HONDAY, JULY 29, 1974
INQUIRY INTO AIRCRAFT ACCIDENT COMPLETED
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THE CIVIL AVIATION DEPARTMENT INQUIRY INTO THE ACCIDENT INVOLVING THE AIR INDIA BOEING 707 VT-DNZ AT HONG KONG AIRPORT ON APRIL 1, 1974 HAS BEEN COMPLETED.
THE INQUIRY WAS CARRIED OUT BY MR. H.G.M. HOWELL OF THE CIVIL AVIATION DEPARTMENT ASSISTED BY CAPTAIN B.J. VICHTMAN OF CATHAY PACIFIC AIRWAYS LIMITED.
ASSISTANCE IN THE INQUIRY WAS ALSO PROVIDED BY THE OUREAU OF AVIATION SAFETY OF THE UNITED STATES DEPARTMENT OF TRANSPORTATION, THE LOCKHEED AIRCRAFT CORPORATION, THE HONG KONG AIRCRAFT ENGINEERING COMPANY LTD., THE U.K. DEPARTMENT OF TRADE, INDIAN AIRLINES AND THE AIRWORTHINESS ERANCH OF THE UNITED KINGDOM CIVIL AVIATION AUTHORITY.
THE GOVERNMENT OF INDIA WAS REPRESENTED BY MR. H.B. SINGH, DEPUTY DIRECTOR OF AIR SAFETY, AND THE INDIAN PILOTS GUILD BY CAPTAIN P.K. CHOSM.
THE AIR INDIA AIRCRAFT, AFTER MAKING THE APPROACH OVER KOWLOON, MADE A FIRM LANDING ON A VET RUNWAY WITH TAIL AND CROSS WINDS.
IN SPITE OF THE USE OF RUDDER, FULL BRAKING AND REVERSE THRUST THE AIRCRAFT WENT OUT OF CONTROL, SLID OFF THE RUNWAY AND CAME TO REST ON THE GRASS SHOULDER SOME 4,000 FEET FROM THE RUNWAY THRESHOLD.
THE RICHT MAIN LANDING GEAR OF THE AIRCRAFT COLLAPSED AND THE AIRCRAFT VAS EXTENSIVELY DAMAGED.
NONE OF THE CREW OR PASSENGERS IN THE AIRCRAFT WAS INJURED.
THE INQUIRY INDICATES THAT THE CAUSE OF THE ACCIDENT WAS LOSS OF CONTROL INDUCED BY AQUAPLANING IN THE CROSSWIND CONDITIONS.
AQUAPLANING IS CAUSED BY A VERY THIN LAYER OF WATER BUILDING UP BETWEEN THE RUNWAY SURFACE AND THE WHEELS OF THE AIRCRAFT WHICH PREVENTS BRAKING BEING EFFECTIVE.
ALTHOUGH PLANS HAD BEEN FINALISED FOR GROOVING THE RUNWAY SURFACE TO MINIMISE THE INCIDENCE OF AQUAPLANING, THE ACTUAL GROOVING OPERATION COULD NOT BE STARTED UNTIL SIX WEEKS AFTER THE ACCIDENT, AS IT WAS NECESSARY TO ALLOW TIME TO ELAPSE FOR THE NEWLY LAID SURFACE TO HARDEN DEFORE THE WORK COULD DE CARRIED OUT.
SOME 8,000 FEET OF THE RUNWAY HAS NOU RECEIVED GROOVING TREATMENT AND IT IS CONSIDERED THAT A RECURRENCE OF THIS TYPE OF ACCIDENT IS UNLIKELY.
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