Vectors For Safety - October 2021

NAFI MentorLive to Feature Gene Benson

The October 20 edition of NAFI MentorLive will feature Gene Benson as the presenter. Gene's presentation is titled, "Gate Keepers - Lessons from Experience and Research." The topic is primarily aimed at flight instructors, but all are invited to attend. The presentation will be at 8:00 PM Eastern on October 20. The link to view has not been released as of this writing, but it will be available soon at https://www.nafinet.org/mentorlive

Some Notes on Accident/Incident Trends

It is no surprise that most minor accidents and incidents happen during taxi. What is surprising is the seemingly significant increase in these events. Airplanes taxiing into parked airplanes is particularly disturbing. This could go from a minor property damage incident to a fatal accident if someone was in the process of doing a preflight inspection or boarding passengers when their airplane was struck by a spinning propeller. Let's vow to be more careful during taxi. We should be focused on the task of taxiing. We should not be tuning radios, programming avionics, answering text messages or anything else that can provide a distraction from the important task of safe taxi. We should also enforce sterile cockpit procedures during critical phases of flight, including taxi.

We are also seeing a disturbing number of runway excursions, both as running off the end and off the side. Most of these are happening during landing. We conducted a webinar on that subject a few months ago titled "Many Happy Returns." The associated free course for Wings credit can be found here and the YouTube video (no Wings credit available) can be found here. A bit of review never hurts.

Tick, Tick, Tick, Stop

There have been incidents of pilots executing a go-around following a prop strike during landing. That is a very, very, bad idea. If the propeller strikes the runway or any other hard object, and the airplane is on or just above the runway, it is almost always prudent to immediately close the throttle and concentrate on airplane control to minimize damage and chance of injury. If the prop strike occurs during a hard landing, the airplane is on or very near the ground, so it is best to stop. In most cases, even running off the end or side of the runway will result only in property damage. If the prop strike occurred because the landing gear had not been extended, that ticking sound should result in closing the throttle(s) and settling in for a gear-up landing. Why? The propeller will have been damaged, the extent of which cannot be determined yet. If a tip or more than a tip breaks off the prop during a go-around at high power, the vibration will be extreme, likely damaging the engine mount. There have been cases in which the engine has been torn from the airframe, making the airplane uncontrollable due to the center of gravity moving rapidly aft and out of the controllable range. It is better to live to fly another day.

Leaf Peeping in Your Future?

About a year ago, we conducted a webinar called "Autumn Scenery Safety." No Wings credit is available, but some good pointers can be found by watching the associated YouTube video.

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Fuel Selectors and Shotguns

What do fuel selectors and shotguns have in common? That seems like an odd question to ask in an article relating to aviation safety. I suppose that the answer is rather obvious to anyone familiar with both airplanes and firearms. For others, the answer is that both can cause injury or death if not used correctly or maintained properly.

The NTSB, in 2018, stated that in the previous ten years, 104 accidents had problems cited related to fuel selectors. Of those, 63 accidents involved the incorrect operation of the fuel, and 28 involved the fuel selector’s “degraded function.” Before we dismiss this as only about 10 accidents per year, we must remember that this does not include events categorized as incidents in which only minor airplane damage occurred. It also does not include power loss events in which a successful forced landing was accomplished and no report was filed.

Fuel selector maintenance is not foremost on the minds of most pilots. The selector is just something that is there and routine. Some are simple on/off devices, some allow for selecting one fuel tank or operating from both tanks. Still others are complex as they control the fuel flow from multiple tanks to multiple engines and allow for crossfeed from a tank to an engine on the opposite side of the airplane. Regardless of the complexity, a fuel selector is a critical component. An engine can be well engineered and impeccably maintained, but it will not run if it is denied fuel by the fuel selector.

In addressing mechanics, the NTSB states the problem as follows:

• Worn fuel selectors have led to fuel starvation and loss of engine power, resulting in serious and fatal injuries.
• Undetected wear of fuel selector components during required maintenance inspections could lead to fuel starvation.
• As fuel selectors wear, the fuel selector handles may be difficult or even impossible to turn. If a pilot applies too much force, the internal components can fracture and obstruct the fuel flow, resulting in a total loss of engine power.
• In addition, worn detents could make it difficult for a pilot to properly position the fuel selector to the desired tank. Positioning the fuel selector incorrectly to an empty tank or in between tanks could ultimately starve the engine of fuel.

The NTSB recommendation for mechanics is as follows:

• Inspect fuel selectors according to the airplane maintenance manual, checking the operation, condition, and security of the fuel selector.
• Ensure that stops or detents for the fuel selector valve position the valve properly.
• Service or replace any worn components, as necessary, according to the airplane maintenance manual and check your work to ensure accuracy.
• Be informed and review and comply with any applicable airworthiness directives and service bulletins regarding the fuel selector and components.

Of course, there is no guarantee that a properly maintained fuel selector will be properly operated by the pilot. Far too many accidents and incidents result from fuel mismanagement. That mainly includes a loss of engine power due to fuel starvation caused by a fuel selector incorrectly positioned by a pilot. The selector might be in the OFF position, might be positioned to a tank containing an insufficient quantity of fuel, or might be positioned between two detents such that fuel is not being taken from any of the fuel tanks.

In addressing pilots, the NTSB states the problem as follows:

• Worn fuel selectors have led to fuel starvation and loss of engine power, resulting in serious and fatal injuries.
• As fuel selectors wear, the fuel selector handles may be difficult or even impossible to turn. If a pilot applies too much force, the internal components can fracture and obstruct the fuel flow, resulting in a total loss of engine power.
• In addition, worn detents could make it difficult for a pilot to properly position the fuel selector to the desired tank. Positioning the fuel selector incorrectly to an empty tank or in between tanks could ultimately starve the engine of fuel.

The NTSB recommendation for pilots is as follows:

• Check the fuel selectors for proper operation during your preflight assessment, ensuring that the fuel selector moves freely and stays in the correct detent when selected and that fuel selector placards are accurate and legible.
• Do not force a handle that is difficult to turn; it could lead to fractured components inside the fuel selector that may prevent proper operation.
  • Do not fly if your fuel selector exhibits any of the following:
  • Sticking and binding,
  • Requires greater-than-average pressure to turn or move, or
  • Worn detents that do not stop the selector in the desired position.

• If you encounter any problems with the proper operation of the fuel selector, do not attempt the flight. Report the anomaly to maintenance personnel for inspection or repair.
• Be informed and review and comply with any applicable airworthiness directives and service bulletins regarding the fuel selector and components.

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 accident involved a Piper PA 32-300 and resulted in substantial aircraft damage, but fortunately only minor injuries to the two occupants. A loss of engine power occurred during a night flight so the pilot is to be commended for good decision making and for continuing to fly the airplane until it was stopped.

The NTSB accident report includes the following: "The pilot and pilot-rated passenger were conducting night touch-and-go landings and were in the traffic pattern for the second landing when the engine experienced a partial loss of power. The pilot advanced the throttle lever to increase the engine rpm, but the engine did not respond. The pilot moved the throttle lever, mixture control, and fuel selector and turned on the fuel pump in an attempt to troubleshoot the loss of power. Unable to restore engine power, the pilot made an emergency landing in a field. A postaccident examination revealed that the fuel selector valve was in the OFF position. The right tip fuel tank did not contain any fuel. The other three fuel tanks were mostly full of fuel."

Based on that statement, a logical conclusion would be that the pilot selected the wrong tank. But that conclusion is shown to be incorrect based on the following statement from the NTSB accident report. "Federal Aviation Administration Airworthiness Directive (AD) 77-12-01, applicable to the accident
airplane, was issued on June 10, 1977, to prevent a fuel system malfunction and a possible power
interruption. AD 77-12-01 requires regular inspection of the fuel selector valve; it was most recently
completed during the annual inspection, about 5 months before the accident, and no anomalies were
noted. A postaccident engine run revealed that the engine operated with no anomalies. The fuel selector
valve was obviously worn and degraded to the point that it would not control the fuel flow. The detents
were very worn and fuel continued to flow through the selector valve even when between detents and in
the OFF position. Thus, the loss of engine power was likely a result of the deteriorated fuel selector
valve, which allowed fuel to feed only from the right tip tank until it was exhausted. It is also likely that
the deterioration of the fuel selector valve was overlooked during the last annual inspection."

Photo Source: NTSB

The NTSB Probable Cause finding states, "Fuel starvation due to the deterioration of the fuel selector valve, which allowed fuel to be fed from only the right tip tank. Contributing to the accident was the inadequate annual inspection, which failed to detect the deteriorated valve."

Photo Source: NTSB

Two lessons can be learned here. First, thorough inspections that include rigorous compliance with any Airworthiness Directives and Service Bulletins are essential. We do not always know why a procedure is in place, but there is always a reason for it to be there. Many of the procedures that we might think are frivolous are import and many have been written in blood. The second to be learned is that this pilot, with only about 100 flight hours total experience and only 4 hours in this make and model, did an exemplary job of rapid decision making and of flying the airplane until it came to a stop.

Click here to download the full 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 accident involved a Mooney M20K and resulted in one death and one serious injury. The following excerpt from the NTSB accident report summarizes the event: "The commercial pilot and one passenger were departing on runway 36 when the airplane experienced a total loss of engine power about 200 ft above the runway. The pilot announced over the control tower frequency that the engine had lost power and that he intended to land the airplane on runway 26, which was located at the end of and perpendicular to the takeoff runway. According to the passenger and witnesses, the airplane completed a left turn to align with runway 26 before the wings rocked, and it rolled into a 90° left bank and collided with terrain. The passenger and witness observations were consistent with the pilot failing to maintain sufficient airspeed, which resulted in the airplane's wing exceeding its critical angle of attack and an aerodynamic stall."

Photo Source: NTSB

The accident report includes a lengthy description of the analysis that led to the following statement: "The fuel flow interruption and the loss of engine power shortly after takeoff were likely due to the pilot inadvertently placing the fuel selector in the "Off" position, which likely occurred when he completed the step in the Before Takeoff checklist that called for the fuel selector to be placed on the fullest tank. It is possible that the pilot inadvertently moved the fuel selector from the "Left Tank" position to the "Off" position instead of moving it from the "Right Tank" position to the "Left Tank" position. After the power loss, the pilot likely moved the fuel selector from "Off" to its intermediate as-found position in an attempt to restore engine power."

Photo Source: NTSB

The NTSB Probable Cause finding states, "The pilot's failure to maintain sufficient airspeed following a loss of engine power, which resulted in the airplane exceeding its critical angle of attack and an aerodynamic stall. Contributing to the accident was the pilot's inadvertent placement of the fuel selector in the "Off" position before takeoff, which resulted in fuel starvation and a total loss of engine power."

Photo Source: NTSB

There are two important lessons to be learned from this accident. First, assuming the NTSB is correct in that the pilot inadvertently selected the OFF position on the fuel selector just prior to takeoff then repositioned it to the LEFT position after losing power, never move a fuel selector just prior to takeoff. If the selector is incorrectly positioned, the engine will run as it consumes the fuel in the system downstream of the selector valve. This might be just enough fuel to get the airplane airborne. By moving the selector prior to the engine runup, any error in positioning of the selector handle will likely become evident before beginning the takeoff roll. If it is necessary to reposition the fuel selector handle after the engine runup, simply repeat the runup before beginning the takeoff. The second lesson relates what to do following an engine failure shortly after takeoff. If this happens for whatever reason, we must resolve to land straight ahead and steer to avoid any large objects. This pilot was not trying to return to the departure runway, but even the attempted turn to the perpendicular runway was too much. Let the airplane give its life to save yours.

Click here to download the full accident report from the NTSB website.

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