Just Culture Accident Model

This paper proposes that the concepts developed for Just Culture may provide an avenue to broaden the scope of accident investigation and move away from the “blame” outcome of most reports through the use of a simple Just Culture algorithm to mitigate cognitive bias on the part of the investigator. Absent a formal strategy, cognitive bias has a high probability of occurring, and becoming integrated into the investigators subconscious during the early stages of an accident investigation. Just Culture is becoming widely accepted, and as such the transition to integrating an investigative model utilizing the concept should be easier to implement and may encounter less political push back than some of the more complex approaches proposed in recent years, yet still provide a robust path to causality and human factors aspects that is more comprehensive than that offered through the traditional models that are still in use by most organizations.

Click here to view the conference paper.

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High Altitude Flying and Radiation


There is much concern in the pilot community of the exposure to radiation as a consequence of high altitude flight.  There are FAA and NOAA pages that discuss the issue and the amount of radiation can even be tracked.  So, how much of a risk is there?

The truth is, nobody really knows, so the basic assumption is that we limit it as much as we can no matter what.  However, that does not tell us much about the actual risk.  There have, though, been several large studies of the issue.  It turns out that of all things that pilots die of, the types of cancer that would be a consequence of higher altitude flight is not one of them.  In fact, several large studies have shown that pilots have a lower rate of the types of cancer that would come from exposure to radiation at high altitudes.  What do pilots die more of?  Two things, mainly.  Melanoma and kidney disease.  Now kidney disease is attributed to not drinking enough water.  Flying dehydrates us, and we need to ensure we drink enough water to offset that effect.  Melanoma comes from being outside in the sun.  It is generally attributed to the fact that pilots do not spend 160 hours or more  indoors in every month.  While some studies indicate that the melanoma risk cannot be entirely attributed to our “outside” activities, there is no evidence that it is from flying either.

Now there have been studies that show higher rates of breast cancer for women (cabin crew), but it is not clear why that is, and one study found that the increased risk of breast cancer was associated with the length of employment prior to 1971 – before the operation of jet aircraft by the airline in the particular study group.  In another study it was found that the correlation was mostly due to fewer pregnancies later in life, although that does not fully explain the differences.

Now, as pilots we are charged with managing risk.  How much risk do we add by choosing to fly at lower altitudes with more exposure to weather, plus burning more fuel so we have less margin on arrival?  Those are real risk factors that are proven.  High altitude radiation risk, by all accounts, is relatively negligible.

So, is there some increase in risk?  Possibly a marginal increase, but it is very small if at all.  Other factors are larger risk factors, such as choosing to eat red meat or smoking, so if one is really concerned they should target those first.  Flying higher (within performance margins) can save fuel and, as I’ve outlined in previous articles, allow for better weather avoidance.  I know which one I choose!

For more information here are a few articles on the topic:





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How much fuel?


Fuel.  It is an ongoing issue.  We all want to ensure that we arrive with enough fuel at the destination so we have options.  The best way to accomplish that is to have more fuel on departure, right?   Well, maybe not.  It turns out that is really depends on the type of aircraft we fly, and if we are flying big airplanes the issue is a bit more complex than just how much gas we have when we takeoff.

Now, we all agree that there is no question that we must have enough fuel to be safe.  We also agree that there is no question that the Captain is the final authority as to how much fuel that is necessary to meet that required.  No question.  This article is not about telling you how much to carry, but rather to help you make an informed decision.

How much fuel is enough to be safe?  Is it a number in pounds or time?  Ah, now we get to a real issue.  As a Captain, the pounds of fuel (aside from limitations for your aircraft or possible company specific requirements requirements) is actually less important than time.  The concern here is that picking a number of pounds as “safe” may, or may not be safe.

A performance analysis of fuel required for airplanes of B-757 size and larger showed that the amount of “time in our tanks” is about 50% more at a lighter weight as compared to max landing weight.  I did not run the numbers for “smaller” jets, but I would expect a similar outcome.  Weight makes a huge difference in the burn rate, so if we are just using a pound or kilogram value for how we assess our fuel quantity we can be wildly off of what we think we have, either more or less than what we are attempting to accomplish for safety of flight.

What can be seen is that when we are at a light weight we actually have about 50% more time in our tanks than we do if we are heavy.  The other thing that becomes clear in all this is that adding 2,000 pounds if it is only 4 minutes may not be enough to be helpful, particularly when one considers that we are burning perhaps 10% of that amount just to carry the extra weight.  As pilots we have safety as our first priority, but we do directly benefit from making the airline more efficient also.  Having more fuel is also not always more safe as it can adversely impact performance during takeoff and cruise.  It can make the difference between cruising over the top of the weather or slugging through it and deviating constantly thus burning more fuel than we added to “be safe”.  These are the decisions we are paid for and knowing how much fuel you have, in time, is your best path to ensuring you are carrying the amount you need.

One way to frame the thought of how much fuel over destination might be to consider how much time do you want to give ATC with a Minimum Fuel advisory call?  Recognizing this is a dynamic number and would be different for EWR, HKG or PVG on a bad weather day compared to TUL or PEN on a pleasant afternoon.  Let’s say we choose 30 minutes of fuel remaining as when we declare and emergency to get on the ground NOW (I’m just using this for a demonstration, I might very well declare an emergency sooner depending on what’s going on!).  Using typical performance values for the larger jets, 5 minutes of fuel equates to 17% (but for easier mental math, round it to 20%) of the amount of fuel it takes to hold at 30 minutes.  What ever values of fuel weight as compared to time you have, you can use that as a baseline to calculate what you are really adding in terms of safety margin in minutes.

If we use these values or something close to it and add fuel for a go around we may be giving ourselves a reasonable margin for safety and allowing for contingencies without creating a crisis in the middle of a busy arrival sequence, but remember again the potential for burning more of it enroute due to the weight of carrying it plus the higher fuel burn when stuck at lower altitudes.  The tops of the clouds, the winds and the potential for direct routing as we get over the bulk of the traffic are all factors to consider.  It is entirely possible to have more fuel at the destination by starting out with less on departure in many scenarios.

A few years ago I was headed from MEM to MIA.  There was a wide area of weather with imbedded thunderstorms enroute.  As we all have seen, when flying through the weather in an area like this it can be a challenge to pick out the storms from the general rain in the area.  Dispatch had put on plenty of fuel so we could weave as necessary on our way to MIA.  As a result of the amount of fuel we were limited to around FL310 due to the weight.  I noticed that the tops were not above FL350 with few exceptions so I did something that might seem counter-intuitive. I asked for less fuel.  Enough less that we were able to climb to FL370 and sail over the top with just some very minor visual deviations along the way.  Do you think I landed with more or less fuel than I would have if we had stayed on the original plan?  Comparing the flight plans our burn was significantly less even without deviating.  A similar outcome might happen on an Atlantic crossing, where adding more fuel might mean that we are unable to get a higher altitude on the crossing resulting in burning through all the fuel we added and more, and actually landing with less than if we had not added any fuel at all!

Again, it is a complex scenario that must include considering many factors. Weather, tops, winds, aircraft performance, the effect on traffic based on the time of arrival (which in turn is impacted by the other decisions).  Each flight is different and it is up to us to consider all the aspects.

Regardless of the decision made, remember to always to keep the flight dispatcher in the loop.  They share legal authority and regular communication is not only smart but is also required by regulation.

Posted in Safety

The Bluecoat Project

If you’re on LinkedIn, check out The Bluecoat Forum
An international Forum on the subject of FMS, EFIS and EICAS displays, automated subsystems, flight mode annunciators, flight directors, autopilots, and the integration of all avionics equipment in the modern cockpit.

Posted in Safety

The Briefing

I just thought I’d share something fun.  Pilot briefings are very important, and it is critical that these are, literally, “brief”, as well as hit the issues that are actually important.  Things that are just standard and expected are not helpful to include as they just distract from the core points while the person receiving the information tunes out to those aspects.   These are videos clips from the British show “People Like Us”.  The first illustrates a departure briefing, and second an arrival briefing.  Enjoy and let me know if you like these briefing styles.   Do they fit the description above?  Comment below! Click on the images below for the video.

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Angle of Attack book released!

AoA book image

Finally, the definitive book on the Titanic of aviation accidents, a state-of-the-art jet that couldn’t stall until it did and took the lives of 228 Air France passengers and crew. Based on exclusive interviews with the aircraft’s manufacturer, the airline, flight crews, families of the pilots, accident investigators and the Woods Hole led team that recovered the missing jet from the bottom of the South Atlantic, Angle of Attack reveals why airlines and regulators everywhere must respond now to critical lessons from this legendary event.
Autographed by Shem Malmquist only contact me here.
Autographed first edition copies available from Curt Lewis Aviation Books at
Buy the book and the movie, Pilot Error (a fictional movie based on a similar event), Pilot Error, and save $6
“We owe Rapoport and Malmquist a great debt of gratitude.  Read every word.”
-Dr. Gary Helmer, Embry Riddle University
“A great resource for aeronautical professionals … exposes the failed defenses that can reside at each layer of the aviation system.  A must read for anyone with an interest in aviation accident investigation and aviation safety.”
-Dr. Chris Johnson, Director of Aviation Education and Research, Industrial & Systems Engineering, University of Wisconsin, Madison
“A must read for professional pilots, aircraft designers, government regulators and political decision makers.”
-Gregory Fox, Director of Safety, Florida Institute of Technology, ATPL pilot, safety manager since 1971, 35 years safety regulator, and 20 years check inspector on A320 and A340.
“Angle of Attack sheds light for the novice and expert alike.  Their subject matter expertise is admirable.  They have used the Air France 447 crash and other crashes of automated airplanes as examples of accidents that might have been prevented if the crews had access to realistic training to prepare them for those rare events and if their aircraft had been equipped with angle of attack indicators.”
-Captain Elaine M. Parker, Beyond Risk Management
“For the very first time the full story of Air France 447, one of the most significant events in aviation history, is revealed thanks to eight years of painstaking research.”
-John Darbo- Argus International, former American Airlines manager of internal evaluation and event investigation.
“You don’t have to be a [pilot to find this book moving and absorbing.”
– Adam Hochschild, Author of Spain in Our Hearts and King Leopold’s Ghost
“This book proves conclusively that education by meteorologists is the key to fundamental understanding of the impact weather has on the elements of the aviation arena.”
– Debbie Schaum, Embry-Riddle University
“A masterful work that was hard to put down.”
-Captain Shawn Pruchnicki
Ohio State University for Aviation Studies
Posted in Safety | 3 Comments

A dry microburst experience

virga photoI came across this article today which I had written quite a few years ago.  How many years ago?  Well, TWA was still in business!  I should add that my more recent article, here, is a worthy follow-up if you’ve not read it, as is this one. That said, here is the article, as originally written.:

At least once each year we each return to fly the simulator.  The “game” in the simulator is fairly predictable.  We know what to expect most of the way through – we are more surprised when something has not failed or gone wrong than when it has!  Although the simulator ride itself is fairly predictable, that probably does not significantly detract from the experience, and we will carry our training to the line.  This is largely true because we are really practicing the procedures themselves as much or more than how to fly the airplane.

So, here you are, flying the simulator, and the instructor tells you that windshear has been reported in the area.  You are now spring loaded to go for the recovery and at the first indication of windshear you go through the escape drill.  But how much is this like the real world?

Recently I was discussing this issue with a friend of mine, TWA. Captain Steve Holmes. Steve also teaches in the simulator for TWA.  It turned out that we had each encountered a dry microburst on approach, and coincidentally they were while flying into the same airport, Salt Lake City (SLC).  Another thing that both of us found similar was the insidious nature of the encounter.  Our experiences were virtually identical.

Approaching the Salt Lake area there were some buildups in the area, along with visible VIRGA.  The conditions at the airport itself looked fine, so we continued the approach.  No windshear had been reported.  On final the air was smooth and as we descended on the ILS in virtually unlimited visibility all seemed normal.  The microburst did not slam us all at once, unlike what I have usually experienced in the simulator.  Instead, I found that we kept getting a little bit slow, so had to add a bit of power.  Not a lot, just a bit, but after a while we had a whole lot of power.  At some point it became clear that things were not right and a missed approach was executed on short final.  The aircraft performance on the go-around was sluggish to put in mildly.  Go around power and we just barely held altitude until near the departure end of the runway.

The point here is that it was not immediately clear that this was a windshear encounter.  Captain Holmes and I both felt that it was almost like being “sucked in”, in that everything felt and seemed fine until we were fairly committed to flying through the event.  In both of our encounters we felt that we were directly under a newly developing microburst, so encountered the decreasing performance portion only.  He found it particularly disturbing that it could be so easy to get “sucked” into this type of situation as he trains crews to avoid and escape from such encounters in the simulator.  He is very familiar with the procedures and warning signs.

It might be possible to train windshear differently, but that is not the purpose of this article.  It is simply not possible to train for every possible combination of circumstances we are likely to encounter. The responsibility for a safe operation will always rest with the flight crew, and it is our knowledge and experience that keep flying safe.

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