(L/D)max Aviation Group

In addition to instruction in aircraft accident investigation, (L/D)max Aviation Safety Group will be conducting research focused on investigation techniques and analysis to improve the quality of investigations. Areas of research may be as brief as looking at evidence a new way, improving analysis by offering alternative interpretations and recommendations, or developing investigation methodology or training in new innovative ways.

At (L/D)max Aviation we understand that valuable input comes from a variety of sources. Knowing that there is much to gain from experts in a number of areas of aviation, we welcome comments about our on-going research topics and are open to suggestions for additional research areas. Although (L/D)max Aviation is a for-profit company, and therefor we are currently not eligible for US Federal Grants, we invite participation by those looking to further our goal of improving aviation accident investigation's contribution to the overall safety effort.

In most cases, the results of the research will be in the form of either a submission of "white papers" or presentations at professional seminars. The topics currently being researched by one or more of our associates is outlined below. Following each topic is a list of requested assistance to further the on-going research. (L/D)max Aviation is looking for valuable comments and/or suggestions to fulfill those areas from any person or organization in the aviation industry or that can contribute to this field and that is willing to help. Significant non-editorial suggestions to enhance the research topic are similarly welcome. If you have suggestions for additional investigation research our team always welcomes those ideas. In addition, (L/D)max Aviation's team of experts looks forward to the opportunity to assist other researchers as well as we all move towards the goal of improving aviation safety around the world.

Please forward any comments, suggestions, topics or offers of assistance to Gary Morphew at: gary.morphew@ldmaxaviation.com.

Air transport aircraft are increasingly involved in overrun landings. The damage and injuries as a result of these events indicates that awareness, risk assessments and procedures are frequently not sufficient to predict the conditions. In all cases, the aircraft were landed by professional crews and, for a variety of reasons, they failed to stop on the remaining runway. Also, a go-around would probably have been the best solution as the conditions were such that a safe landing became doubtful before touchdown. These events involved all types of aircraft from all different major manufacturers flown by multinational crews. Excursions (both takeoff and landing), whether off the end (overruns) or off the side (veeroffs), are estimated to cost the global industry about $900 million every year. Worldwide, in 2009, there were about two runway excursions per week, about half of which were landing overruns. The focus of this research is on landing overruns only.

In the 2009-2010 overrun events each aircraft landed and remained on the runway. The crews desperately tried to stop, but failed to do so. Hull loss and, more importantly, lives were lost or placed in jeopardy. Is this type of accident a foregone conclusion when the landing actually takes place in less than desirable conditions or when a minor system anomaly creates a condition unforeseen by the flight crew?

Years ago, I participated in an accident investigation involving a Sabreliner that overran the end of a runway. The inability of the aircraft to stop was, of course, key to the investigation. Due to Human Factors and systems issues, effective braking was not achieved until late in the landing roll and was insufficient to stop the aircraft. Because the aircraft maintained its speed during the roll-out, we began to wonder about whether the aircraft could have returned to the air instead of attempting to stop. While the airfield did not have runway distance remaining markers, the last taxiway available was 1200 ft. short of the end of the runway (add-on runway which would require a back-taxi if used). The question became, "if the crew had decided at that last positive position on the runway to go around, could they get back into the air safely?" Based on the airspeed calculations at the time the aircraft passed the taxiway, we asked the manufacturer to calculate a power-up and acceleration at the landing weight to see if rotation and takeoff could have been possible. As investigators, we could not perform our own calculations as the flight manual takeoff performance data did not include gross weights down to the actual landing weight (therefore, the pilot's would not have the knowledge). It turned out that if the aircraft could have applied 100% power at the same 1200 ft. remaining, accelerated to rotation and, most likely, would have been above stall speed prior to the end of the runway.

Let us be clear: (L/D)max Aviation does not propose that this scenario be followed as a "procedure" by anyone. The unique conditions in any transport or business aircraft require specific procedures be developed by manufacturers and scrutinized by operators for their flight crews. Hopefully, this research will stimulate discussion as a potential tool in the flight crew bag of tricks that may help avert damage to aircraft and injuries to persons aboard them.

Assistance is needed in these areas to further this research:

1. Specific information on landing and takeoff data for a nominal landing weight aircraft. (L/D)max Aviation is asking for the data to represent Air Transport aircraft, Business aircraft and military aircraft. We are hoping to have type-specific data to make initial assessment of the technique viability. All sources will be kept confidential in any publication of presentation about "Aborted Landings." The requested data may come from manufacturers, operators or others having access to the data.
2. Operator comments about the operational decisions and system reversions necessary to go from a landing attempt to prepare the aircraft for a return to flight.

Investigators strive diligently to find the "cause" of all aircraft accidents. That effort at times is easy as the cause factors are straight forward. But, at other times, the accident sequence is complex with many "contributing factors" that ultimately result in damage or injury. During review of several accidents in preparation for my Aircraft Accident Investigation course, we are sometimes left wondering why some "contributing factors" do not rise to the level of cause.

Example 1 - While in the weather, the aircraft loses all vacuum systems resulting in failure of all attitude references. The pilot desperately informs air traffic control of his situation asking for any clear area so he can sort it out before losing control. Unfortunately, there is no clear area available, the pilot loses control of the aircraft and it crashes fatally injuring the pilot. The cause of the accident determined by the investigative agency: "failure of the pilot to maintain control of the airplane, due to spatial disorientation." The report indicates that the primary vacuum system drive failed and the stand-by vacuum system was clogged with the seal. There is no information about the cause of the shaft failure of the primary system and no discussion about what the seal material was or where it came from. There is seemingly no investigation of the most recent annual inspection which would have required confirmation that both the primary and standby vacuum systems were functional. There was no discussion of procedures which might have answered the question about pre-flight check of, at least, the stand-by vacuum system prior to IFR flight. Why not? The precipitating events led directly to the loss of spatial orientation, yet the cause is the pilot's failure to maintain control.

Example 2 - Due to maintenance incorrectly fitting an oil line to the fuel/oil heat exchanger, the engine loses oil pressure. The crew correctly begins to divert through the weather to an alternate airfield. Eventually the engine is shut down. The failure of the crew to correctly configure the aircraft and several distractions leads to the aircraft not being able to maintain level flight prior to reaching the airport and the aircraft crashes. The cause of the accident was determined to be the "failure of the pilot to properly execute a single-engine approach and landing." Without the engine anomaly, the pilot would never have the requirement to execute the single-engine approach in the first place. While it can always be argued that training in the single-engine procedures should have made the actual event within the pilot's capability, there was scant attention to the event that set it all into motion.

Our research is not intended to shift determination of contributing factors to the level of cause. Rather, it is to suggest the appropriate weight to the precipitating event so that this initiation can be removed from the future accident sequence. In our first example, no recommendation was made to preclude vacuum pump failures or clogging of the stand-by system. In the second example, no recommendation to preclude mis-installation of the oil line was made. Therefore, these "precipitating events" remain unaddressed and without the corrective action which is the intent of quality investigations, present to become "contributing factors" again and again.

Assistance is needed in these areas to further this research:

1. Additional examples of accidents where the precipitating event was not fully analyzed or recommendations for improvement were not made by investigation agencies.
2. Manufacturing examples of initiatives taken as a result of an accident (and its investigation) without a recommendation to do so by the investigation agency. Please provide a brief overview of the accident that brought the initiative to corrective action. If a published report exists about the accident, sufficient information to allow its retrieval and review would be appreciated.

As aircraft accidents become more and more rare, due largely to efforts of investigators, there exists less opportunities to exercise the skills that develop great investigators and to improve the skills of new investigators so that they are ready for the challenge of a real investigation. (L/D)max Aviation is researching the use of gaming software and photo-documentation of aircraft accidents to distribute a virtual investigation that can be used by a single investigator to improve skills or by a group of investigators to experience the inter-relationships of investigating groups into the larger, major investigation.

Beginning with detailed documentation of a crash site and following the actual investigation through the phases of investigation to final reporting, (L/D)max Aviation is hoping to develop a training scenario that could be examined by new investigators as an interactive case study. The second phase would be to do the same for a larger accident investigation and put all the materials into a directed activity to exercise group investigations.

Lastly, it is hoped that video gaming software could be used to develop a virtual accident scene allowing an investigator to "walk" through the site, watch directed tests, and visualize the use of technical experts in gaining the best information. While the marketplace for such a process is small, we are hoping to use existing technology in a new, innovative way.

Assistance is needed in these areas to further this research:

1. Participation by first responders and the accident investigation team to fully document the accident scene, even if doing so is not required by the investigation. Additional photography, diagramming, measurements and debris field documentation is essential. (L/D)max Aviation would be willing to perform the additional documentation if notified in a timely manner and allowed on-site to do so (on a non-interference basis.) Eventually, (L/D)max Aviation would require access to documentation that supported the investigation. Information similar to the US NTSB Docket may be sufficient.
2. We are looking for computer gaming software experts who would be willing to discuss the needs and concepts to create the virtual investigation.