cunningham said, however, further analysis is needed to say how and why the stud broke.

The crash, some 55 kilometres southeast of St. John's claimed 17 lives and left only one survivor — Robert Decker, an ice monitor on one of Newfoundland's three oil platforms — who is recovering in hospital in St. John's.

Since the accident the U.S. Federal Aviation Administration issued an emergency directive that effectively grounded helicopters such as the one involved in the Newfoundland crash — a Sikorsky S-92A — until the mounting studs are replaced with steel studs.

Cunningham said that has been done with nearly three-quarters of the aircraft operating world wide and the fleet has begun to return to operations.

The main gear box that is the focus of the investigation has been sent to Sikorsky in Connecticut for further examination.

Cunningham clarified his earlier conjecture that the Sikorsky crashed nose first. He said further analysis of the wreckage in a hangar at the airport in St. John's showed the helicopter actually slammed into the water belly first after a high rate of descent.

He also gave a timeline of events leading to the crash.

The helicopter left St. John's to carry workers to two offshore oil platforms at 9:18 a.m. local time and was flying at about 2,745 metres 27 minutes later when the flight data recorder showed a rapid loss of oil pressure in the gear box. Cunningham said the crew issued a mayday and began descending to 243 m, advising they were returning to St. John's. Two minutes later, there was zero oil pressure in the gearbox.

At 9:54 a.m local time, there was a power interruption in the flight data recorder and cockpit voice recorder and both inexplicably shut off.

A minute later, the crew radioed they were preparing to ditch.

A Provincial Airlines plane flew over the crash site at 10:12 a.m., spotting two people in orange immersion suits in the water. A rescue helicopter reached the pair 43 minutes later, recovering Decker and the body of Allison Maher.

Cunningham said the helicopter broke apart in sections, with all but the tail boom found close together. The boom was found 20 metres away from the rest of the wreck.

He said the investigation is in its early stages and many questions about the accident have not yet been answered.

"There is quite lengthy and detailed work yet to do," he said.

With files from The St. John's Telegram
© Copyright (c) Canwest News Service

http://www.montrealgazette.com/Mounting ... story.html