N892PA. Pan American Boeing 707-321B c/n 20029-790.
Take-off accident at Sydney Airport - December 1, 1969.
In the late 1960s, Sydney’s main runway was as it is now, Runway 16 with the reciprocal being Runway 34. What was different then was that the runway pretty much terminated at the natural shore of Botany Bay and hadn’t yet been extended into the Bay. It is now 13,000 feet long but back then its length was only 8,000 feet.
Fringing the northern end of the runway, was a pretty significant drainage canal which cleared stormwater from Tempe, Sydenham Marrickville etc into Botany Bay. Further north again was the Tempe Tip, a 'Club Med' for seagulls, which were a persistent problem at Kingsford Smith Airport.
If my memory serves me correctly QF530, a B707-338B departed every evening around 1900 for NAN/HNL/SFO/JFK/LHR. Pan American's Flight PA812, also a Boeing 707-300 series, departed a bit earlier, at 1745.
In the old Terminal (of Sacred Memory) Pan Am’s checkin counter adjoined ours, with a common wall separating them. In fact there was a removable panel in the wall so each airline could use the other’s baggage belt if theirs failed.
Pan Am’s staff in those gentle days, included Kevin Simpson, Norm Brown, the McCoy twins and the delectable Carmen Lucia Almeida (who unwittingly supplied my nom de lerve, Juan) , plus others whose names elude me.
It was the evening of Monday 1st December 1969, the surface temperature was 26 degrees Celcius, the wind north easterly at 15 -20 kts but gusting to 25 kts. Pan American Flight PA812 had departed the terminal about 1750 to the south, for a takeoff northwards on Runway 34.
Sydney Airport (current view) Runway 34 runs diagonally from the 2pm to 8pm position
The time was about 1758 and I was walking back towards the old International Terminal Building (ITB) from the direction of Hangar 96. I guess loading had just started on QF530.
The first thing that caught my attention was the prolonged application of reverse thrust coming from the duty runway, long before any airplane came into view. I was watching the runway when suddenly PA812 appeared, nose dipping heavily under brakes and reverse thrust.
According to the DCA report, at this stage the airplane was departing the runway centreline to the right, although that wasn’t evident to me. Maybe the crew had realised an overshoot was inevitable and were trying to steer away from all the runway infrastructure that was heading their way at about 70 kts.
I remember starting to run as the plane left the sealed surface and started throwing up dust and approach light stalks before coming to rest, luckily about 50m short of the Tempe Canal. At this point my memory has unravelled.
I can just recall muddied, distraught passengers being bussed in to the Terminal for processing - the Pan Am ground staff may have even used one of our tarmac bases but I can’t remember for sure. The evacuation was copybook, and there were no injuries amongst the 11 crew and 125 passengers. All exits including the 'overwings' were used.
As it turns out about 5,000 feet into its takeoff roll the plane had flown through a flock of seagulls, ingesting a couple into No. 2 engine, which started to lose thrust. The Accident report reveals the crew believed the birdstrike and the decision to abandon the takeoff occurred before V1, while the FDR (Flight Data Recorder) indicates it occurred after V1.
(There are several reference speeds associated with the Take-off, all using V to indicate speed – V1 is the pre-calculated speed, below which the aircraft can stop safely if there’s a problem. Beyond V1 the takeoff should continue.
VR is the speed at which the pilot 'rotates' the plane by pulling back on the control column resulting in the surrounding trees starting to get smaller.
V2 is 'Takeoff Safety Speed' or the speed at which the airplane can be considered happily airborne. The landing gear can be retracted and maybe flaps too.)
Notwithstanding this, the report concludes that it should still have been possible for the aircraft to have been stopped before leaving the runway, had the post accident investigation not disclosed a significant error in the fuel delivery figures which resulted in the plane being 6,800 lbs over the RTOW.
(RTOW is 'Regulated Take Off Weight' - the maximum take off weight that’s been reduced from the manufacturer’s recommendation because of local influences, such as high temperatures, runway length, aircraft defects etc)
In the report there’s a suggestion that the baggage weights used might not have been accurate, but the evidence of error points unambiguously at a faulty hydrometer used by the engineers to determine the fuel's Specific Gravity (SG).
The actual SG was significantly higher than that read from the hydrometer and instead of the aircraft taxying with 131,000 lbs (including the 1,000 lbs allocated as taxi fuel) there was 137,721 lbs on board when the aircraft powered off its parking bay.
I remember too that the aircraft sat with its nose in the mud for a day or two until it was removed and towed to the Qantas hangars. Before this happened engineers had to remove the vertical stabiliser with the Pan American logo on it as it posed a 'safety hazard to normal airport operations'. Whether this was to spare Pan Am’s blushes or for obstacle clearance issues on the approach to Runway 16, I don’t know.
My only other memories of the incident are of the airplane being in Hangar 131 for a long time, while the damage was fixed and the aircraft repatriated.
John McHarg, Denmark, July 2011
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