BA 2276 777 Uncontained Engine Failure and fire at Las Vegas


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The things that come to mind concerning the British Airways 777 that caught fire as it was about to take off from Las Vegas for London on September 8, 2015 are the passengers standing nearby, with many carrying large items of luggage,   and the fact that the UK newspapers referred to the captain, who was possibly making his last flight before duly retiring, as a hero. In fact, the just published final NTSB report shows that it was not that simple.

Firstly, it again seems unbelievable that a report into an accident with the aircraft available for study and any debris retrieved from the runway should take so long–until one remembers the same was true for the one into the precursor to the Southwest

A key point was that the aircraft was only half full and therefore passengers passengers bring their luggage did much affect the fortunate outcome.

 

 

 

 

The NTSB report can be found by clicking HERE
Passengers with their luggage.

 

According to the NTSB report, the captain, who was the pilot flying PF, quickly rejected the takeoff  at about 77 knots, well before V1, the takeoff decision speed was 149 knots for the flight. The start of the rejected takeoff maneuver occurred 2 seconds after the “bang” sound, and the airplane came to a stop 13 seconds after the rejected takeoff maneuver began. Thus, the captain made a timely decision to reject the takeoff and performed the maneuver in accordance with company training and procedures.

 

“While the airplane was decelerating to a stop, the fire warning bell sounded. When the airplane came to stop, the captain called for the engine fire checklist. The third item on the checklist was to move the fuel control switch on the affected side (in this case, the left side) to the cutoff position, which shuts down the respective engine. The spar valve terminates fuel flow to an engine after it is shut down. Flight data recorder (FDR) data showed that about 28 seconds elapsed between the start of the engine failure and the time of the spar valve closure, and Boeing estimated that about 97 gallons of fuel had spilled onto the runway during this time. FDR data also showed that 22 seconds elapsed between the time that the captain initially called for the engine fire checklist and the time of the spar valve closure. (Thirteen seconds had elapsed between the time that the captain repeated his call for the engine fire checklist and the time of the spar valve closure.) If the left engine had been shut down sooner, there would have been less fuel on the runway to feed the fire.

The flight crew informed the passengers and flight attendants to remain seated and await further instruction, which was consistent with the flight crew’s training and procedures if an evacuation was not going to immediately occur. The cabin crew reinforced the flight crew’s expectation by instructing passengers to remain seated. As part of the flight crew’s evaluation of the situation, the relief pilot left the cockpit and entered the forward cabin so that he could look outside a window. Before the relief pilot returned, the CVR recorded the captain’s statements indicating that the airplane should be evacuated. The relief pilot returned to the cockpit shortly afterward and informed the captain of the need to evacuate on the right side of the airplane because of the fire. The captain then commanded the evacuation, and a flight crewmember activated the evacuation alarm.

When the relief pilot went into the cabin to assess the situation outside of the airplane, a flight attendant told him that she had been trying to call the flight crew. The CVR recorded a sound similar to an interphone call from the cabin to the flight deck, but the flight crewmembers most likely did not answer the call because they were focused on securing the left engine and deciding whether to evacuate.

After the captain’s evacuation command, the flight attendants assessed their areas and opened the doors that they deemed usable. Five of the eight door exits were initially blocked by flight attendants, which was appropriate given the hazards associated with the smoke, fire, and unusual attitude of two slides. A sixth door, which was initially opened, was blocked once a flight attendant saw flames on the runway, which was also appropriate. Although only two of the eight door exits were used throughout the evacuation, the passengers and crewmembers were able to evacuate before smoke and fire encroached the fuselage.

The captain commanded the evacuation (step three in the evacuation checklist) before calling for the evacuation checklist and performing the first two steps in the checklist. Step two of the evacuation checklist instructs the captain to shut down both engines. The left engine was shut down as part of the engine fire checklist, but the right engine continued operating for about 43 seconds after the captain’s evacuation command. The unusual attitude of two slides (the 3R and 4R slides) resulted from the jet blast coming from the right engine while it was operating.

The captain did not use the QRH to read and do his evacuation checklist items. The right engine was shut down after the relief pilot noticed EICAS indications showing that the engine was still running. Also, the captain’s call for the evacuation checklist occurred after the relief pilot stated that the checklist needed to be performed. (The first officer had stated, just before the relief pilot, “we haven’t done the engine checklist,” but he most likely meant the evacuation checklist.) Because the captain did not follow standard procedures, his call for the evacuation checklist and the shutdown of the right engine were delayed.

British Airways’ engine fire checklist, which was based on the Boeing 777 engine fire checklist, did not differentiate between an engine fire occurring on the ground or during flight. The third step of the checklist instructed the flight crew to cut off the fuel control switch on the affected side to shut down that engine. However, for an engine fire on the ground, the checklist did not include a step to shut down the unaffected engine or indicate that some steps did not apply. If the engine fire checklist had specifically addressed fires during ground operations, the flight crew could have secured the right engine in a timelier manner and decided to evacuate sooner. In February 2018, as part of its final report on the American Airlines flight 383 investigation, the NTSB issued two related safety recommendations, A-18-6 and A-18-10, to address this issue.

The relief pilot relayed pertinent information to the captain and first officer as the emergency unfolded. The relief pilot pointed out the smoke to the flight crew and volunteered to assess the situation outside the airplane from a window in the cabin. After returning to the cabin and reporting his assessment, the relief pilot indicated that the airplane was still on fire on the left side, and the captain commanded the evacuation. The relief pilot also noticed that the right engine was still running and indicated that it needed to be shut down. Thus, the relief pilot played an important role in ensuring the safety of the airplane occupants.

During a group debriefing by the Air Accidents Investigation Branch, the flight attendants stated that some passengers evacuated with carry-on baggage; however, the flight attendants thought that carry-on baggage retrieval did not slow the evacuation. They thought that most passengers who retrieved baggage did so after the airplane came to a stop and before the evacuation was commanded and that the flight attendants’ assertive commands limited further retrieval. The flight attendants at the two most-used exits (doors 1R and 4L) recalled seeing very little baggage at their exits, and neither cited carry-on baggage as a problem. However, the NTSB notes that the accident airplane was only 55% full.

Although not a factor in this evacuation, the NTSB remains concerned about the safety issues resulting from passengers evacuating with carry-on baggage, which could potentially slow the egress of passengers and block an exit during an emergency. The NTSB previously addressed carry-on baggage in a June 2000 safety study on evacuations of commercial airplanes and issued Safety Recommendation A-18-9 in February 2018 as part of its final report on the American Airlines flight 383 investigation.

 

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The failure of the left engine high-pressure compressor (HPC) stage 8-10 spool, which caused the main fuel supply line to become detached from the engine main fuel pump and release fuel, resulting in a fire on the left side of the airplane. The HPC stage 8-10 spool failed due to a sustained-peak low-cycle fatigue crack that initiated in the web of the stage 8 disk; the cause of the crack initiation could not be identified by physical inspection and stress and lifing analysis. Contributing to this accident was the lack of inspection procedures for the stage 8 disk web.

The press saw this as an example of great airmanship. However with one engine left running, thus delaying the evacuation and with its blast contorting one or more slides, the outcome could well have been less favorable had the aircraft been full with luggage impeding evacuation.

 

Uncontained Engine Disintegration/Southwest

In Air Crashes and Miracle Landings  we describe two “catastrophic” cases where the shrapnel from the engine struck vital parts, even in more than a hundred places, and  by dint of great airmanship  the aircraft was brought back with many and all surviving. In the case of Southwest 1380 unfortunately it was a passenger who suffered.

UA232

The first of the two incidents was the “Uncontrollable” DC-10’s Miracle Landing at Sioux City.  United Airlines Flight 232, July 19, 1989.

The engine that disintegrated  was in the tail of the jumbo trijet. In that case, rather than  single blade as in South west 1380 that might have been retained by the protective casing, it was a blade-retaining disk further down in the engine that shattered with a with a large heavy piece penetrating the fuselage and slicing through the triplicate (for safety on the belt-and-braces principle) hydraulic control lines for the rudder and elevators in the tail.

With no rudder of ailerons, and no hydraulic pressure to operate the ailerons the aircraft was theoretically uncontrollable. However, with the help of an off-duty captain who had  been sitting in First Class and who on realizing something was wrong had offered his services, they were able to maneuver the aircraft by adjusting the power of the two engine in pods under the wings. This was facilitated by the fact that they were very low-slung to balance the third engine (the broken one) high up in the tail. However, they were only able to make crude adjustments and, unlike conventional controls, any action (increase or decrease of power one one side or the other) would take several or more seconds to have an effect.

They managed to come in with an extremely high rate of descent into Sioux City Airport but with a wing dropping and correction in time impossible it snagged the ground and crumpled . The aircraft cartwheeled and broke into five piece. 

 Incredibly, 185 people out of 296 survived, making a death toll of 111. That so many survived was to some extent due to the sterling efforts of the cabin crew and their rigorous training in a simulator, which made a crash landing and fire seem real.
Even so, their contribution would have probably been in vain, supposing they were even still alive, had not the high rate of descent and the 215 + 10 knot ground speed been absorbed in some manner. This is a prime example of the fact mentioned in this book’s preface that the more horrendous-looking crashes can be the most survivable, due to the fracturing and crumpling absorbing the shock.

It is a remarkable tale, and must rank as one of the true aviation “miracles.” 

QF32

The other incident we describe in detail in the book is Qantas Flight QF 32, on November 4, 2010, where the engine on a double-decker Airbus A380 superjumbo disintegrated with shrapnel hitting it in some hundred places but fortunately not penetrating the passenger cabin. With almost 95% of systems compromised and fuel leaking from the wing the pilots flew around for an hour solving as many problems as possible before landing faster than usual with a dangerously overweight aircraft and hardly any runway to spare.

It is another example of great airmanship.

 

 Southwest 1380

The pilot (and copilot) have been praised. Interestingly they cane in faster than usual at 170 knots, apparently because of the limited flap. However, when unsure of the state of the aircraft extra speed and one at which the aircraft is known to be OK is the  safest option. One only too well remembers the DC-10 in the photo below that flipped over and crashed when the loss (falling off) of an engine caused the slats on tha twing to retract. The pilots had followed the rule-book and slowed, when had they stayed at their speed the wing would not have stalled and the aircraft would have been flyable. (The idea behind slowing down was to avoid the theoretic danger of a damaged aircraft breaking up.)

 

 

 

Surprising tweet from someone who indicated an agenda

There have been many tweets praising the captain of Southwest 1380.  Yet, there was one admonishing her because her voice in her verbal exchanges with ATC did not indicate any compassion for the victim(s). No mention of the fact that, her essential job done, she came to give verbal support to the traumatised passengers. Could it have been fake news to bring someone with that agenda into disrepute?

 

 

Southwest Incident, Would More Slowly Rotating GTF Fan be safer?

It would be interesting to know whether a geared turbofan engine might be safer than the conventional one as regards the type of incident sadly suffered by Southwest Airlines. A fan rotating more slowly might be less likely to lose a blade and the centrifugal force being less might mean the casing might retain it should it fail.

One thing that is surprising is the time the NTSB will take to draw definitive conclusions when they can already see the place where the blade fractured, unlike in crashes where thousands of pieces have to be recovered to find the cause.