Flight International – 11 June 2019

ightglobal.com 11-17 June 2019 | Flight International | 69

PARIS

Safety

Although the fin of AF447 was recovered,
analysis of similar underwater operations
showed that tail debris was retrieved in only
20% of cases, dismantling the rationale of
using the fin to house another fixed flight re-
corder. BEA recommended, in the wake of
AF447’s loss, that ICAO should explore the
implementation of deployable recorders for
commercial air transport aircraft.
The still-unsolved disappearance of Malay-
sia Airlines flight MH370 over the Indian
Ocean in March 2014, nearly five years after
the AF447 accident, lent urgency to this rec-
ommendation. Not only did the Boeing 777’s
deviation from its planned route to Beijing
complicate the search for the crash site, it also
forced investigators to consider whether –
even if the recorders were found – critical in-
formation from the early stage of the flight
would have been overwritten and lost.
ICAO’s subsequent concept of operations
for a Global Aeronautical Distress and Safety
System covered the possibility of automatic
deployable flight recorders, and the organisa-
tion’s Annex 6 for operation of aircraft lists
requirements that must apply to such devices.
These include deploying when the aircraft
structure is significantly deformed or the air-
craft sinks in water. The recorder must deploy
as a single piece, be able to float on water, and
have an integrated emergency locator trans-
mitter. The crew must also be alerted when
the recorder is no longer captive.

CO-OPERATION AGREEMENT
Airbus has started testing a “non-functioning”
deployable recorder on the A350-1000, it
says, two years after it unveiled a co-operation
agreement at the 2017 Paris air show to de-
velop such a device. Under the agreement, US
aerospace specialist L3 Technologies has been
tasked with leading development of a com-
bined cockpit-voice and flight-data recorder,
while the Canadian arm of defence technolo-
gy firm Leonardo DRS is focused on the de-
ployment capability.
Airbus’s project takes the concept of using
the vertical fin as a recorder housing, but
adapts it so that the fin hosts a tray, built into
its internal structure near the root and leading
edge, into which a beacon airfoil unit can be
mounted. This unit contains a recorder mem-
ory module and emergency locator transmit-
ter, along with batteries and a satellite receiv-
er. Its outer surface is flush with the skin of
the fin, with no aerodynamic impact.
The system features a spring-loaded ejec-
tion mechanism that enables the beacon air-
foil unit – and its recorder – to separate from
the fin. L3 says a “portion” of the system is
flying on the A350 testbed, and describes it as
a “non-functional mechanical prototype”.
Flight-testing with fully-functional equip-
ment – specifically a deployable version – is

not expected to take place before the end of

this year or perhaps the first quarter of 2020.

Airbus says this flight-testing will “tentative-

ly” be conducted in parallel on various aircraft

types including the A350, A330, A321LR and

A320. The system is intended primarily for

aircraft operating transoceanic services.

L3 explains that the architecture on an

equipped aircraft will include a single integrat-

ed cockpit-voice and data recorder installed in

the nose, along with a recorder interface unit,

complemented by the deployable module in

the fin. It says this architecture will be standard

on long-range aircraft including the A350,

A330neo and A321LR, and optional on single-

aisle models such as the A320neo.

Airbus had originally encountered resist-

ance to deployable recorders, not least be-

cause earlier concepts had been based on the

use of low-power pyrotechnics or chemical

systems to launch the device.

Its non-pyrotechnic system relies instead

on crash-detection circuits, able to identify

major structural deformation of the airframe

or submersion in water, which electronically

release a spring that pops the beacon airfoil

unit partly out of its housing tray. Pushing a

forward portion of the airfoil unit outward

enables the airstream to prise it from its hous-

ing, rotating it along its aft section and provid-

ing sufficient lift to allow the unit to separate

safely from the fin. This eliminates the need

for a high-power ejection.

Although the unit would not be fitted with

a parachute or other means of deceleration, its

shape is designed to allow stable free-fall at

terminal velocity, well within the limits of

crash recorder survivability.

HYDROSTATIC SENSORS

In the event of an accident on water, hydro-

static sensors would trigger deployment if the

aircraft sinks. The unit is designed to float and

transmit position information. As well as

sending data on the aircraft identification and

location to search and rescue authorities via

the COSPAS-SARSAT network, the unit will

continually update its position using the sat-

ellite receiver. Airbus says the threshold for

deployment will be sufficiently high so that a

hard landing or accidental impact from a vehi-

cle on the ramp would not release the recorder.

L3 says the system is “on schedule” for cer-

tification in the second quarter of 2020, and

Airbus states that the deployable recorder is

“on target” for entry into service in 2021.

A350s entering the final assembly line this

year are starting to receive provisions that

would allow a retrofit of the deployable re-

corder system, says Airbus. Aircraft without

these provisions cannot be retrofitted.

As part of the development programme

L3’s combined voice and data recorder is set

to have 25h capacity, in line with ICAO rec-

ommendations for extended capabilities.

Airbus intends the system to be available to

carriers across its range of aircraft. “Customers

are interested,” it says. L3 adds that “several

customers showed keen interest” in the sys-

tem and “enquired about its availability” dur-

ing the IATA Safety and Flight Operations

conference in April, although it declines to

disclose the identities of potential users. ■

A total of 228 people lost their lives when flight AF447 crashed in the mid-Atlantic

Sebastiao Moreira/EPA/Shutterstock

A350s entering the final

assembly line this year are

starting to receive provisions

that would allow a retrofit of

the deployable recorder