The Compliance Spectrum

The Compliance Spectrum

The Compliance Spectrum

It’s a phrase found frequently in NTSB reports: “The pilot’s failure to….” An (admittedly old) NTSB survey of accidents from 1978 through 1990 revealed that procedural noncompliance was a factor in 78 percent of all crashes. It’s one thing to say the pilot failed to comply with a procedure. It’s another thing entirely to understand why even good and well-meaning pilots are sometimes noncompliant and to develop strategies for making sure the pilot does things right. 

There are five uniquely different types of noncompliance, each with its mitigations – and unfortunately, accident histories. What might cause you to forget to do something or to do something wrong? How can you recognize where you currently fall on the compliance spectrum?  


Untrained (or Ignorant) Noncompliance From the NTSB:

The pilot advised ATC he was descending. However, the airplane climbed briefly, followed by a series of descents and climbs with varying airspeeds that continued for about five minutes. The pilot informed the controller he could not disengage the autopilot and requested radar vectors to return to the departure airport. While returning, the pilot said it took full forward and back control pressure to descend and climb, respectively, and he solicited and received assistance from another pilot on how to turn off the autopilot. The advice included pulling the autopilot circuit breaker, which the pilot said he did. The pilot apparently did not consult the emergency procedures for an autopilot pitch trim malfunction, which included a step to manually retrim the airplane. As the airplane turned to final witnesses saw it enter a vertical descent and impact a lake. Performance studies showed that, during the turn, the airplane was just two knots above its stall speed. It is likely the airplane experienced an aerodynamic stall. 

The NTSB probable cause:  

The pilot’s failure to maintain adequate airspeed which resulted in an aerodynamic stall. Contributing were the pilot’s misuse of the forward elevator flight control input with the autopilot engaged, which resulted in the full airplane-nose-up trim; his failure to recognize and correct the mis-trimmed airplane per the emergency procedures; and the excessive control forces required to maintain control in the mis-trimmed condition, which resulted in pilot fatigue.

One end of the compliance spectrum is what I call untrained or ignorant noncompliance. The pilot doesn’t do something or does something wrong because he/she does not know the checklist or procedure exists. 

The bulk of your training, and virtually all of your recurrent instruction, probably focused on stalls, steep turns, ILS approaches, takeoffs and landings, and similar skills. These are all vital, and history shows we need to train on them even more. But very little instruction and even transition training covers the design and operation of airplane systems – how the fuel system works, or dealing with electrical faults or the normal, abnormal and emergency operation of optional equipment like autopilots and electric trim. As we move into more complex airplanes, it takes more study and practice to master the systems. 

Most of what you need to know is in the Airplane Flight Manual (AFM) or Pilot’s Operating Handbook (POH). In the case of optional or upgrade equipment, the vital information is in the Supplement for that equipment. Supplements mirror the AFM/POH format. Take time now, and make time at least once each year, to read Sections II (Limitations), III (Emergency Procedures), IV (Normal Procedures) and VII (Systems Description) in both the AFM/POH and every Supplement for installed equipment. Use the checklists in normal flight; quiz yourself on normal, abnormal and emergency indications and procedures, and challenge your instructor to ensure you’ve mastered the systems on your next Flight Review or recurrent training event.

Stressed Noncompliance Another NTSB report:

The flight was operated by two airline transport pilots and it was the Beech 1900’s first flight after replacing an overhauled left propeller. Flight data recorder (FDR) data revealed that about two seconds after rotation, the left propeller rpm decreased to 60% and the left engine torque increased off scale (beyond 5,000 ft-lbs), consistent with the left propeller traveling to the feathered position and torque increasing in an attempt to maintain propeller rpm. About 30 seconds later the crew shut down the left engine and attempted to return to the departure airport. Post-accident examination revealed that the rudder trim was at its full-right limit, which would have occurred to counteract the left engine drag before its shutdown. The crew did not readjust trim when the drag was alleviated which resulted in the airplane being operated in a cross-controlled attitude for about 50 seconds, with a left bank and full-right rudder trim. Although the airplane should have been able to climb about 500 feet per minute on one engine, it slowed and descended from 300 feet in the cross-controlled attitude until it stalled and impacted terrain.

The NTSB probable cause: 

The left engine propeller’s uncommanded travel to the feathered position during takeoff for reasons that could not be determined due to impact damage. Contributing was the flight crew’s failure to establish a coordinated climb once the left engine was shut down and the left propeller was in the feathered position.

I’m going to give the two ATPs the benefit of the doubt and assume they had enough multiengine and simulator experience to know to trim the airplane after feathering a propeller and to establish zero-sideslip flight for single-engine climb. Further along the compliance spectrum, stressed noncompliance is a condition when the pilot(s) may know what to do and how to do it, but under the pressure of the moment, fail to follow the procedure. Stressed noncompliance is the result of two things: lack of recent training on normal, abnormal and emergency procedures, and denial that an actual problem exists.

In training pilots are pessimists – we expect and look for things to go wrong, and actively check and crosscheck the equipment and ourselves for anomalies and errors. Once the “dual received” logbook ink is dry, however, pilots are optimists – we expect things to go according to plan, and tend to think about the results of a flight (getting to destination, giving the passengers a smooth ride, etc.) and not about where we are, and what we are doing. The fix for stressed noncompliance is to train on normal, abnormal and emergency procedures regularly, review them frequently and fly the way you train – being as active a pessimist on routine flights as you are during training. 

Complacent Noncompliance From the NTSB:

A Gulfstream G-IV overran the runway during a rejected takeoff. The airplane rolled through the overrun area and across a grassy area, collided with approach lights and a localizer antenna, passed through the airport’s perimeter fence, and came to a stop in a ravine. The two pilots, a flight attendant, and four passengers died. The airplane was destroyed by impact and fire. The NTSB probable cause: the crew’s failure to perform the flight control check before takeoff, their attempt to take off with the gust lock system engaged, and their delayed execution of a rejected takeoff after they became aware that the controls were locked. Contributing were the crew’s habitual noncompliance with checklists, Gulfstream Aerospace Corporation’s failure to ensure that the G-IV gust lock/throttle lever interlock system would prevent an attempted takeoff with the gust lock engaged, and the FAA’s failure to detect this inadequacy during the G-IV’s certification.

This crash has become the “poster child” for complacent noncompliance, failure to follow procedures out of a feeling that nothing can go wrong and reinforced by “getting away with it.” The NTSB’s review of FDR data discovered that the specific flight crew had neglected to complete “controls free and correct” checks before takeoff “on 98 percent of the previous 175 takeoffs” in that airplane.

It’s easy to think that checklist steps and procedures aren’t important if you don’t think there are consequences for failing to perform them. The reality is that checklists tend to get longer, not shorter, as accidents occur. The answer to reversing complacent noncompliance is to use checklists and follow procedures religiously because they were written for a reason, even if that reason has not happened to you. Benefit from the disastrous experiences of others by never skipping checklist steps, even (or especially) when you’re in a hurry and more likely to miss something.

Intentional Noncompliance One more from the NTSB:

A Pilatus PC-12/45 was diverting when it crashed about 2100 feet west of the runway. The pilot and all 13 airplane passengers were fatally injured. Visual meteorological conditions prevailed. The NTSB probable cause: (1) the pilot’s failure to ensure a fuel system icing inhibitor was added before flight; (2) his failure to take appropriate remedial actions after a low fuel pressure state (resulting from icing within the fuel system) and a lateral fuel imbalance developed, including diverting to a suitable airport before the fuel imbalance became extreme; and (3) a loss of control while the pilot was maneuvering the left wing-heavy airplane near the approach end of the runway.

You might argue that this was a case of ignorant noncompliance if the pilot was not aware of the need for fuel system icing inhibitor. You could say it was a matter of complacent noncompliance, not adding the icing inhibitor or thinking maintaining fuel balance would not be critical to inflight controllability. I submit, however, that the pilot knowingly departed with an overloaded airplane that was also in a probable aft center of gravity condition that reduces control authority and stall protection at slow airspeeds – that he was intentionally noncompliant. The Pilatus, which had seats for 10 including the pilots, had 14
people on board (including several children) and was reportedly 600 pounds over maximum gross weight when it began the flight. The NTSB found the pilot flew “over 30 minutes” after exceeding the PC-12’s maximum fuel imbalance level before beginning to divert, overflying several suitable airports. The NTSB notes the ex-Air Force and airline pilot was rated at a “very high level” of proficiency in PC-12 training that occurred about two months before the crash.

There’s not much we can do to reduce the incidence of intentional noncompliance. I doubt it would do much good to list it here anyway as intentionally noncompliant pilots probably aren’t reading safety-related articles in Twin & Turbine. The FAA Hotline ( gives us a means of reporting violations of the Federal Air Regulations, but without hard evidence the FAA has nothing to go on. Tragically, most investigation of intentionally noncompliant pilots happens only after it’s too late.

Emergency Noncompliance

There’s one more category of non-compliance, one that happens successfully: emergency noncompliance. 14 CFR 91.3b tells us:

In an in-flight emergency requiring immediate action, the pilot in command may deviate from any rule of this part to the extent required to meet that emergency.

Emergency noncompliance is intentional, but it is the positive result of a pilot who is in command of the aircraft and the situation and does what it takes to get the airplane on the ground as safely as possible. You might call this “Catch 91.3b”: you can deviate from any rule in an emergency, but in an emergency, it’s not a deviation.

The Compliance Spectrum

Which type of noncompliance is “worst?” Obviously, knowing the rules but (outside of an emergency) violating them anyway (intentional noncompliance) is the most egregious. It appears these outliers are responsible for a significant number of accidents. But where can we make the greatest reduction in noncompliance events? I think the best chance comes from addressing ignorant and especially complacent noncompliance. It’s comparatively easy to learn how systems work, and how you work them, and to hold ourselves to a standard to use checklists and follow standard operating procedures. That, and practice to reduce the compliance effects of stress, seem like relatively easy strategies to make a big difference in what NTSB says is a factor in 78 percent of all accidents.

Where are you today on the compliance spectrum? Where will you be on the spectrum on your next flight? 

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