Breeze Tease
This month's feature blog discusses how wind, even light wind, can cause problems on takeoff and landing and how we can sometimes be fooled into thinking that the wind is manageable when it is not.
New Episode of "Old Pilot Tips"
Our new Episode 10 of "Old Pilot Tips" is now available. The topic of this under one-minute video focuses on the effect convection currents can have on our landing approach on a sunny summer day.. Check it out here.
Remove All Covers!
Even the most technically advanced GA airplanes still rely on the pilot to unleash their potential by removing all instrument, cowl, and vent covers during the preflight inspection. A Cirrus SF50 jet was substantially damaged during a botched landing in February that was attributed to the pilot's failure to remove the cover from the angle-of-attack vane. Download the accident report from the NTSB website here.
Again! Reverse Control Rigging after Maintenance
We have talked previously about the importance of checking the airplane carefully after it has undergone maintenance and we have stressed the importance of checking controls for full, free, and correct movement. In October 2022, a pilot was seriously injured in Kentucky when he did not discover that the elevator control had been rigged in reverse during maintenance until he applied forward stick to raise the tail during takeoff. Check out our short video on the subject here.
Breeze Tease
There is nothing like a nice gentle breeze on a warm summer day. But sometimes that seemingly gently breeze can be a tempting tease luring us toward trouble.
Flying an airplane is more complex than driving a car or other ground vehicle for mainly two reasons. The first is the added dimension of altitude and the other is the effect that even a small amount of wind can have. The difficulty of effectively managing the wind, especially on takeoff or landing, can seem to be squared or cubed if the wind is a gusty crosswind. Make that infinitively greater in the case of a tailwind.
Maybe it is not even officially gusty. Pilots tend to use the term “gusty” rather loosely. The National weather Service says gusts are reported when the peak wind speed reaches at least 16 knots and the variation in wind speed between the peaks and lulls is at least 9 knots. But problems can occur in small GA airplanes with lesser winds. This is evidenced by references to “gusty winds” in official accident reports when the wind does not meet the criteria for a gust. A 90° crosswind varying between 3 knots and 15 knots would not be officially gusty. But a pilot who might be a bit rusty on crosswind landings might reach task saturation landing on a narrow runway in that wind condition.
Most landing accidents and incidents have causal factors that include either an unstabilized approach or wind. Sometimes the wind is at least partially responsible for the unstabilized approach. The offending wind is often light, being not more than ten knots. It is no surprise that gusts are often mentioned in the pilot’s account of the accident or incident.
Perhaps the worst breeze tease of all is the tailwind. Mathematically, a tailwind of 6 or 7 knots should not have a great effect when landing a small GA airplane on a runway of reasonable length. But a search of the NTSB aviation accident database, going back ten years, produces 240 accidents (not counting incidents) in which the word “tailwind” appears in the probable cause. If we added the number of incidents, both reported and not reported, that resulted in airplane damage of some degree, we would see a substantially higher number. I believe that the problem in tailwind landings is mainly a sight perception problem. I know that there are some who disagree, but my opinion is that landing or taking off with a tailwind should be avoided.
To avoid being on the wrong side of a landing accident or incident, we must be more cognizant of the wind direction, velocity, and variability. We must constantly and realistically evaluate the anticipated task against our current level of proficiency. It is very important to obtain an accurate measurement of the wind at the destination airport just before entering the traffic pattern. If no accurate measurement can be obtained, then a couple of circles of the airport to closely observe the windsock, not just once, but over the period of a few minutes to check for variability is prudent.
In all our important decisions, including our aeronautical decisions, moving from the subjective to the objective is helpful. Good tools for that include using a Personal Minimums Checklist or Flight Risk Assessment Tool (FRAT). Equally important is that those tools are kept updated to accurately reflect our changing levels of proficiency.
Reprinted from NASA "Callback" Issue 511 August 2022
The Green Half-Mile
This C152 pilot experienced a common assortment of hazardous, hot weather factors that combined to produce an insidious, but predictable situation and potential disaster.
■ After landing at MRC for fuel, we elected to take off using the grass runway. The winds had been relatively calm, and despite training numerous soft field takeoffs and landings for private and commercial ratings, we had never actually used a grass runway. We spoke with some of the regulars in the FBO, who said that the turf condition was good, and they provided some tips for using that particular field. We had two pilots in the aircraft, which put the C152 within 3 pounds of maximum gross weight when full of fuel. We back-taxied the length of the field to reposition and test the smoothness of the turf. At the end, we turned a 180 and conducted a rolling takeoff without coming to a stop.
We suspect the combination of flying a 40-year-old airplane with pilots relatively new to the C152 also significantly reduced aircraft performance from the best-case numbers in the published charts. The biggest lesson learned is that when close to the margins on gross weight and high density altitude, always take the longest runway winds will allow.
Accidents discussed in this section are presented in the hope that pilots can learn from the misfortune of others and perhaps avoid an accident. It is easy to read an accident report and dismiss the cause as carelessness or as a dumb mistake. But let's remember that the accident pilot did not get up in the morning and say, "Gee, I think I'll go have an accident today." Nearly all pilots believe that they are safe. Honest introspection frequently reveals that on some occasion, we might have traveled down that same accident path.
Photo Source: NTSB
No one was injured but the RV7 was substantially damaged in this crash in November of 2022 in Englewood, Colorado. The NTSB report begins with the following: "The pilot reported that, during the initial climb following a takeoff from takeoff from runway 10, the airplane encountered a wind shift that forced the airplane back to the ground and it departed the side of the runway. During the runway excursion, the airplane sustained substantial damage to the right wing."
Centennial Airport Runway 10-28
The NTSB accident report continues, "Before the pilot’s departure another airplane reported windshear, a 15-20 knot gain on final for runway 35R. Low-level windshear advisories were in effect at the time of departure, and when cleared for takeoff, the controller reported the wind from 340° at 9 knots."
The NTSB Probable Cause states: "An encounter with windshear during the initial climb after takeoff, which resulted in a loss of control. Contributing to the accident was the pilot’s improper decision to takeoff with a tailwind."
Photo Source: NTSB
The pilot apparently did not file the Pilot-Operator Report with the NTSB, but the accident docket includes a report of a phone conversation between the NTSB Air Safety Investigator and the pilot. The conversation report reads, "KAPA Airfield Operations reported that the pilot had exited the left side of runway 10 near the C4 intersection. Airfield Ops photo documented the airplane and I gave permission for them to move the airplane so they could reopen the runway. A review of audio from LiveATC.Net showed that prior to the pilot’s departure another airplane reported windshear, a 15-20 knot gain on final on Runway 35R. KAPA tower controller reported that low-level windshear advisories were in effect. KAPA tower cleared the pilot for takeoff from runway 10 and called the wind from 340° at 9 knots."
My personal opinion after more than 50 years of flying and more than 15,000 accident/incident free flight hours is that tailwind takeoffs and landings should be avoided.
It seems likely here that the pilot's decisions were heavily influenced by the unconscious mind. Deciding to attempt a takeoff in a tailwheel equipped airplane with a quartering tailwind and reports of significant wind shear does not seem logical. Perhaps the pilot succumbed to our old nemesis, the "Bias Bundle Bomb." Illusory superiority might have convinced him that his skill was superior to that of other pilots. Optimism bias may have led him to believe that everything would be fine. Perhaps he thought it would be okay "Just This Once." And maybe continuation bias caused him to focus on completing the task and filtered out the information about the wind shear.
This mishap most likely could have been avoided by the use of a realistic decision making tool such as a Personal Minimums Checklist or a Flight Risk Assessment Tool (FRAT).
Click here to download the accident report from the NTSB website.
Accidents discussed in this section are presented in the hope that pilots can learn from the misfortune of others and perhaps avoid an accident. It is easy to read an accident report and dismiss the cause as carelessness or as a dumb mistake. But let's remember that the accident pilot did not get up in the morning and say, "Gee, I think I'll go have an accident today." Nearly all pilots believe that they are safe. Honest introspection frequently reveals that on some occasion, we might have traveled down that same accident path.
Photo Source: NTSB
This crash happened in Colorado in October 2022. The 38-year-old, 1400 hour commercial pilot was seriously injured and the airplane, a Pober Pixie, was substantially damaged. The NTSB accident report states: "The pilot reported that he had just purchased the airplane. During the second takeoff the airplane encountered a “violent variable wind gust”; the left wing rose unexpectedly, and the airplane stalled. The pilot reported that there was not enough altitude to recover and the airplane impacted the ground, which resulted in substantial damage to the right wing and fuselage. The pilot reported that there were no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation. At the time of takeoff, wind was reported as 250° at 23 knots, gusting to 30 knots." We should note that the takeoff was attempted on Runway 33 which calculates to be an 80 degree crosswind.
Graphic: GoogleEarth annotated by GB
The NTSB Probable Cause states:: "The pilot’s failure to maintain control during the takeoff with strong gusty surface wind."
In the NTSB Pilot-Operator Report, Safety Recommendation section, the pilot stated, "In this situation, I do not think there was a way it could have been prevented."
Phot source: NTSB
The pilot is likely correct in that once the takeoff had begun, the outcome was probably not preventable. Prevention would have been best served by better decision making before the takeoff attempt. The decision should have included consideration for the lack of experience in the accident airplane and the reported wind. We could again talk about the Bias Bundle Bomb of cognitive biases and the use of decision tools such as a Personal Minimums Checklist or Flight Risk Assessment Tool (FRAT).
Click here to download the accident report from the NTSB website.
Accidents discussed in this section are presented in the hope that pilots can learn from the misfortune of others and perhaps avoid an accident. It is easy to read an accident report and dismiss the cause as carelessness or as a dumb mistake. But let's remember that the accident pilot did not get up in the morning and say, "Gee, I think I'll go have an accident today." Nearly all pilots believe that they are safe. Honest introspection frequently reveals that on some occasion, we might have traveled down that same accident path.
This crash in Virginia in March 2021 took the life of the 77-year-old, 4,000 hour pilot. The Beech C23 was substantially damaged. The NTSB accident report begins, "The pilot was attempting to depart from a 1,900-ft-long turf runway, and customarily would depart toward the south as the runway sloped downhill in that direction (a total elevation change of about 50 feet). A witness described that, during the takeoff, the airplane was departing with a tailwind. The wind conditions at the closest weather reporting station about 13 nautical miles away indicated that a right quartering tailwind likely prevailed, with a right crosswind component of 21 knots and a tailwind component of 12 knots, gusting to 14 knots. The airplane subsequently impacted the tops of trees about 300 feet beyond and to the left of the runway departure end, and continued about 300 feet farther before coming to rest. Postaccident examination of the wreckage revealed no evidence of any preaccident mechanical malfunctions or failures with the airplane or engine that would have precluded normal operation."
Photo Source: NTSB
The NTSB report continues, "The takeoff performance chart for the airplane indicated that a ground roll of 1,236 ft was required on a grass surface, and 2,068 ft was needed to clear a 50-ft obstacle. The chart did not contain a correction factor for a takeoff with a tailwind, which would require a longer ground roll and takeoff distance. With the available runway distance of 1,900 ft, the pilot would have been operating the airplane near the limits of its performance capability before accounting for the additional distance required due to the prevailing tailwind. Given this information, it is likely that the pilot’s decision to depart in the gusting tailwind conditions resulted in an inflight collision with trees during the initial climb."
Photo Source: NTSB
The History of flight section in the NTSB report contains the following: "The pilot was departing from runway 19 at Krens Farm Airport (14VA), Hillsboro, Virginia. A witness reported hearing the airplane take off and looked back to watch it depart. When she saw the airplane, it was “tilted to the left” as it descended into the trees. She heard the engine the entire time and stated that it made “traditional engine noises.” In addition, she noted that relative to the airplane’s takeoff direction, a tailwind prevailed at the time of the accident. The pilot’s son reported that his father always took off from runway 19 because of the slope of the runway."
Graphic source: NTSB
The NTSB Probable Cause states, "The pilot's improper decision to depart from the short turf runway with a tailwind."
Photo Source: NTSB View looking down the takeoff runway
The crash occurred at the pilot's home airport so he was familiar with the issues of a sloping runway and wind patterns. According to the performance calculations performed by the NTSB, the takeoff was doomed before it began. We cannot know why the pilot made the decision to depart under the existing conditions. Perhaps he underestimated the wind speed. Maybe external factors played a role since the purpose of the flight was to visit an avionics shop for ADS-B installation. Maybe he had become complacent about the risk involved in the use of the short runway. We will never know why he decided to depart on that day in the existing conditions but we can learn some lessons. We should always do our preflight planning which includes calculating the takeoff distance given the existing conditions. Any tailwind should raise a red flag requiring additional scrutiny. Never let an external factor influence our aeronautical decision making.
Click here to download the accident report from the NTSB website.
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