A fully loaded aircraft in the colours of a reputable airline departs on a routine night flight. It is being operated by a crew that has been trained to the latest regulations. During the initial phases of the flight, everything goes perfectly smoothly.
But what occurs next happens more often than it should: A minor system failure results in incorrect actions by the crew. There is apparently a lack of situation awareness and insufficient knowledge on aerodynamics and the aircraft systems. The crew is surprised by what their aircraft is doing, and do not hear what the airplane is trying to tell them. They may not be listening, or simply do not understand what the airplane is saying. They have not been adequately trained to react properly and immediately to those cues.
The airplane enters a stall. Instinctively, the pilots “PULL”; after all, a stall appears unimaginable in a modern jet. Still, the airplane tries1 to talk to its crew, screaming, with potentially violent stall buffet and audio warnings overloading their senses and masking other signals. Yet the aircraft continues to plummet to earth at extremely high angles of attack. There is no situation awareness, and the crew has no idea what to do as they helplessly see the altimeter tumble. There are no survivors.
How did we get here?
Upset Prevention and Recovery Training is considered a critical overhaul of current training programs, designed to reduce Loss of Control (LOC-I) accidents, which have claimed nearly half of all commercial airline fatalities in the last decade. Only recently have airlines started to embrace and implement comprehensive training concepts that can assist pilots in preventing these accidents.
Prior to the introduction of UPRT, training schools and airlines offered “Unusual Attitude” training, which essentially placed students into an extreme attitude and required them to “recover”. However, three major elements were missing: First, there was little or no attention dedicated to the prevention or recognition of upsets as these attitudes developed. Secondly, there had been little appreciation that the psychophysical or “startle” reaction by the pilots could influence their decision making. And finally, it later became clear that the largest contributing factor to LOC-I is stall. Therefore, adding upset prevention, startle scenarios, and recovery from stalls have now become global priorities.
What is UPRT?
UPRT attempts to integrate these three elements into a consolidated training process. Both regulation and an impetus to maintain high safety levels are driving airlines to rapidly deploy UPRT. However, some airlines have also had recent upset-related events and are embarking on safety enhancement programs involving UPRT: an All Nippon Airways Boeing 737 encountered an overbank upset during a routine flight due to an inadvertent rudder trim input by a pilot. A Chinese operator encountered a stall in an Airbus A319 in Normal Law during an approach in severe weather, bolstering the importance of adequate training to recognize and recover from stall events.
In 2009, the Royal Aeronautical Society created the International Committee for Aviation Training in Extended Envelopes (ICATEE) to identify and understand common threads in LOC-I incidents and accidents, and to recommend suitable training remedies. The recommendations made by ICATEE were integrated into the Manual of Aeroplane Upset Prevention and Recovery Training (ICAO Manual 10011) after being reviewed by the ICAO/FAA LOCART initiative. These include requirements for both initial and recurrent training of airline pilots, covering academic and practical training.
The ICATEE working group, founded and chaired by the author with nearly 75 industry experts on board, developed recommendations for both the training components and their implementation. A task analysis defined all 176 learning elements required for both upset prevention and upset recovery, covering four levels of mitigation:
A - Awareness (developing an understanding of the causal factors of upsets)
B - Recognition (early detection of conditions that could cause an upset)
C - Avoidance (immediate intervention to prevent further escalation of an upset)
D - Recovery (applying techniques to recover from a developed upset and re-stabilize the flight path).
In the above list of mitigation levels, stalls and upsets are synonymous. A), B) and C) are considered “prevention” mitigations, requiring both an adequate level of academic knowledge and the ability to recognize upset-related threats.
The objective is to develop the requisite knowledge and skills as early as possible in a pilot’s career, then to maintain them through recurrent training. Consideration must also be given to filling the training gap for the existing population of pilots through specialized training sessions, and possible limitations in instructor competencies as well.
ICAO Manual 10011 is referenced in ICAO Annex 1, Annex 6, and PANS-TRG, which applies to Multi-Crew Pilot License (MPL) training requirements. It is a global standard that is acceptable and amenable to all regions.
The FAA has issued Part 121.423, AC 120-109, AC 120-109A, and AC 120-111 to address UPRT, including post-stall training in simulators. These followed the Congressional mandate and Public Law 111-216 Sec 208, Implementation of NTSB Flight Crewmember Training Recommendations, signed by President Obama in 2010. FAA UPRT exceeds ICAO’s guidelines.
EASA issued in May 2015 additional acceptable means of compliance and guidance material for UPRT during operator conversion and recurrent training programs in ORO.FC.220 and ORO.FC.230, respectively, of the EU Air Operations Regulations. Operators in Europe must comply with this UPRT by May 2016 as required by the corresponding ED Decision 2015/012/R. For the licensing level and instructor qualification requirements, additional draft EASA materials are currently under review, including the use of aircraft to train pilots at CPL/MPL levels, and for instructor training. For the purpose of global harmonization, hopefully the final EASA regulations will be harmonized with the FAA rules for stall event recovery training.
Stall Facts and Stall Lore
Please read the following paragraphs with care and caution!
There exist several myths amongst pilots - including airline pilots and their instructors - regarding stalls; for example: “If I stall, I need first and foremost to apply thrust to power my way out”. Or “The proper technique is to level the wings first”. Or “Since the lifting surfaces are ineffective, I’ll need to use rudder”.
Furthermore, when asked “what defines a stall?”, many pilots state that it is a nose-down unarrestable pitch motion with uncommanded roll inputs. That reaction may be consistent with their stall experience in light airplanes; however, a commercial transport may stall differently. The vibrations felt in a commercial transport cockpit as the airplane nears its aerodyanmic lift limit may be surprisingly higher than a commercial pilot has ever experienced in their previous on-aeroplane stall training. Also, some commercial transports “mush” in a stall, which results in a high descent rate, but deceivingly with no perceptible no-down pitch break.
Before attempting to embark upon any form of a UPRT program, the academic knowledge is the backbone of that training. However, the wrong knowledge can lead to grave consequences: Consider a pilot applying skills learned from improperly trained instructors, who may also never have been exposed to upset prevention and recovery, or who may have been trained with inaccurate knowledge. Some of the comments previously made actually came from senior instructors, who had operated their reliable airplanes time and time again in the middle of the flight envelope, and in a system that perhaps allowed their skills to slowly erode. Some instructors, for example ex-fighter-pilots, may have “edge-of-the-envelope” skills, but may lack vital commercial airliner experience.
Knowledge can only be valuable when put into practice. We can learn that an immediate reaction to a stall warning by applying a slight nose-down pitch control application may qualify as “appropriate”. However, in the event that the airplane is inadvertently brought (by combined crew, weather or system failure factors) into a deeper stall, many things could happen: One wing often stalls before the other, rolling the aircraft. Instinctively, pilot reaction is to counter that roll motion with the opposite aileron input. Wrong! This could worsen the situation. The correct first action is to UNLOAD (forward control). Secondly, it may take considerable time, depending on altitude, aircraft type, loading, and depth into the stall to recover effectively. During the subsequent recovery, care must be taken after the stall to avoid oscillation, overspeed, high load factor or secondary stalls. It is no longer a routine Pavlovian reaction to the “first indication of stall”: It can become a hair-raising, adrenaline pumping challenge to re-establish stability.
Surprise Stall Research - Defining the Requirements
In a study published in 2014 by Dr. Jeff Schroeder, Chief Scientist for Flight Simulation Technologies of the FAA, he found in a simulator trial that less than one-quarter of 45 line pilots tested applied the correct stall recovery technique when surprised by an event. Considering that the FAA had published the correct stall recovery technique less than a year prior to the study, most pilots may have reverted to the technique that they had learned and been tested on repeatedly in their career - even when briefed on the correct technique just before the event. This shows how much re-training effort remains if these results can be generalized industry-wide.
Training full stalls will require enhancement to current FSTD flight models, so that the aerodynamics are represented accurately. When flight test data are not available, data from computation methods and wind tunnel testing may be used to satifactorily learn proper recovery techniques. Yet not everyone has adopted this approach: While the FAA has demonstrated both the benefits and defined safeguards to complete “full stall” training, EASA is awaiting additional data before finalizing its decision.
Whereas the term “stall event” encompasses either a “first indication of stall” or a “stall”, how the aircraft reacts can be markedly different- even though the desired reaction is the same: Reduce the angle of attack. Often, an aircraft is better behaved at the first-indication-of-stall, offering little temptation to do something other than reduce angle of attack. However, the degraded stability and control that arises at angles-of-attack beyond the first-indication-of-stall can expose learning deficiencies. That is, a pilot might try to level the wings if the airplane rolls significantly during a stall (e.g., Colgan 3407, Air France 447, and AirAsia 8501) or apply power before reducing angle of attack (e.g., Turkish Airlines 1951) as an urgent reaction to fix an ever-increasingly precarious flight condition. That is why training beyond first-indication-of-stall has benefits.
Of course, stall and upset prevention are the first and foremost objectives. We should never get there. However, it is doubtful that prevention alone will always work, and when the crew is placed on the “hot spot”, their instinctive reactions should still be to prioritize, apply their knowledge and handling skills, and collaboratively work towards successful resolution. Further, in several cases there has been no warning to the stall due to system failures or icing. Automated preventative protections are not foolproof, and upsets can occur without pre-stall warnings.
Competencies of Concern
LOC-I is the antithesis of maintaining control at all times. This is one of a pilot’s core responsibilities, exercised through the application of proper airmanship, discipline and teamwork. In terms of competencies, a recent survey was initiated under the EU Man4Gen project (see www.MAN4GEN.eu) during the 2015 EATS Conference’s Heads of Training meeting. The goal was to understand their concerns, priorities and where they will focus training in the near future. Fifteen senior training managers reacted to the survey. Seven of them considered UPRT (including stall recovery training) their highest priority. When it came to choosing the top three competencies, the results show that Situation Awareness, Manual Control and Workload Management appear to be of highest training priority. Please see Figure 1. This is congruent with recent safety data.
UPRT is ultimately about developing those skills and reinforcing those “competencies of concern”, through the development of manageable and proven strategies. Knowledge is the key, yet it must be practiced, and it should be checked to verify that a candidate demonstrates the correct recovery procedure.
Indeed, we need to maintain competencies that call for adherence to SOP’s, apply CRM and monitoring to instill teamwork to train both the soft and technical skills to proficiency. Clearly, airplanes should never be allowed to get into those upset or stall conditions, yet they do. UPRT saves lives because ultimately, in extreme situations, all of those causal factors lead to one recognizable and resolvable and trainable end state.
UPRT saves lives
When properly instructed, reducing the angle of attack is a bulletproof, low-cost, life saving and confidence-building technique. It is our responsibility to arm our pilots with the knowledge and skill for preventing and recovering from upsets and stalls. Hopefully, most pilots will recognize and prevent upsets. But when they don’t, when things turn sour and the adrenaline blocks reason, we need that final safety net. We need to listen to the airplane when it tries to talk to us, and know how to work with the airplane to resolve the situation.
Modern buildings have multiple levels of fire prevention and detection; however, this does not justify eliminating fire departments. Training for stall and upset recovery is the pilot’s fire department.
About the Author
Dr. Sunjoo Advani is an aerospace engineer and pilot. He is the CEO of International Development of Technology b.v., a company that develops simulation and training techniques for aviation, automotive and medical research. He was the founder and chairman of the ICATEE working group that developed global UPRT requirements. IDT currently supports regulators and major global airlines on best practices in UPRT implementation.