Find your blind spots! Keeping your left eye closed, hold both thumbs together and vertically at arm's length straight ahead, covering something like a clock or light switch on the wall.
Slowly move your right thumb to the right while maintaining your right eye focused on the object. Once you reach about 15 degrees of separation between arms, your right thumb will disappear (as long as you continue focusing on the object). Moving the thumb further to the right will cause the thumb to reappear.
One of the many fascinating things about our complex system of sight is that we have blind spots. Have you ever been driving and getting ready to switch lanes, thinking it’s clear, and then turning your head to double-check and realizing there’s a car driving next to you? That’s an example of a blind spot, the medical term for which is the scotoma.
Why don’t we see this daily? Our brains compensate by blending images from both eyes to create a continuous perception.
A blind spot also refers figuratively to gaps in our knowledge base, regardless of the subject matter. Much may not be important; for example, knowing that your aircraft wings use 2024 aluminum high-strength alloy is not critical. It is essential to know that they may be susceptible to fatigue cracks and must be monitored regularly.
While amassing a great deal of practical experience as we gain more and more flight time, we are all susceptible to having blind spots. That could be through omission or simply by forgetting something learned long ago. Remember working out performance data using arcane charts and graphs when taking your commercial pilot’s course? Revisiting them can be a humbling experience, as it doesn’t take long for rust to set in.
New environments, by definition, bring a new set of blind spots. Each time you fly to an unfamiliar airstrip, you must take it easy when adjusting to its layout, length, width, surface, etc. It’s what you don’t know – those pesky blind spots - that can quickly get you into big trouble. This is particularly important in ag aviation, where bare-bones airstrips with few or no markings, windsocks, etc., are common.
Here is one ‘blind spot’ example I witnessed. I was flying a Thrush S2R with another pilot (whom I shall call Dave) flying a Dromader off an unfamiliar grass strip oriented north/south with a noticeable downslope from south to north. We were both taking out the first loads, with Dave going first.
I intended to take off into the wind and uphill with my standard first-trip half load. Dave had elected to taxi for takeoff downhill and downwind. As I didn’t know his load size (I found out later it was a full load), I didn’t give it much thought.
I was parked in the loading area at the north end of the strip, watching Dave’s takeoff from the south. I wasn’t concerned until he was well down the runway with his tailwheel still on the ground. I recall thinking it would be close as he passed by with the mains barely airborne but with the tailwheel still on the ground. I can’t remember ever seeing that before in any aircraft.
As he disappeared into a cloud of dust, I saw what I initially perceived as a huge white explosion. What followed was nothing short of a miracle. Just beyond the north end of the strip was a shallow valley. Dave had skipped off the near side, staggering to get airborne, and then impacted uphill on the far side. The white explosion was his hopper gate blowing open with the impact.
There was no other damage other than the broken hopper door. We discussed it afterward, and he said he wasn’t sure which takeoff option was best but thought the Dromader had enough power to handle the situation. Such was not the case, and this is an example of how having a blind spot (e.g., the third option of a small load) almost caused a disaster.
Human Factors
“All I need is a few hours of sleep and some good, strong coffee. I’ll catch up on lost sleep in the off-season.”
I’ve heard this or similar comments from pilots of various experience levels. While most are generally aware of the effects of lack of sleep and the resultant fatigue, that knowledge can be overlooked when the demands of flying, regardless of our level of readiness, are considerable.
Blind spots come in all shapes and sizes. Early in my ag career, I discovered that no matter how fit you are, the combined effects of lack of sleep, stress, and fatigue can result in an accident waiting to happen. It happened to me while flying a Super Brave delivering a pre-emergent treatment over freshly seeded ground. Rain was en route, and the owner was dead set on getting the job done before its arrival, meaning we were putting in some pretty wicked hours.
As many can relate to getting ‘the nods’ while driving long distances, I got them at spray height. I can still recall the violent shudder as the wheels stuck the ground, luckily causing a big bounce and bringing me immediately to the here and now. I had just a few gallons left in the hopper, so I abruptly ended the session on the spot and headed back to home base to shut down, check the aircraft for any signs of damage, and get some good sack time. The blind spot here was in not fully appreciating how dog-tired I was.
While pilots are generally aware of the effects of stress and fatigue, they do not always fully appreciate how these factors influence decision-making and cognitive functions. This is particularly true in agricultural aviation, where a long line of anxious farmers at the airport gate chomp to get your aircraft over their crops.
How do we mitigate the effect of blind spots in our knowledge base? Here are a few proactive strategies to help bring blind spots to light.
- Regularly review your knowledge base to identify outdated or missing information.
- Encourage your staff to provide feedback and report any gaps or inaccuracies they encounter.
- To ensure diverse perspectives are covered, get insights from multiple sources, including subject matter experts and others in the industry.
- Stay updated with industry trends and new developments to integrate relevant information promptly.
Finally, always conservatively plan critical factors (load size, fuel load, required runway length, etc.). This will help minimize those pesky blind spots.
