US, UK investigators seek 777 engine redesign to stop repeat of London jet crash
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Saturday, March 14, 2009
Investigators with the National Transportation Safety Board in the United States have issued an ‘urgent safety recommendation’ in connection to their role alongside the United Kingdom’s Air Accidents Investigation Branch in investigating loss of power in Rolls-Royce engines on Boeing 777s, with the AAIB following suit. One of them resulted in British Airways Flight 38 crashing short of the runway at London’s Heathrow Airport last year. The NTSB and the AAIB want Rolls-Royce to redesign the engines.
Both events occurred on Boeing 777-200ER airplanes powered by Rolls-Royce RB211 Trent 800 Series engines. On January 17, 2008 British Airways Flight 38 experienced a dual engine rollback (reduction of engine power) on final approach to Heathrow and crashed, leaving one passenger seriously injured, eight passengers and four of the flight crew with minor injuries and the airplane written off.
The second event occurred on November 26, 2008, when a Delta Air Lines Boeing 777 experienced a single engine rollback during cruise flight over Montana, United States while en route from Shanghai to Atlanta. Normal operations resumed after the flight crew followed Boeing’s published procedure to recover engine performance and the airplane landed safely in Atlanta.
Boeing has already developed new procedures after the crash to prevent ice from building up within their 777 fuel systems after it became apparent that icing may have been a factor, and it was some of these that the Delta flight crew had followed. Boeing modified these further after the Delta incident. As part of the recent releases by the NTSB and AAIB it has become apparent that investigators from both bodies, which are collaborating, have found ice buildup in the fuel system caused both rollbacks.
In both cases a build-up of ice (from water normally present in all jet fuel) developed on a component called the fuel/oil heat exchanger. This restricted the flow of fuel to the engine, resulting in the uncommanded engine rollback. Investigators initially struggled to produce enough ice under test conditions but have now found that at high concentration, fuel can form ice at very low temperatures in enough quantity to seriously restrict fuel flow, according to a new interim report by the AAIB. This does not occur when fuel demand is lower, as the hot oil then becomes sufficient to entirely melt the ice. The British jet experienced very low temperatures over Siberia.
The vigorous tests are thought to be the first of their kind. They have also confirmed that while ice may have formed elsewhere in the airliner’s fuel system fuel was probably not restricted at any other location. Instead, it is thought ‘soft’ ice formed in the pipes and then broke off, travelling to the fuel/oil heat exchanger and restricting it.
The NTSB has now revealed that they have advised Rolls-Royce to redesign the fuel/oil heat exchanger, and Rolls-Royce have stated that they are indeed working on a replacement part that will be available within twelve months. The AAIB advised Boeing and Rolls-Royce to jointly review the problem across the fuel system, and both companies responded that they ‘accepted’ this recommendation and repeated that a replacement part was being developed.
Both the NTSB and the AAIB also sent letters to the US Federal Aviation Administration and the European Aviation Safety Agency requesting the installment of the modified component be mandatory. The NTSB suggested this should be either the next maintenance check or within six months. There are 220 Boeing 777-200s – the only type using the affected engine – with Trent 800 series engines.
The fuel/oil heat exchanger is a dual purpose part designed to simultaneously melt fuel ice and cool down engine oil.
The AAIB further noted that it is unclear weather other aircraft designs are at risk, and advised the FAA and EASA to look into increased use of de-icing additives and investigate both the accumulation and sudden movement of ice in aircraft fuel systems and the actual formation of ice in the fuel itself.
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By Mark Freeman
Hemorrhoid or anal fissure. Either one is a very painful condition. Some people who have anal fissures think their pain is caused by hemorrhoids and some who have hemorrhoids mistakenly think they suffer from an anal fissue. Here we’ll try to explain the difference.
An anal fissure is, simply stated, a small tear or cut in the lining of the anus. Anal fissures are generally caused by straining while on the toilet or by constipation. Sometime fissures are related to severe bouts of diarrhea. Fissures can be quite painful, especially during a bowel movement when the fissure is stretched. There will be red blood streaking the stool if you have a fissure.
[youtube]http://www.youtube.com/watch?v=0uwx64YaxSk[/youtube]
Over 90% of fissures will heal without surgery. Recommendations to help prevent recurrence are increasing the fiber intake in your diet. This can be best achieved by taking an over the counter fiber supplement. Drink plenty of water to help keep your stools soft. Some take stool softeners, but do not take them for a longer period of time than is suggested by the manufacturer. Warm sitz baths can help ease the pain. Sit in a few inches of warm water for 15 minutes two to three times a day. When you wipe, use a cotton ball or pad soaked in witch hazel. You can buy pre moistened wipes in your drug store. Some who suffer with fissures are prescribed topical cortisone creams. Tylenol and Ibuprofen can help ease the pain.
Hemorrhoids are a very common medical ailment that affect both men and women. A hemorrhoid is an enlarged or swollen anal vein. As with anal fissures, hemorrhoids develop due to bad bathroom habits, such as sitting on the toilet for prolonged periods or straining. You will notice bright red blood with hemorrhoids. You may suffer from internal or external hemorrhoids. Generally internal hemorrhoids, which appear higher up in the anus are not painful, and only cause bleeding. It’s when an internal hemorrhoid prolapses, or drops outside of the anus and becomes what is know as an external hemorrhoid that it becomes painful and problematic.
Like anal fissures, hemorrhoid symptoms can be helped by sitz baths, wiping with cotton soaked with witch hazel, taking stool softeners, drinking more water, and increasing the fiber in your diet with a fiber supplement. There are numerous over the counter medications that can help relieve symptoms.
Please remember, not all rectal bleeding is due to hemorrhoids and fissures. If you experience any rectal bleeding it should be checked immediately by a physician.
About the Author: This article courtesy of
hemorrhoid-problems.com
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Seventeen injured after coach overturns near Oxford, England
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Monday, December 13, 2010
At least seventeen people were admitted to an Oxford hospital after a coach, operated by the Oxford Tube service, overturned while exiting the M40 motorway near Thame, Saturday evening. There were no other vehicles involved according to Thames Valley Police.
The incident took place at around 2300 GMT Saturday night at junction seven of the M40 near Milton Common, when a coach, belonging to the Oxford Tube service, overturned on a slip road. A police spokesperson stated “The exit slip at junction seven was closed, as well as the A329 in both directions either side of the M40. The coach is in the process of being recovered from the motorway.” The motorway itself remained open.
Sergeant Steve Blackburn of Thames Valley Police stated that “The vast majority [of passengers] were walking wounded or not injured at all and were released either at the scene or shortly after receiving some treatment.”
John Nixon from Oxfordshire Fire and Rescue noted that the coach was lying on its side on an embankment, stating that his crews’ priority had been to stabilise the coach. He added, “There were people laid on the side of the embankment, on the road, covered in space-type blankets to keep them warm”
Although there were no fatalities, five of the injured required surgery, which was undertaken at Oxford’s John Radcliffe hospital. Of the other admissions, a number were discharged by Sunday morning.
A spokesperson for the Oxford Tube was quoted by the BBC as stating that, “Safety is our absolute priority and our immediate thoughts are with those who have been injured in the accident.” They added, “We will be carrying out our own internal investigation and assisting the police in any way that we can with their inquiries into the accident.”
Police have already begun an investigation into the cause of the accident and have requested witnesses come forward.
| Anyone who witnessed the incident is asked to contact Three Mile Cross roads policing unit via Thames Valley Police’s 24-hour Enquiry Centre on 08458 505 505 |
