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IFR conditions on the flight deck
IFR conditions is the term applied to weather which restricts an aircraft to operating with reference to its instruments rather than navigating visually using references outside. A low cloud ceiling and/or restricted visibility due to fog or haze will always be a factor that triggers these conditions. In this story it was the cabin air compressor on Super VC10 G-ASGC (now on display at Duxford) which caused the crew to find themselves in IFR conditions.
"I was a flight engineer officer with BOAC/BA and operated the Standard and Super VC10s from 1964 until 1975. We had one particular trip, which went from Heathrow to New York (JFK), 48hrs slip (layover to the Americans!), JFK Bermuda JFK, 24 hrs slip, JFK, Prestwick (PWK), Manchester, 24 hrs slip, Manchester, PWK, JFK, 24 hrs slip, and finally JFK to LHR. I always regarded this trip as ‘Going to Manchester the hard way!’ The four technical crew in those happy days consisted of a Captain, First officer, another First Officer/Navigator and the Flight Engineer Officer. Both First Officers were fully qualified to sit in the right hand seat and to navigate. We had done the JFK and Bermuda bit of the trip –were on our way to Manchester via Prestwick from New York when the entire aircraft very rapidly filled up with dense smoke. We had departed JFK on G-ASGC for the overnight flight with the Manu-metric locks on the autopilot inoperative (‘B snagged’ to base). This meant that the Captain had to use the ‘Turn Knob’ on the Autopilot instead of using the ‘heading control knob’ (HDG) on the compass. We had just climbed through 18,000 feet (and changed the altimeters to 1013mb), were in a turn over Nantucket when I became aware of a strange smell rather like a hot electrical cable. I leaned out of my seat and opened the flight deck door to the galley and cabin and was amazed to see what appeared to be two walls of smoke coming together in the centre of the cabins. I called out the command “Crew on Oxygen”, and donned my mask and goggles. The VC10 crew masks were a very neat small device with a nylon helmet and ‘Pull Tag’ attached. To don the mask, all that the crewmember needed to do was to pull on the tag (that in turn extended the nylon helmet), which dragged the mask from behind its clear plastic hinged flap prior to sliding the helmet over one’s head. The oxygen mask plastic hatch was hinged at the bottom and when the mask had been pulled from the stowage, the plastic front cover fell down over the radio/coms panel switches.
I then pulled the ‘Red Knob’ and deployed the passenger oxygen masks, known as the ‘Rubber Jungle’! Covering the passenger’s mouths with an oxygen mask keeps the passengers alive and cuts down on the hysterical noises that they tend to make during moments of terror! In the few seconds that it had taken me to put on my mask and goggles the flight deck had filled with dense smoke. I could not see the engineer’s panel in front of me. Meanwhile the Captain had dis-engaged the Autopilot and extended the speed brakes. I was trying to carry out the drill and find the two starboard cabin air blower control switches and the R/H air spill valve in order to dump the fight deck air supply. This meant feeling the joints on the engineer’s panel, sliding my fingers around and identifying the switches by feel. It is surprising how many little bumps and lumps there are – some of them are very hot with the light bulbs underneath them. Meanwhile through the smoke a voice shouted, “We are through ten thousand feet at six thousand feet a minute”. – “A minute and forty seconds thought I” as the overspeed warning horn sounded. I felt quite a lot of ‘G’ and a few seconds later the slow speed stick shaker started to vibrate. This happened a few times. We couldn’t talk to each other because the plastic oxygen hatches were covering the Mask/Mike change over selector switches and all we could feel was the smooth surface of the plastic. By around this time I had managed to dump the air supply to the flight deck and the smoke started to clear a bit. The pilot/navigator (‘Ginger’) was face down on the throttle pedestal with his nose on the standby horizon, flying the aircraft with his left hand! The Captain couldn’t get close enough to see his instruments! I could just see the airspeed indicator on the engineer’s panel so I pumped the engines for 300 knots. The autopilot would not re-engage because the turn knob was still over. We had no idea whether we were on fire or what! As the smoke cleared a bit more I could see a red glow on my panel. Close inspection (and a bit of squinting!) showed that the fire warning lights fwd freight, rear freight, fwd outflow, rear outflow were all on. About this time the First Officer managed to change to mask mike and called a Mayday to JFK. “What’s the nature of your problem Speedbird 538?” he asked. “We are IFR (Instrument Flight Rules) in the flight deck” (said Phil) – “nicely put, thought I”! About this time I decided that if I could thin the air out (and thus the smoke) a bit more we might be able to see better. Every one was on oxygen so no one should get hurt. I cranked open the manual pressurisation valve and wound the cabin altitude up to several thousand feet. I can’t be sure that this did the trick but gradually we could start to see our instrument panels. We landed back at JFK some 10 tons over weight. We had been airborne 1 hour and 10 minutes. The station manager took us to the first class lounge and gave us a beer whilst we did the paperwork. One of the stewardesses told us that she had found an obviously male passenger clutching himself and an oxygen mask whilst standing up in the toilet! We all had a good laugh about that. Got his priorities right – oxygen first!
We found out afterwards that the number 4 cabin air compressor had pumped its oil into the air supply and that this had been the cause of our smoke. The hot electrical insulation smell had been the rotors in the number 4 cabin air compressor rubbing against the nylon housing. On the VC10 the R/H air compressors feed the passenger air vents and flight deck and the L/H compressors feed the pax cabin. We operated to Manchester the next evening. When we got to the Grand Hotel –
there was another crew waiting to take over our trip. Next morning the Captain
and I deadheaded to LHR where the ‘inquisition’ awaited us. The first question
that I was asked was “At what time did you press the event marker?” (On the
flight recorder tape). Anyway they couldn’t pin any thing on us so we all got a
commendation for not killing any passengers!" |
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