Prevention of Loss of Control in-Flight (LOC-I)

Loss of Control in-Flight (LOC-I)

If you happen to be a pilot: Did you ever experience an engine failure in-flight? Probably not - thanks to the extraordinary reliability of modern engines. Nevertheless, nobody would question that the skill to master an engine failure is regularly trained during recurrent training in order to keep you proficient in case you are confronted with it.

Why not do the same with the prevention and avoidance of "Loss of Control in-Flight" (LOC-I), still the No. 1 killer in civil aviation - even in commercial jet operation? LOC-I cases are quite complex but they do not occur like an unavoidable natural desaster. They do start with a trigger event and follow certain steps - which are all recoverable - until the disastrous non-recoverable loss of control situation could emerge as the crew could not react properly due to lack of necessary skill. 

For the prevention of LOC-I upset and stall recovery procedures and training is important as upsets or even stalls can be taken as the last chance for a recovery - but it is of similar importance to be able to recognize trigger events with LOC-I potential! Trigger events can be recognized and identified if the crews are familiar with certain interdependencies and if they are trained in keeping situation awareness despite non-annunciated malfunction of the autoflight system or despite non-annunciated unreliable primary flight indicators. In case of upsets or stalls FAA and EASA recommend to disconnect the autoflight and autothrottle system and take over manually. How can you take over a possibly severely misstrimmed a/c with uncertain energy status if you - as PF - and your colleague acting as PM are not fully aware of the situation? 

The theoretical course "give LOC-I no chance" and the complementary practical course "bLOC©" (beat LOC-I) are the professional answers on the training demands for a productive prevention and avoidance of LOC-I. The theoretical course which is offered as conventional class room training at customers sight or as distance teaching via internet has been basically designed as a stand alone training but may be complemented and enhanced by the practical training "bLOC©". (In this case the theoretical course is shortened to avoid overlapping).  

The practical “bLOC©” (beat Loss Of Control) course is conducted on the full motion flight simulator and advanced spatial disorientation trainer AIRFOX® ASD with unlimited yaw. The simulator has been developed and manufactured by AMST-Systemtechnik GmbH (, and stands for best possible transfer of training. Alternatively, the modified all attitude, motion perception and upset and stall recovery practical training can be commenced on aerobatic aircraft.

The design of both trainings respects requirements resulting from accident analysis and follows latest recommendations of FAA and EASA for upset and stall recovery procedures, scenarios and techniques. Since avoidable LOC-I cases are not a homogeneous group of accidents caused by a single factor it is worth to analyze the individual links of the “Bad Chains” finally causing LOC-I cases as schematically shown in Fig. 1.


Fig. 1: Bad Chains causing Loss of Control in Flight (schematic)                             Source: Rolf Huhne

There is evidence that most avoidable LOC-I cases are preceded by upsets or stalls and most upsets or stalls are preceded by loss of situational awareness (LSA). There is suspicion that LSA could have been avoided if the crews had undergone an efficient training before. LSA and upsets/stalls are triggered by various reasons which can be allocated to either technical malfunctions, human factors, or severe atmospheric disturbances.

An efficient training for the prevention and avoidance of LOC-I must be composed of a theoretical training addressing the individual triggers as shown in Fig. 1 and other main subjects such as motion perception, functions of the individual mental motion model, reasons for spatial disorientation and how to keep LSA, aerodynamics of flying at high angle of attack (AoA) up to stall and post-stall as well as best suitable upset and stall recovery techniques, and the use of secondary indicators in case of unreliable primary flight instruments. An efficient practical training aims at improvement of the pilot’s skill in the field of human factors including spatial disorientation, motion perception, and upset and stall recovery techniques from “all attitudes”. Since stall and post-stall recoveries and spatial disorientation cannot be trained in a real jet transport special motion simulators are needed with an enhanced generic airliner model representing the realistic aerodynamic behavior of the a/c at high AoA up to stall and post-stall. Sustained g-forces during upset and stall recoveries are desirable as most airline pilots are not familiar with g-forces up to +2,5g during recoveries from nose down attitudes. Alternatively, the practical training can be conducted on aerobatic aircraft.

A more detailed RATIONALE of an effective training for the prevention and avoidance of LOC-I can be downloaded here: LOC-I_training-rationale_3.1.pdf Download

The suitability of different training tools (1. aerobatic aircraft, 2. FTD/FNPT, 3. FFS, 4. AIRFOX ASD®, 5. DESDEMONA®) for each of the required training elements is shown in Fig. 2 below.

 Fig. 2: Suitability of Training Tools                                                                      Source: Rolf Huhne

Charts for better resolution download "LOC-I_triggers_suitability-training-tools.pdf"

The only simulator fulfilling all the requirements without limitations is DESDEMONA®, an extremely versatile motion platform equipped with a fully gimbaled (all attitude) cabin in a sledge which can be centrifugated up to ±3,0g. Also, a generic jet transport model enhanced for flights at high AoA up to stall and deep-stall conditions is implemented. DESDEMONA® has been commonly developed by AMST-Systemtechnik GmbH ( and the Dutch research institute TNO ( The simulator is located at the premises of TNO and is run by DESDEMONA Ltd. (

The full motion hexapod based AIRFOX® ASD flight simulator and advanced spatial disorientation trainer with additional unlimited yaw - developed and manufactured by AMST-Systemtechnik - fulfills likewise all requirements except sustained g-loads. The simulator opens the unparalleled possibility to combine full motion (6 DoF) with unlimited yaw which is a prerequisite for training of certain spatial disorientation phenomena, and for the demonstration of the important somato- and oculogyral effects including the vestibulo-ocular reflex (VOR). The simulator provides a realistic motion perception during spin and spin recoveries in VMC and IMC. The trainee can experience that during spin recoveries the strong perception of turning in the opposite direction lasts much longer in IMC than in VMC under visual ground contact. In VMC the strong “false” motion perception is suppressed within tenths of a second as a function of the individual mental motion model. In IMC (no visual ground contact) the mental model cannot interfere due to lack of visual references. It is like a “mental model disconnect”.

The “feel true” motion provided by the AIRFOX® ASD simulator and the enhanced special generic aircraft model dedicated for flying at high AoA speak for the best possible transfer of training for airline pilots as well as for commercial and private pilots with or without instruments rating (tailored training programs). All training elements are either maneuver oriented with the possibility to repeat these elements immediately for training purposes if required or embedded in a realistic sequence of line oriented training environment.

Alternatively, most of the practical training elements can be trained on small aerobatic aircraft.