airasia flight qz8501 winds of strong wind shear and...

By AW CHENG WEI

AS THE search focus for theill-fated AirAsia Flight QZ8501shifts to underwater operations, aremotely operated vehicle onboard Singapore’s MV Swift Res-cue was launched for the firsttime at a new location yesterday.

But it did not find anything atthe site, given by Indonesia’ssearch and rescue agency, Basar-nas, at 11.30am, as visibility wasaffected by strong underwater cur-rents.

The location – which the MVSwift Rescue started scanning atabout 3.05pm – is one of five sitesidentified by Basarnas wherethere are parts of the plane underwater.

Flight QZ8501 disappeared onehour into its flight from Surabayato Singapore on Dec 28.

All 162 passengers and crew onboard are presumed dead. Thecause of the crash is as yet un-known.

The call for the submersible ma-chine, which is remotely control-led from its support and rescuevessel, was made after the Indone-sian authorities provided a scan ofthe area, said Major Wee HongTat, deputy officer-commandingof the MV Swift Rescue.

At about 5.55pm, the submersi-

ble, loaded with sensors, lightsand cameras, was lowered intothe water, where it stayed forabout 45 minutes.

However, operators failed to lo-cate any debris with visibility lessthan a metre.

The wind speed was at 10 knots

and the sea state – the degree ofturbulence measured on a scale ofone to 12 – was at two. This wasan improvement from Sunday, so

the vessel was able to cover moreground.

Today marks the eighth day theMV Swift Rescue will be at sea.

It is one of three Singaporeanvessels – the other two being RSSPersistence and RSS Kallang – cur-rently searching the Java Sea forparts of the plane. A six-man Au-tonomous Underwater Vehicle(AUV) team is also part of thegroup from Singapore.

The RSS Valour, a Victo-ry-class missile corvette whichleft Singapore on the day of thecrash, returned to Tuas NavalBase yesterday, after assisting inthe Indonesian-led operation foreight days.

The vessel was received byChief of Navy Lai Chung Han andother senior officers.

In a press statement, Rear-Ad-miral Lai thanked the personnel in-volved in the search for “workingtirelessly, amidst challengingweather conditions”.

He said: “Our people have giv-en their all and their best duringthe multinational search opera-tion.”

A second ship, RSS Supreme,has also made its way back to Sin-gapore for replenishments afterspending more than a week at sea.

To date, the Republic has de-ployed more than 400 personnel,two C-130 aircraft, two Super Pu-ma helicopters, five navy shipsand a six-man AUV team.

awcw@sph.com.sg

By TEO CHENG WEEREGIONAL CORRESPONDENTIN PANGKALAN BUN

RESCUERS have recovered threebodies strapped to the same rowof seats on Indonesia AirAsiaFlight QZ8501 as the Indonesianauthorities expanded their searcharea to look for more victims andwreckage from the Dec 28 crash.

Search and rescue agency Ba-sarnas yesterday increased the sur-face search area by another 65 nau-tical miles east, to 295 nauticalmiles, to account for the directionof the waves.

Explaining the decision,Basarnas’ director of operations,Mr S. B. Supriyadi, told reportersthat strong currents could carrydebris and bodies in a south-eastdirection, towards the south ofBanjarmasin, the capital of southKalimantan.

On the three bodies strapped toa row of seats, he said: “The im-pact must have knocked thechairs off the plane’s floor.

“The bodies were found float-ing because of the sponge in thechairs.”

It is uncertain in which part ofthe plane they were seated, al-though Mr Supriyadi saidAirAsia’s analysis suggested thatthey could be from the front rowon the left side of the plane.

The three victims – who wererecovered by Malaysian vessel KDKasturi and flown later in the dayto Surabaya – brought the totalnumber of bodies found to 37 asthe search enters its 10th day to-day.

But the figure represents lessthan a quarter of the 162 passen-gers and crew on the ill-fatedflight as a multinational search in-volving ships and aircraft hasbeen hampered by almost day af-ter day of rough weather and chop-py seas.

There is still no sign of the cru-cial black box recorders, althoughofficials yesterday said an Indone-sian naval patrol vessel has foundwhat could be the tail of theplane.

That is the section where thevoice and flight data recorders,which are needed to determinethe cause of the crash, are locat-ed.

“We found what has a high

probability of being the tail of theplane,” said the captain of the pa-trol vessel Yayan Sofyan, after hisship returned to port in Surabayayesterday.

But Basarnas chief BambangSoelistyo cautioned against rais-ing hopes unnecessarily.

“I am not saying it’s the tailyet,” he told a news conferenceyesterday. “That is suspected.Now we are trying to confirm it.”

It has been a trying period forthe rescue teams, which are hop-ing for better weather in the daysahead.

Indonesian Air Force helicop-ter pilot Joko Subroto has been fly-ing out to sea from Pangkalan Bunabout twice a day, but the mon-soon season means that heavyrain has reduced visibility to lessthan 500m most of the time.

“I really hope we can completeour task soon, so that we canbring some relief to the familieswho are waiting,” he told TheStraits Times.

“The rain has made things diffi-cult but we keep trying. Only Godcontrols the weather.”

chengwee@sph.com.sg

The remotely operated vehicle on board the MV Swift Rescue was lowered into the water yesterday at a new location, where it stayed for about 45 minutes. Withvisibility less than a metre, operators were unable to locate any debris. ST PHOTO: SEAH KWANG PENG

Three bodiesfound strappedto row of seats

The recovery team from the USS Sampson hauling two airline seats out of theJava Sea on Sunday. There is still no sign of the crucial black box recorders, butthe tail of the plane may have been found. PHOTO: AGENCE FRANCE-PRESSE�

Strong currents hamper underwater search in new location

Search areaexpanded to lookfor more victimsand wreckage

AIRASIA FLIGHT QZ8501

Headwinds

Wind shear avoidance

Tailwind

Downdraft

Cloud base

Precipitation

Surface

HorizontalVortex

OutflowPrecipitation

Surface

HorizontalVortexVortex

Outflow

How a typical Pitot tube looks like

Wind shear avoidance

DowndraftDowndraftWind shear avoidance

ST GRAPHICS & REUTERS PHOTO: ISTOCKPHOTO

Gathering flight info: How the Pitot-static system worksThe Pitot probes and the static pressure ports are used to measure the altitude, airspeed and vertical speed of an aircraft. Ice can block these instruments, causing inconsistent speed readings that may cause a plane to crash.

Strong wind shear and ice could be a factor causing Flight QZ8501 to crash. Severe thunderstorms can produce lightning and microbursts, which are sudden, intense downdrafts of air.

WINDS OFDANGER

PITOT TUBES

PRIMARYFLIGHT DISPLAY

■ A plane entering a microburst encounters head winds that increase airspeed. The pilot normally counters this by reducing power.

■ As the aircraft flies through the headwind, it encounters a downdraft followed by a tail wind. This can cause a rapid reduction of airspeed and lift of the plane.

■ The pilots may be able to escape the microburst by adding power to the engines. But if the wind shear is strong enough, the plane could still crash.

MICROBURSTS■ Last from only a few seconds to a couple of minutes and measure less than 4km in size.

■ They can produce extremely strong wind shear, posing great danger to aircraft passing through it.

Sea

STAGES OF A MICROBURST

Curling winds accelerate and surface winds slow

down due to friction.

Cool air accelerates as it reaches the ground or water. Wind curls

outwards and spreads away from the point of impact.

Hail or large raindrops fall through drier air. As they

evaporate, the air becomes cooler and descends.

STATIC PRESSURE PORT■ Openings like this in the fuselage are used to get outside air pressure to flight instruments.

■ In the A320, they are fed toan air/data computer to calculate altitude, vertical speed and, in connection with the Pitot tube, airspeed.

Waterdrain hole

Pitot tube

Pitotpressurechamber

Anti-ice heaterPrevents icingfrom occurring

Anti-iceheater

Air

flow

The pressure of air entering the tubes lets sensors measure the speed and angle of flight.

The open end ofthe Pitot tube faces toward the flow of air

Around25cm long with a 1cm diameter.

■ A series of L-shaped metal tubes that jut from the wing or fuselage of a plane, where air rushes against it.■ A malfunctioning Pitot tube could cause an airspeed sensor to fail, leading the computer controlling the plane to accelerate or decelerate in a potentially dangerous fashion.■ A plane that flies too slowly can lose liftand crash, while one that is moving toofast can break up in the air.

Source: NASAPitot tube Static

pressureport

Information gathered from the Pitot tubes and the static ports show up on the flight instruments■ Artificial horizon■ Airspeed in knots■ Altimeter in feet above sea level■ Vertical speed in feet per minute■ Compass heading

NOTE:Diagrams

are notto scale

Cloud base

A6 TTOOPP OOFF TTHHEE NNEEWWSS T U E S D A Y , J A N U A R Y 6 , 2 0 1 5