Last week, I parked big yellow car (a 2002 Pontiac Aztek) with its sunroof just ever so slightly open, to ventilate the cooking temperatures inside. I thought the occasional bit of rain would not find its way inside the vehicle in any measurable amount. I was wrong.

In fact, quite some water found itself in the car after a few very brief showers. The water found some pathway from the roof down to the front footwells, where it collected. There was enough to moisten the multiple-layer carpets.

After moving away some plastic and prying the carpeting upward, I was shocked by the amount. In spots, an inch of water was standing in the sheet metal flooring, and its grooves. Some electrical wires were bathed, geez. It took an hour two to suck out most of the liter or so just sitting there. That amount makes me wonder whether there might have been a malevolent human element to the inflow. But I don’t think any of our neighbours would be that mean as to pour water in …. I think.

After beating myself up awhile for leaving that glass open even a little, I started wondering what the hell GM was thinking. There is no proper drainage path for getting rid of liquids from the cabin. There are nooks and crannies, but no reachable lowest point, no open drainage holes, nothing. On its own, water has nowhere to go but to slowly evaporate within. During a humid season, it won’t go anywhere. I even observed old-looking rust on some of the little fasteners that attach the plastic trim to the sheet metal. Some small amount of water must have been sitting there for months, undetectable.

In contrast, the airplane is full of little drainage mechanisms. Strategically placed holes at the lowest points of all the cavities, downward venting branches from other tubes, all intended to prevent water from accumulating anywhere inside. There are good safety reasons for this, since we often fly in below-freezing outside air, and water ice could block some necessary moving parts.