Cumulonimbus ahead!

(Some of the following was recorded with my husband's assistance.)

Flying back from Iroquois after a very hearty brunch at the Monte Cristo restaurant and a walk right round the airfield past the boathouses to the beach where four of us cooled our feet in the river water—turned out to be "a useful learning experience".

Though it was lovely weather down by the St. Lawrence, we could see towering cloud formations building up to the north—in fact I (ever the pessimist on these expeditions) was the first of our party of eight to notice them—and when Chris started up PTN we already had confirmation of thunderstorm activity on our Strikefinder, "lighting up like a Christmas tree," as he puts it.

"We'd better be on our way, then," said our four pilots, "and see if we can get home in time". Chris, Don and Laurie asked for transponder codes, but Roger, preferring to keep out of the Ottawa airspace on his return flight, decided not to do so.

On the roll, Chris had his first learning experience of the flight when he noticed that PTN's Airspeed Indicator wasn't working. (There must be some blockage in our pitot tube—see picture—we don't yet know what has caused it.) He instinctively decided to continue his take-off as the runway at Iroquois is neither long enough (2000 feet) nor wide enough (23 feet) for second thoughts, and coming back in for a landing there without a functional ASI wouldn't have been a safe option either. So we carried on climbing and headed north towards Rockcliffe, Chris guessing at our airspeed by the "feel" of the plane and the indications of the other instruments (pilots practise such scenarios during their training so the situation wasn't altogether new for him and I didn't feel over-anxious as his passenger).

It soon became clear that the big black clouds were directly in our way, so Roger veered off towards the east to give them a wide berth and we had also begun a turn to the east, telling ATC we'd be going "around the weather", when we heard Don, well ahead, broadcasting his intention to make a beeline for Ottawa International Airport in order to sit out the storm that now seemed to be developing in the vicinity of Rockcliffe.

"That's a wise decision, if I may say so!" commented the Air Traffic Controller, at which Laurie's voice was heard to announce that he would do likewise, and Chris immediately chimed in, saying that he had changed his mind and was going to come in behind the other two, requesting a straight-in approach to Runway 32 at Ottawa. Unlike Roger, we had abandoned the idea of landing at Pendleton to wait out the storm at the gliding field. All the same, I didn't like the thought of deliberately flying towards the blackness ahead and asked Chris how long it would take us to get down to ground level at Ottawa. Ten minutes, he said, and we'd speed up during the descent. We picked up the localiser and glideslope and flew the ILS to runway 32. We had no idea how quickly we'd be coming down because our Airspeed Indicator was still out of order. In fact we landed with a bump as Chris slightly misjudged the last few feet of descent.

Don and ATC were correct and the storm by-passed us to the north of the big airport, over the city, remaining directly over our home airport for about a quarter of an hour, while we sat impatiently but safely on a corner of Ottawa's taxiway "Juliette", the three pilots and their passengers gesticulating at one another through the cockpit windows and communicating by means of cellphones. Chris also had the presence of mind to communicate with the Ottawa Tower controller through his spare, emergency, hand-held radio. By this means the controller, with reference to the precipitation indicated on his radar screen, was able to give us an idea of how close the next storm was, there being a series of them in the offing. On our behalf the tower controller asked an aircraft arriving from the north whether it would be possible to get into Rockcliffe. The answer was "only for the next three minutes".

We waited for another 10 minutes and then the controller told us that the next storm was already passing over Carp, which meant we had a short (!) window of opportunity in which to make the short hop to Rockcliffe between the end of one storm and the beginning of the next.

Unusually for Chris, we took off without going through the full pre-flight checklist (which takes about 5 minutes, as a rule). He wanted to make a quick getaway to allow the other two pilots enough time, in our sequence of take-offs, for a safe escape. Despite the fact that Chris had tried to unblock the pitot tube by stabbing it through its hole with a pen during our enforced wait on the ground, the ASI was still hovering around 50 mph at take-off, when it should have been reading about 60 mph, which meant we would have to accomplish another landing without its help, perhaps in the gusty conditions that often precede a storm. Fortunately though, the windsock at Rockcliffe gave no cause for alarm as we came overhead, and Chris, now able to anticipate the adjustments necessary for a descent without reference to our airspeed, brought us down to a remarkably smooth landing. Laurie and Don came down uneventfully behind us, clearing the runway with their usual sense of satisfaction.

So six of us were safely home but the storm from Carp was now almost upon us. Were Roger and Francine still airborne? We had no idea. Roger's fellow pilots began to "pace up and down", as Yiwen put it, observing their concern with great interest (she is a recently licensed pilot who had come along as a passenger on this occasion); they made a few 'phone calls, ascertaining that Roger's Cessna was safely on the ground at Pendleton. Another longish wait; nobody felt inclined to drive home until Roger and Francine could rejoin us. At last we heard they were in the air again, deviating south to avoid the cumulonimbus, but making for Rockcliffe. Another storm had just come through, the heavy rain bouncing off the ground and obscuring the buildings on the near horizon, all the club aircraft and owners' aircraft tied down and Tony sheltering in his barbeque hut. This one would probably be classified as a "light" thunderstorm, despite the many flashes of lightning and thunder-cracks that accompanied it, because there was no hail, and it wasn't preceded by excessive gusts of wind (a "heavy" thunderstorm can generate winds of over 100kph or even tornadoes). In fact the winds we were watching from the shelter of the Rockcliffe clubhouse behaved with text-book predictability, blowing from the centre of low pressure, first from the west as the storm approached, then gusting from the south as the darkest part of the cloud passed by a mile or so to the south of where we stood; then as the storm receded the windsock began to swing from the southeast. Shortly thereafter we heard Roger's voice on the clubhouse radio, broadcasting his position south of the field and coming in for an approach to runway 09, from the east, and then he too landed safely.