Flight International - January 13, 2015

26 | Flight International | 13-19 January 2015 flightglobal.com

COVER STORY

identify a specific cause for the

lithium-ion battery failure aboard ANA

flight 692, it provides probable caus-

es and has recommendations for

both the US Federal Aviation

Authority and Boeing. “Internal heat

generation in cell six very likely devel-

oped into venting, making it the initi-

ating cell, resulting in cell-to-cell

propagation and subsequent failure

of the main battery,” the report says.

“It is very likely that cell six internal

heat generation and increased inter-

nal pressure caused it to swell, melt

the surrounding insulation material

and contact the brace bar, creating a

grounding path that allowed high cur-

rents to flow through the battery box.

The currents generated arcing inter-

nal to the battery that contributed to

cell-to-cell propagation consequently

destroying the battery.” It adds that

the heat generation in cell six was

“probably” due to a short circuit, but

says “the conclusive mechanism

thereof was not identified”. During

the Yamaguchi Ube-Tokyo flight the

flightcrew received several battery

warnings and smelled fumes in the

cockpit. They made an emergency

landing at Takamatsu, where all 129

passengers and eight crew were

evacuated via the aircraft’s slides.

The ANA incident followed another

lithium-ion battery failure on 11

January 2013, aboard a Japan Air

Lines 787 parked at Boston Logan

International airport. Echoing com-

ments from both the NTSB and

Boeing itself, the JTSB states that

the airframer’s original testing regi-

men for the battery was insufficient,

mainly as it did not adequately simu-

late a realistic operational scenario.

The board recommends that the FAA

instruct manufacturers to test equip-

ment under conditions simulating

actual aircraft configurations, and

review the technical standards for

testing lithium-ion batteries. Boeing

has since redesigned the battery

and its stowage area.

■ The final report into the crash of a

Lion Air Boeing 737-800 into the sea

on short final to land at Denpasar’s

Ngurah Rai International airport on

13 April 2013 has identified several

pilot skill deficits and failures in the

carrier’s emergency response proce-

dures. The National Transportation

Safety Committee (NTSC) report

highlights the failure of the captain

and first officer to communicate ef-

fectively during the approach. The

report also refers to CCTV footage

that shows the bad weather and

poor visibility immediately prior to the

crash that prevented the flightcrew

from seeing the runway. The first of-

ficer, who was flying, mentioned that

the runway was not in sight as the

aircraft descended through 900ft on

final approach after an uneventful

flight from Bandung. Although the

aircraft’s automated systems issued

a “minimum” warning at 550ft, the

crew disengaged the autopilot and

autothrottle and continued the de-

scent manually. At 300ft the cockpit

voice recorder identifies a sound

consistent with rain hitting the wind-

shield. When the 737 had descend-

ed to just 150ft, the captain took

control and the first officer again said

he could not see the runway. After

the enhanced ground proximity warn-

ing system called a 20ft height alert

CONTINUED

ACCIDENT REPORTS PUBLISHED IN LAST SIX MONTHS OF 2014

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Passengers (millions)

0

2

4

6

8

10

12

14

16

1990 1995 2000 2005 2010 2014

2014 PASSENGERS CARRIED PER FATAL ACCIDENT (EXCLUDES ACTS OF VIOLENCE)

SOURCE: Ascend Note: Jet and turboprop aircraft of more than 14 seats

Passengers carried per passenger fatality

Five-year average

Flights (millions)

0.0

0.5

1.0

1.5

2.0

2.5

1990 1995 2000 2005 2010 2014

2014 FLIGHTS PER FATAL ACCIDENT (EXCLUDES ACTS OF VIOLENCE)

SOURCE: Ascend Note: Jet and turboprop aircraft of more than 14 seats or cargo equivalent

Flights per fatal accident

Five-year average

6 million passengers were carried for
every one that was killed in a jet accident,
whereas in 2013 – in which the number of fatal
accidents was higher, but the resulting fatali-
ties much lower – almost 16 million passen-
gers were carried for every one that died (see
graph, right). This measure is useful for deter-
mining how safe commercial aviation is as a
mass public transport system, but it feels rather
artificial to a passenger who, on boarding a
flight, hopes the entire flight will be safe, rather
than taking comfort in the fact that his personal
chance of survival is 6 million-to-one in favour.
There were two accidents in 2014 that oc-
curred in similar circumstances – both were
in tropical latitudes at cruising level, and just
before they disappeared their crews radioed
that they needed to manoeuvre to avoid bad
weather. The first was an Air Algerie/Swiftair
Boeing MD-80 over Mali in July, the second
an AirAsia Airbus A320 over the Java Sea in
December (see accident list). For reasons yet
to be established, neither crew managed to re-
tain control of the aircraft.
It is worthy of note that in recent years the
same circumstances have had a similar result
in two other cases. One was the 1 June 2009

The total in 2014 of 671

fatalities results from the

fact that three of the

accidents involved big jets,

and one a large turboprop

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