7 September 2010; Alrosa Mirny Air Enterprise; Tu154M; RA-85684; flight 514, Izhma, Russia: The aircraft was on a scheduled domestic flight from Udachny to Moscow, Russia. While en route at about FL347 near over Usinsk, Russia, the aircraft experienced a complete electrical failure that resulted in a loss of navigational equipment, fuel pumps, and flaps.
Effects of loss of electrical power The Tupolev Tu154 uses the electric pumps that move the fuel from wing and center section fuel tanks into an engine feed tank. Inoperative fuel pumps left the crew with just the usable fuel in the engine feed tank, which provided about 30 minutes of flying time. Although the flaps are hydraulically driven, the switches that control the flaps are electrically driven, preventing the crew from using flaps during any landing attempt.
Successful emergency landingThe crew chose to land the airplane at an abandoned runway near the town of Izhma. The runway is about 4,000 feet (1,220 meters) long, and the aircraft overran the runway by about 150-200 meters, plowing through trees and other vegetation, and coming to rest in soft ground. According to a report in RT.com, one of the passengers described the aircraft as “cutting the tree tops like a lawnmower.” None of the nine crew members or 72 passengers were injured.
Comic relief and plane crashes When planes crash and everyone walks away to fly again, the world breaths a sigh of relief. When there is a happy ending like with this Alrosa accident, one of the ways that the average person responds is with a bit of humor. The following cartoon depicting Mother Nature's reaction to the impending emergency landing was published by the TV-Novosti site RT.com.
At SAE's recent 2009 AeroTech Congress and Exhibition, which was held in Seattle earlier this month, a Boeing fuels systems expert provided an update on the investigation of the January 2008 crash of a British Airways 777-200 (Flight 38, G-YMMM).
In the January 2008 crash, the flight from Beijing to London was routine until the the aircraft was on final approach, when both engines had an uncommanded power reduction, or engine rollback, which caused the plane to land short of the runway. Although the aircraft was seriously damaged, only one of the 136 passengers was seriously injured, and there were no serious injuries among the 16 crew members.
The Air Accidents Investigation Branch (AAIB) of the UK is heading the investigation, and has released several interim reports, most recently in March 2009. In that report, a buildup of ice in the fuel system was identified as a likely cause of the uncommanded power reduction.
The most revealing insights provided by Boeing was that this kind of fuel icing problem was identified in the 1960s with the B-52, and the lessons learned from that experience led to changes in fuel system design that largely eliminated the problem. The January 2008 British Airways event, and a subsequent November 2008 rollback event involving a single engine on a Delta 777, led to a very thorough review of both the 777 fuel system and to the dynamics of fuel icing.
Among the more surprising findings from fuel system tests (which included system components from the accident airplane) was that in some situations, 777s flying with Rolls Royce engines can have ice form in the fuel system, and that ice could in turn block fuel flow at the fuel oil heat exchanger.
It was a difficult problem to study because ice formation was somewhat unpredictable in that tests similar environmental and fuel flow conditions may have produced significant amounts of ice in one test, and very little or no ice in another test.
In spite of the difficulty Boeing had in recreating the conditions that could cause icing, solving the problem was relatively easy. Changes in the fuel oil heat exchanger, plus changes in flight crew procedures, will be enough to prevent these kids of icing events in the future.
AAIB is still investigating this accident, and when the final report is released, AirSafe.com will review the report and summarize the findings in the AirSafe.com News.
For more details on this investigation, including videos summarizing previous Interim reports from the AAIB, visit 777.airsafe.org.
In early March 2009, the AAIB released findings from the investigation of the January 2008 British Airways 777 accident that point to ice buildup in the fuel system as the key factor in the crash in London. On March 11th, 2009, the NTSB called for a redesign of the fuel system, and for the affected aircraft to have those changes installed within six months after the redesign is complete. Watch or listen to the AirSafe.com report on these updates below, or read the transcript.
Recent findings from the AAIB accident investigation point to ice buildup in the fuel system as the key factor in the January 2008 crash of a British Airways 777 in London. On March 11th, 2009, the NTSB called for a redesign of the fuel system, and for the affected aircraft to have those changes installed within six months after the redesign is complete.
You can hear this information in the podcast here or at at podcast.AirSafe.org
In the January 2008 crash, the flight from Beijing to London was routine until the the aircraft was on final approach, when both engines had an uncommanded power reduction, or engine rollback, which caused the plane to land short of the runway. Although the aircraft was seriously damaged, only one of the 136 passengers was seriously injured, and there were no serious injuries among the 16 crew members.
The Air Accidents Investigation Branch in the UK headed the investigation, with the help of several other organizations, including the aircraft manufacturer Boeing, the engine manufacturer Rolls Royce, and British Airways.
The series of updates and interim reports from the AAIB, the most recent of which was released in early March 2009, revealed that the likely cause of the dual engine rollback was ice blockage in a critical fuel system component that led to a reduction of fuel flow to the engine.
These findings didn't come easily. The AAIB focused its efforts on the fuel system because of the unusual conditions of the accident flight. That flight was exposed to rather cold atmospheric conditions, so cold that the crew changed altitudes at one point to fly through warmer air.
The AAIB reviewed the minimum fuel temperature data from over 141,000 777 flights. About 13,000 of these flights were on aircraft operating with the Rolls Royce Trent 800 series engine, the same kind as on the accident aircraft. Of those 13,000 flights, only 118 had fuel temperatures at takeoff that were at or below the takeoff fuel temperature of the accident flight, and during the approach phase, only 70 had fuel temperatures that were as low or lower than the fuel temperature on the accident flight.
The two most likely accident scenarios that were investigated by the AAIB both involved ice formation within the fuel system, leading to a reduction of fuel flow. This ice formation was possible because the aircraft fuel did contain some water. This kind of contamination is normal, and in fact the fuel from the accident aircraft was tested, and found to be in compliance with the appropriate fuel specifications.
After an extensive analysis of the fuel system, the AAIB concluded that the most likely scenario for the engine rollback was that ice formed in the fuel pipes within the main fuel tank, and that during the latter part of the approach phase of the flight, factors such as turbulence, aircraft pitch changes, and increasing temperatures could have contributed to the sudden release of accumulated ice into the fuel feed system of both engines. This ice would have restricted the fuel flow through a component called the fuel oil heat exchanger and would have led to the engine rollbacks.
The AAIB recommended that Boeing and Rolls Royce review the aircraft and engine fuel system design, and make changes that would prevent ice from restricting fuel flow through the fuel oil heat exchanger.
In the US, the National Transportation Safety Board went further, recommending that within six months of completing the redesign, that it be incorporated in all 777 aircraft using the Trent 800 engines. Some of the airlines that fly Trent 800 equipped triple sevens include Air New Zealand, American Airlines, British Airways, Cathay Pacific, Delta Airlines, El Al, Emirates, Kenya Airways, Malaysia Airlines, Singapore Airlines, and Thai Airways. There are about 220 such aircraft currently in service.
The NTSB's recommendations were influenced by a second 777 rollback event. On November 26, 2008, a Delta 777, powered by two Trent 800 series engines, experienced a single-engine rollback while in cruise on a flight from Shanghai to Atlanta. The crew was able to address the issue and continued the flight without incident. Later analysis indicated that there was a blockage of the fuel oil heat exchanger on that engine that was likely due to ice accumulation. Although the engine rollbacks on the British Airways accident aircraft and the Delta Airlines incident aircraft occurred during different phases of flight, the fuel temperatures at the time of the rollbacks were about equal.
Taken together, these developments are good news for the aviation community, especially passengers and crews flying on 777s equipped with Trent 800 engines. The investigative authorities have determined the likely cause of the event, the changes to the fuel system that are needed are well understood, and the engine and aircraft manufacturers are well on their way to developing solutions that will prevent similar occurrences in the future.
For more on this investigation, or for information about aviation safety or aviation security issues, please visit 777.AirSafe.org.
This is the fourth update from AirSafe.com on the ongoing investigation into the accident at London's Heathrow Airport involving a British Airways 777. This update is based on information released by the AAIB the week of 11 May 2008.
This article is based on the AirSafe.com podcast published on 20 May 2008. The podcast, available at http:/podcast.airsafe.org, presents the highlights of the most recent update from the Air Accidents Investigation Branch concerning the status of the investigation. There is a brief review of the details of the accident, followed by a discussion of the new information provided by the AAIB report, and an analysis of the progress of the investigation.
The accident aircraft was a scheduled international flight from Beijing, China to London, England, and the flight was routine until about two miles from touchdown. The engines would not respond to commands to increase thrust, and as a result the aircraft touched down about 1000 feet short of the runway. There was a significant fuel leak, but no post-crash fire. All 136 passengers and 16 crew members were able to successfully evacuate the aircraft, and the most serious injury was a broken leg suffered by one passenger.
The three previous AAIB updates in January and February 2008 provided detailed information about the flight, including the state of the fuel and fuel systems, and the condition of the engines and their associated control systems. You'll find details about the previous updates, as well as links to previous podcasts describing the accident sequence, at http://777.airsafe.org.
For the last several months, the AAIB has focused on the fuel and fuel systems of the aircraft. Extensive examination of the aircraft and detailed analysis of information from the flight data recorder and other onboard recording systems have revealed no evidence of an aircraft or engine control system malfunction.
The fuel was extensively tested, and showed no evidence of contamination or excessive water content. Although the aircraft had experienced very cold temperatures, the fuel temperature remained well above freezing. Detailed examination of the fuel system revealed a loose connection in one of the fuel lines as well as the presence of small pieces of debris, but these conditions led to no unusual deterioration or physical blockages.
The ongoing investigation has also found no evidence that a wake vortex encounter, bird strike, engine icing, or electromagnetic interference played a role in the accident. The focus of the investigation continues to be the fuel system and the engines, with the goal of understanding why neither engine responded to demands for increased power even though all of the engine control functions operated normally.
Under the direction of the AAIB, the engine manufacturer Rolls-Royce and the aircraft manufacturer Boeing are conducting further tests on the engines and fuel system with the goal of replicating the fuel system performance seen in the accident flight. Additional work is being conducted to gain a more complete understanding of the dynamics of the fuel as it flows from the tank to the engine.
No individual parameter associated with the accident flight was outside of previous operating experience. However, the AAIB is using a data analysis team to review data from a large sample of flights on similar aircraft to see if there was a combination of parameters that was outside of previous experience.
Unlike the last AAIB interim report issued in February 2008, this report did not contain any recommended operational changes for the 777.
I'd like to take a moment to share my opinion about the progress of this investigation. This crash investigation has not yet come up with an explanation for what happened. This is in spite of having a largely intact aircraft, a large volume of data from the accident aircraft and comparison data from similar flights, and the combined resources the engine manufacturer, the aircraft manufacturer, and the British government. This probably means that if the AAIB does come up with an explanation for why the accident happened, the explanation will include a combination of circumstances that had not been previously anticipated by aircraft designers or aircraft operators.
The suggestions made in previous AirSafe.com podcasts about how to evaluate what's being published about this investigation are still valid .
If you're interested in following the investigation online or in the news media, keep in mind that prior to the completion of the investigation by the AAIB, anyone outside of the investigation, including aviation safety experts and the largest news media organizations, will have access only to a fraction of the relevant information.
The AAIB will likely provide several more updates prior to publishing a final report, and these updates represent the most authoritative sources of information about the ongoing investigation.
7 September 2010; Alrosa Mirny Air Enterprise; Tu154M; RA-85684; flight 514, Izhma, Russia: The aircraft was on a scheduled domestic flight from Udachny to Moscow, Russia. While en route at about FL347 near over Usinsk, Russia, the aircraft experienced a complete electrical failure that resulted in a loss of navigational equipment, fuel pumps, and flaps. 
Successful emergency landingThe crew chose to land the airplane at an abandoned runway near the town of Izhma. The runway is about 4,000 feet (1,220 meters) long, and the aircraft overran the runway by about 150-200 meters, plowing through trees and other vegetation, and coming to rest in soft ground. According to a report in RT.com, one of the passengers described the aircraft as “cutting the tree tops like a lawnmower.” None of the nine crew members or 72 passengers were injured.
