Flight Data Recorders are Where You Find Them

A very tragic story is unfolding in British Columbia surrounding a hang glider accident that resulted in a young woman falling to her death instead of enjoying an adventure gift purchased by her boy friend. Apparently included in the package was video an pictures documenting the flight. As I have previously written about a Vans RV 7 in flight break up, video or pictures recorded during a flight are a valuable resource to accident investigators, and proves to be surprisingly durable. In a strange twist, the pilot of the ill-fated hang gliding flight apparently thought there was something on the video record that he did not want to come to light. It has been reported that he swallowed the data card containing the video, resulting in a charge of obstructing justice.

When considering the cause and responsibility for an accident it is important to try to remain impartial and detached until all the facts are in. We will have to see if the data card survived the trip through the pilot's digestive system, experts are confident it has. Then we will have to see what evidence, if any, is in the data. However, the fact that the pilot took the rather extreme measure of trying to destroy the card by swallowing it is telling. It is certainly one of the stranger stories about flight data recovery that I have ever heard.

My condolences to the friends and family of Lenami Godinez. To lose someone during what should have been an enjoyable adventure to what certainly looks like a preventable accident affects everyone in aviation.

One Duck, or Two?

As I move through the story of my personal experiences with CASARA, it is important that you know something about some of the other players. This is a story told to me by the person who was acting as the mediator in a dispute between the unit director and I. I should have taken it as a cautionary tale, unfortunately I didn't.

This person has relatives who have oriental ancestry and celebrate culturally important days with traditional foods, in this case duck prepared by a local small business. My erstwhile mediator decided that since the family was large and there would be many people sitting down to dinner there should be two ducks. He was told that was impossible. The supplier, possibly because demand far outstripped their ability to supply, had a one duck per customer rule. "Not a problem, just wait, you'll see" he said.

There are a number of ways one could solve this problem: Find two suppliers, Learn how to prepare the duck at home, Try to convince the proprietor that the size of the festive gathering justified two ducks. None of those were tried though. Our hero simply told the proprietor that he would be attending two dinners, and was responsible for procuring a duck for each. This still took some convincing, but eventually two ducks were ordered, and in the fullness of time picked up and enjoyed.

So, what is the big deal? A little white lie won't hurt anybody? Well, just the family that might otherwise have gotten duck number two, but had to do without that year. Or maybe the proprietor spent more time and effort to prepare an extra duck. Time that could have been spent enjoying the festivities with family. The big deal, to my mind, is the ease with which the truth becomes mailable in order to achieve a personal goal. This story, what eventually transpired during the mediation (which I will get to) caused me to re-evaluate some of my previous experiences with this person and completely change my opinion of him.

What was really surprising is that when I talked to my wife about this, she said she had known that about him for years and it was one of the reasons she left CASARA in frustration when she did. Go figure. When in doubt always check with the wife.

Condolences to the Friends and Family of Geoffrey Leech

Geoffrey Leech was found today after having gone missing on April 17th. A massive search was conducted including members of the Rideau Ground Search and Rescue Team, many of whom I know from other community activities. Unfortunately he was not found in time. This does remind us that when you volunteer to assist those in need, you never know when your services and skills will be called upon, keep them sharp.

An honest mistake?

Until now my posts about CASARA have been quite technical in nature. Now I'm going to start on the management, governance and leadership of CASARA.

We have seen how three members,one the zone commander, used false data to develop and substantiate a new search technique. I call the data false because I have no other word for it. The equipment they used was, by design, not capable of producing the data they claimed and reported. A professional analysis of recordings they made and provided to me also demonstrate that the claims they made for the data were false. How could this happen? Well one explanation I think fits the circumstances is that many of the members of the unit involved are in thrall to Dr Muir's academic credentials. At one point Mike Casey said to me that "Langley is smarter than God, he has been everywhere and done everything". How does one counter that level of religious fervour? I have provided all the same technical data to them as I have published here, I have also kept the key figures informed each time I published a new post. Lately a court judge and a police officer accepted an argument based on physics and agreed a motorist was innocent of a traffic offense. But it seems listening to scientific arguments is beyond CASARA even though they are quite prepared to use Dr Muir's PhD as justification for believing just about anything he says, regardless of how unsubstantiated it is, or whether or not the data can be verified.

One example of this is that Dr Muir expressed concern that members without sufficiently acute hearing may not be able to perform the Cardinal Pass. As a result, anyone who correctly interpreted the audio as having no useful information and was not fooled by Dr Muir's assertions would be labeled, sadly, too hearing impaired to perform the technique. Is CASARA poised on the cusp of membership eugenics fueled by quasi religious mania? Perhaps, perhaps not; but I do know that if you disagree with your zone commander, even if you have science, engineering and professional qualifications on your side, you're on the short track to the rubbish tip.

Another example is that when an operator mishandled an iPhone when capturing a GPS fix, Dr Muir declared that there was an obvious unknown datum error and stated that he had gone to Google Earth to make up a replacement. More false data. It was certainly not a datum error, unknown or otherwise. It was the work of a few minutes discussing the issue with the iPhone operator to determine that she was simply in too much of a hurry to get a good fix.

Are these honest mistakes? Normally when someone makes an honest mistake, once it is pointed out they try to fix what they have broken with their mistake. Are these the results of someone trying to show off knowledge they don't have? Are they the result of ignorance feeding ignorance? Did each of the three think one of the other had the expertise and so the whole thing spiralled out of control? Search and rescue missions require the crews to honestly and accurately report the results of the search. Whether by mistake or design, that is not what happened in this instance. So many questions, but I have even more.

When you are the training officer, responsible to ensure the members are trained in the use of effective techniques, and you find out that some members (including the zone commander) have been carrying out private testing of their new completely ineffective invention; what do you do? When you then find out that they have been using it on evaluations, and on actual SAR missions when peoples' lives could hang in the balance; what do you do then? I'm interested in answers from anyone who would care to share, but I'm most interested in answers from CASARA members.

Spot Checked and Rechecked

Back in 2008/2009, when the Spot Satellite Personal Tracker was relatively new on the market, a number of authors reviewed the device and service. Opinions were not particularly good, and deservedly so. The user interface of the device was kept intentionally very simple, to the point of making it difficult to use without either developing an intimate familiarity or a check list. The reliability of the data link was not particularly good especially under circumstances that outdoor enthusiasts would consider common when a device such as the Spot may be most desperately needed. One article, first published in Kitplanes Magazine (subscription required) and later republished in SARSCENE Magazine, even compared the Spot to two alternative technologies: 406 MHz PLB/EPIRB/ELT, and satellite telephone. If you looked at this kind of technology at the time, what ever your decision, there are two important reasons to have another look. First, the technology is always improving and there are new and affordable products on the market; second, the basis of comparison of the three technologies in the Kitplanes article was incomplete.

New Products or Services

Spot

Spot LLC must have listened to some of the criticism because they have released hardware with an updated user interface and potentially better performance. 

406 MHz PLB/EPIRB/ELT

406Link from ACR Cobham now allows owners of at least some 406 MHz beacons to test the functioning of their equipment. With the basic service you can "test your beacon multiple times through the Cospas-Sarsat satellite system! You'll get peace of mind knowing your beacon is working properly with self test confirmation messages sent to your cell phone and email." With the plus service you get all the capabilities of the basic service plus "the added features of multiple SMS and email messaging (up to 5 contacts), trip planning and GPS test location..." Newer GPS enabled PLBs will also allow you to hyperlink a map of your GPS location.

This is a very interesting service, and has some of the same features offered by the Spot. However it makes use of the self test message protocol of the Cospas-Sarsat system so can not really be considered a full competitor to the service offered by Spot. It will however let you know that your PLB is working by closing the loop. More importantly it will let you find out if you will be able to summon help from you favourite camp spot or stretch of white water; or if you may have to somehow get to higher ground in the event of an emergency.

Satellite Phone

Iridium has partnered with Twitter to provide micro-bloging support to their satellite phone users. While not specifically an emergency notification service, a satellite phone can be used to call for help. If you have been keeping your friends and family up to date with your progress along the way even a poor quality, prematurely terminated phone call can get help moving your way more quickly. Your actual location where you need assistance is, of course, the most important information you need to communicate. But often knowing your planned route and where things were last OK is all rescue teams need to get to you.

Iridium Based Trackers

The Track24 Packetmaster series provides world wide position tracking and emergency alerting through the Iridium satellite system, as do the Nal Nano Shout and the inReach, each in their own way. There are probably others.

Recommendations?

I'm not going to make any. I don't have access to all of these systems, and if I did my test conditions and usage probably would not be close enough to yours for a proper comparison. When choosing emergency equipment there is no substitute for doing your own proper research. Talk to people who are active in the same areas and pursuits you are. Read reviews in magazines and trade publications. But always be sceptical, especially of recommendations or comparisons.

Dubious Comparisons

Which brings me to my second reason. In his article SPOT, Checked Dr Langley Muir did a reasonable job of informing his readers on the benefits and failings of the Spot Satellite Personal Tracker. He then went on to offer as options two of the other technologies I have also discussed: 406 MHz emergency beacons and satellite phone. Also well and good. But, he goes so far as to compare the technologies on the basis of frequency and power stating "The five-watt signal ensures that messages will get out unless you are in an extremely bad position. If you push the button, a full SAR effort begins;..." What is an extremely bad position? I suppose if one were to define an extremely bad position as one where a 406 MHz beacon is not able to get a signal out to Cospas-Sarsat, then Dr Muir's assertion is accurate enough. But then it is also a meaningless tautology. Power is not the only, nor necessarily the most important factor in determining radio link reliability, especially when comparing different services.

If I may digress for a moment to make a point. The Bugatti Veyron has an engine rated at 987 break horse power and boasts a top speed in excess of 400 km/h. The Oasis of the Seas has six engines totalling 130,110 horse power but can only manage 41.9 km/h. Clearly horse power is not the only factor in determining the speed of a transportation system. I am neither an automotive engineer, nor a naval architect but I know that there are many factors that come into play when determining top speed, some of which I have probably never considered or heard of.

Radio communications link reliability is similarly subject to many factors. If you are interested, and up to the mathematics there is a very good tutorial published by Charan Langton of Loral Space Systems. If I have any recommendation I would say be dubious of anyone who offers over simplistic comparisons. I will make one suggestion, watch the CBC Documentary The Trouble with Experts before acting on any recommendations; especially if your life may depend on your decision.

Young's Double Slit Experiment Aparatus on a Water Budget

I've been asked to prepare a presentation on a number of topics including multi-path induced fading. I wanted a practical demonstration and remembered Young's classic experiment from my collage days. I don't exactly have access to that kind of apparatus anymore. The Internet to the rescue! There is an amazing teachers reference which includes a way to make optical diffraction slits at home. It works very well. Now I just need something to hold the laser pointer and the slide. I'll post some pictures when I can get a stable setup.

SAR Proficiency Knocked Into a Cocked Hat

Recently I was explaining the Aural Null search techniques to a 'lay' person. Someone with no particular knowledge of radio, navigation or Search and Rescue. When I was describing how the geometry for Procedure B works this lay person quite correctly identified the procedure as finding the circumcircle of a triangle:

We discussed that regardless of where the three points were located, so long as they formed a triangle the bisecting lines will all meet exactly at the centre of the circumcircle, the circumcentre, of the particular triangle they form. If you have a difficult time believing this there is a very good animated site at Math Open Reference that will allow you to move the three points around and watch what happens.

We then looked at a diagram from IMPROVEMENT IN POSITION ACCURACY For ELT and VISUAL SEARCHES by Barr, Casey and Muir (which I've quoted from before), shown here with the original caption:

Details of the flight path (in black) very near the target. The distance between the actual position (A-ELT) and the reported position obtained using the Cardinal Pass method (REP-ELT) is 0.12 nm. The graphical solution is also shown with the most probable location (graph-ELT) being within the “cocked hat”. Note that without a GPS, getting accurate fixes on the waypoints would be impossible as would the necessary graphing while in the cockpit of a small aircraft. The blue squares are 1 km x 1 km.

The question as to what a "cocked hat" was came up. For those without salt water for blood, in the context of navigation a "cocked hat" is the triangle that forms when three lines of position are plotted on a chart. It comes from the shape of the hat worn by naval officers at the time the phrase was coined. A line of position is a partial result of a navigation fix. One example is a bearing to a known location. The captain of a ship may take a compass bearing on a known lighthouse. From that the captain knows the ship is located somewhere along a line drawn from the lighthouse along the reciprocal of the bearing. The distance from the lighthouse may be estimated, but not with acceptable accuracy, so the captain only knows the ship is positioned somewhere along the line. Two or more lines of position are needed to 'fix' the position in a single location. The size of the "cocked hat" gives an indication of the errors accumulated in the bearings and drawing the lines on the chart.

However, finding the circumcentre of a triangle the only possible cause of a "cocked hat" is in drawing the lines. No matter what errors were made in determining the three points or plotting them on the chart, as long as they form a triangle all bisectors must intersect at one point, the circumcentre. If you examine the chart closely you will notice that the line between points ELT2 and ELT3 is not exactly horizontal. The perpendicular bisector of that line should not be exactly vertical, as it is. If this line was draw accurately the "cocked hat" would be much smaller than it is, if not eliminated. If these lines were drawn while airborne in the cockpit of a small aircraft this level of error may be acceptable. This diagram was produced months after the flight using a computer. Did the authors not understand that the perpendicular bisectors were not lines of position and therefore should all intersect at a single point if drawn properly? Or, did they not care that their geometry is sloppy? I'm not exactly sure what the authors thought this "cocked hat" means; but, as my conversation partner observed, it certainly clearly indicates the amount of care an attention they think is appropriate when producing a paper meant to describe a procedure that could have a life or death impact on someone.

For those who are interested, the lines of position for an Aural Null would be circles, each centred on one of the points (in this case ELT1, ELT2 and ELT3) and each with a radius of the distance the ELT could be received by the search aircraft. Unfortunately these points were collected with the receiver tuned to 123.25 MHz (the beacon was on 123.1 MHz) so there is no way to even estimate what the reception distance might be. These points were, in fact, re-purposed from a flight on which the crew used the Cardinal Pass (which is where the MaxLat and MaxLong points come from). Even though they claim this is a "standard Aural Null B procedure", off tuning is not described as part of the technique in the CASARA Training manual. With this kind of sloppy workmanship put forward as the standard it is not surprising that the Aural Null procedures have acquired a poor reputation, and proficiency has been knocked into a cocked hat. A turn of phrase that has nothing to do with navigation.