EFB-Pro  Letters to CAVU 




This is why EFB PRO is the best!!

On the runway analysis you actually have to manually adjust the numbers based on whether or not you have a headwind or tailwind. EFB does it for you.

Heiko Stum, Chief Pilot



I have used the new EFB-Pro and it is GREAT! It is really very, very helpful!

I really love the W&B, I am glad I spent the $!  Whats also really helpful is the Contaminated Runway Charts for Takeoff & Landing and the turn-around time calculation which we use all the time in the Beechjet 400A.

Thanks again, you have been a great help!

Kevin Oconnor, Beechjet Captain

A couple of weeks later:

Thanks again . We just finished a 16 leg four day trip while trying out EFB-PRO. We really like this program and feel that it is a great enhancement to the safety of our operation for the following reasons:

1.       It uses the Net takeoff flight path as used by the AFM. I like the KISS principle and this keeps things as simple as possible if something were to go wrong. 

2.     It is easy to use which means it actually gets used on every leg. Including landing. 

3.  It provides the limit weighs for each phase not just the most limiting one.  Really like that.




While running comparisons for departure out of Driggs Idaho I received impressive results. Both programs said it was 2nd segment limited. Ultra Nav said it was extending second segment. I ran the paper charts and EFB-PRO

 was spot on for climb required and takeoff distance! EFB-PRO also gave me an extra 1,000 lbs of payload I would have left behind using Ultra Nav.


Chris Meador
Chief Pilot




Mr. Deuvall,

I just finished reading your wonderful book on my iPad this morning (again).  Thank you so much for putting together such a fantastic product for our community.  I will most certainly recommend it to my many peers at Pegasus!

Very best regards,

James Booth

"We are convinced that the only way to properly and efficiently comply with obstacle clearance requirements is with the use of a performance calculator like the EFB-Pro.  CAVU has demonstrated to us that they are the leading experts in this area, and have gone out of their way to accommodate the needs of our flight department, and to help ensure that we are safe and compliant.  Their methods are sound, proven, and provide an easy way to navigate the difficult problem of ensuring obstacle clearance by just using the AFM alone.  Thanks for the great product and customer support.  As a charter operator, we will be using the EFB-Pro for all our performance and weight and balance needs."

Chris Palmer
Director of Operations
Maximum Flight Advantages, LLC



"I used to think that the AFM did not provide enough information to calculate obstacle clearance, and in particular departure gradients.  After reading your book, it became very clear that the information was there but needed to be 'mined out'.  Obviously, this can not be done, in any practical sense, by hand.  EFB-Pro wonderfully ties all the regs to the performance charts in a very intuitive and safe manner.  Thanks for a great product." 

Rich A., Standards Captain 



"We should have had this ages ago." 

Dennis G.




"I wanted to let you know that the program you put together for the Falcon 200 is excellent, and has proven to be a very beneficial preflight tool for our operation."

J. Scott Carr, Chief Pilot



 "I've been flying these (corporate) aircraft for over 30 years.  When our department first started, we used APG.  Even when we knew that we would get a V1 cut, we would brief to the point of deciding who would press what buttons and switches, the holding pattern entry, everything.  We have event driven FMS so I only had to press a button to switch over the FMS. When we actually practiced it in the sim, as busy as it got, it wasn't unusual for us to still mix it up. It was very apparent that this was un-doable on a regular basis on the line. Perhaps airlines that can train crew to a specific route schedule and a handful of special procedures, but its totally impractical for part 91 and 135 operators who never know what airport they will be departing from. Having to keep track of when the special procedures depart from the SID further complicates the problem.  I can't over emphasize how distracting and busy it gets, even in the sim, during an engine out scenario. Keeping track of the new routing with IMC conditions and knowing that terrain is out there is just not practical.  Crews that use APG are kind of kidding themselves or maybe intentionally trying to placate regulatory requirements that this is a safe mechanism for assuring obstacle clearance. Most crews I know that use APG don't train in the sim for the product and really have no idea what they are buying into. They get it as part of their Arinc.  And remember, none of these procedures have been flight tested." 

Steve B, Chief Pilot



"I am having so much fun with this!

The performance calculations are excellent and far more accurate and consistent that anyone can do with performance graphs. Customer support is phenomenal and the product has undergone a series of improvements in the last two months with additional features that make EFB-Pro an indispensable tool and fun enough to use that I find myself doing wild performance scenarios just for entertainment.

This would be a tremendous help if, say, the crew is faced with a difficult situation (say, pax show up with extra people or baggage and they're late and it's now really hot outside; someone at home / base can crank numbers for them and get it to them in this way (email).


Keith Gordon

Director of Aviation, Desert Jet





Bizav Training & Services, Inc.

Mr. James Deuvall                                                                   July  12, 2010
CAVU Companies
103 Burrows Road
West Winfield, NY  13491

RE:  CC of letter sent to FAA

As an instructor and check airman of turbojet aircraft for over 26 years, I have trained a multitude of pilots on the subject of performance.  I have catalogued numerous methods and observed several commercially available products that pilots have presented to me during class.  The inappropriate methods range from not performing the calculations at all, to elaborate, but incorrect, rules of thumb.  The products I have tested range from downright incorrect and deceptive, to thorough, clear and comprehensive.  Like you, I am on the forefront of promoting aviation safety and I hope you will find this letter informative.
First, I would like to mention a publication that is an excellent primer on the issues I will be discussing.  The book, which can be found on Amazon.com, is called “Aircraft Performance-Myths and Methods” by James Deuvall.  I recommend this book to all my students and even the highest time pilots find it very helpful.
The proper use of Part 25 performance charts, irrespective of the manufacturer or model, is a complex process. The obstacle clearance method discussed in most, if not all, part 142 schools, while consistent with the AFM, are wholly inadequate to the preparation of pilots flying in today’s changing environment. The reason for this is that all AFMs use, as an obstacle clearance example, the rare and simplistic condition of clearing a single, relatively short, known obstacle.  This example calculation is very straightforward and even somewhat intuitive.  Rarely is any time spent instructing pilots how to meet a climb gradient, such as a departure procedure (DP), ODP or SID.  Because of this, most pilots, as well as some vendors, use that same intuitive methodology to meet extended climbs associated with DPs.  As a result, erroneous maximum weight calculations are the rule rather than the exception.  If an operator is not using a performance calculator, I can assure you that either the charts are not being referred to at all or are incorrectly done so.  It only takes a matter of a few minutes to uncover the potentially life-threatening errors manual methods produce.
Now, I have also found that the use of a calculator, by itself, does not provide adequate assurance of correct computations either.  It is very important to understand that calculators also use a methodology and I have found that some popular calculators simply automate the same improper methods that pilots use manually.  The best known of these is UltraNav.  I have encountered this product numerous, numerous times as an instructor.  UltraNav self-proclaims and promotes, as a benefit of their product, several erroneous assumptions.  Every Part 25 aircraft, by certification, uses a specific profile to construct the AFM data.  That profile, referred to as the Net Takeoff Flight Path, is absolutely integral to the validity of the numbers published in the AFM and mentioned in both Part 121, 125 and Part 135 regulations.  In order for the aircraft to achieve the values in the AFM, the aircraft must fly the profile precisely.  If a calculation deviates from this profile, none of the promised performance, within the AFM, can be assured.  The profile requires ALL aircraft to climb, within second segment, to a maximum altitude and no higher.  There are a few exceptions however, for example manufacturers who have provided specialized charts for extended climbs while maintaining engine time limits, but most aircraft have mandatory level-offs from 400 to 1500 feet.  This is one of those non-intuitive computations typically overlooked by pilots attempting to compute performance by hand and almost universally not observed during Part 142 simulator sessions.  The intuitive, but incorrect, method would be to not lower the nose if an engine failure occurs and hold V2 no matter what altitude is required to clear obstacles. This is exactly what most simulator instructors teach and what the UltraNav performance calculator calculates.  Unfortunately, as I mentioned previously, the resulting flight path of holding second segment beyond the limits of the AFM is entirely hypothetical.  UltraNav calls this “always-in-second-segment” flight path “True Flight Path”, which they have “coined” within their product.  The validity of this path is entirely false.  Abacus and AFMsolutions (written by the same gentleman who wrote UltraNav) also make similar assumptions.
The only performance calculator that follows the Net Takeoff Flight Path and incorporates the engine-time and other system limits correctly is the CAVU Companies’ product EFB-Pro. 
The Cessna CPCalc product, while certified under the same provisions as an AFM, does not appear to follow its own print version of the AFM Net Takeoff Flight Path procedure.  If you enter a climb gradient in CPCalc, lets say a 6% climb to some altitude above 2500ft; the calculator will provide the total distance from the end of the runway to the beginning of the level-off segment.  If you divide that value into the AFMs maximum level off altitude, you will get a gradient that is less than the 6%.  This can only occur if the path of the aircraft falls below the 6% gradient during the climb or the level-off (third segment) has been initiated above the maximum level-off height.  This is an apparent disconnect between the AFM and the calculator.
The other non-manual method, which is becoming increasing more popular, is the use of runway analysis.  There are several vendors of such products available to business class jet operators, but the most popular, I believe, is APG (offered free through ARINC Direct, a factor in its popularity).  While I have nothing against the actual calculations provided, I have observed consistent misuse of this tool.  Runway analysis comes to us from the airline industry.  Within that environment, runway analysis is a safe and well-managed practice.  Airlines typically use an internal engineering department to construct “escape procedures” and flight test those procedures with “average ability” crew and standardized equipment in mind.  Line pilots are then familiarized, during simulator sessions, with the procedures they will encounter along their scheduled routes. 
Runway analysis, when utilized within the part 135 and 91 worlds, poses many unique safety issues. Unlike the airlines, who train to proficiency on a handful of “escape procedures”, the Part 135 crew potentially faces several thousand uniquely modified DPs at a moments notice. I have never encountered an operator who was required to provide, nor has voluntarily provided, enhanced simulator/flight training specific to runway analysis even when authorization was needed to use this method.  During training, what I invariably encounter are crews who refer to the maximum weight listed for a runway and then the entire process ends there.  Operators are universally unaware of the special procedures involved in using runway analysis correctly and safely.  Here are just a few that I have encountered. Since the modified procedure will most likely deviate from the normal departure procedure, crews must set up FMSs and brief differently.  Rarely, if ever, is this done.  Crews are universally unaware of the reduced safety margins, both laterally and vertically, utilized in constructing the unique runway analysis DPs (AC120-91).  I have never seen an operator actually flight test the procedure, as the airlines do.  Briefing points should include items such as when the DP procedure becomes obsolete (The point where the modified DP deviates from the normal procedure. When the aircraft passes this point, the aircraft is committed to the normal procedure).  Since the FMSs maybe set up independently, one for the SID, the other for the modified DP, a thorough understanding of who will be the pilot flying (PF) must be briefed in the event of an engine failure.  Routinely the modified DP will incorporate a hold, the location and entry of which must be briefed.  Additionally, the method of navigating must be considered since wind drift may lead to a flight path that lies outside of the safety area.
As inspectors and examiners, I am aware that you can not advocate the use of specific products as I am at liberty to do; however, I would encourage you to contact me and/or acquire a copy of the aforementioned book to learn more about this area of flight safety that has gone largely unnoticed by the industry.  I should also mention that in no way do I financially benefit from any of the products mentioned.  I am sharing this information with you as a professional pilot and instructor devoted to the continuing safety of general aviation.
With regards,

Darrell Rahn

(Reprinted from NBAA Airmail )


You offer a good opportunity to bring a different, and I think more important, perspective to this.  The "battle" between APG and EFB-Pro (that seems to be the two camps these days) is not which one has the most features. Though none come to mind at the moment, I'm sure CAVU has its fixes to make too.  My goodness, I have a $500K avionics suite that keeps needing "upgrades".

Mr. Gordon hits it on the head with his last question, but he's only hinting (perhaps out of politeness) at the real issue.

This is a difficult subject to approach since any comment I make may (and probably will be) be construed as bashing APG.  So let me say up front, I don't care which system you use; I only refer to them by name because everyone seems to understand what I am referring to when I do. I'm really referring to the whole runway analysis approach.
I have found, even in my own department, that there is an underlying difference in, what I call, a "perception of importance to safety" between pilots/operators who support APG's approach versus those who do not. The difference fills the spectrum from those who run the numbers only to justify filling the airplane up to max gross to acknowledging that there is a safer way but "we get it free with ARINC and besides our POI has approved us to use it".  Across the board there seems to be a sort of level-1 thinking only, ie "APG says we can go out with this weight, thats it, end of discussion" when in fact there are several very important, even life-threatening, issues dealing with the actual logistics of implementing the use of special DPs.

First, it should go without saying, you don't get anything for nothing.  If you go out heavier at any airport OEI, physics dictate that you will be lower to the ground. APG is not a magic wand.  Your obstacle clearance will be less and your left and right obstacle clearances will be less (way less) than the normal departure.

Second, you mention Rodger Hemphill and his wealth of knowledge. I'm sure that is true, but no one that I've talked to there was one.  There's a big heap between an engineering a departure and actually sitting in the front seat, on a rainy day, mountainous terrain and an engine fails.  Even in the sim, it can get your heart pumping.

 Third, there is a big difference between 121 and 135/91 operations.  I seem to get the most push back from guys who come from the airlines who believe this is the way it should be done.  But wait, I've flown for the airlines. Every 6 mths I was back in the sim training on the "escape procedures" I would encounter on my route and at most there were like two.  In fact, the crew had to be checked off to use them.  Plus the company had flight tested all the procedures with our own equipment.  That kind of validation is not done by any operator that I know of.  I've never heard anyone come up with a good solution to the training proficiency issue.  We barely have time to cover one special DP in the sim and most of the time the instructor is not familiar with the special DP and basically just positions us at the end of the runway.

Fourth,  all the special DPs had to be manually entered in a second FMS.  The FMS I use has event driven switch-overs and still it takes 4-5 seconds while my side side refreshes with the routing from the other side.  4-5 seconds may not seem like a long time, but it seems like an eternity when things are hitting the fan and happening fast without any nav reference.  Referring to the post on over automation, it seems that automation always seem to fail at the worse time.

Fifth, briefings.  With 30 pilots in our department, I can say the standardization of briefings of dual departures with an immediate hold is a pipe dream. Here's an example, on the APG print out, a level height is sometimes given to you.  The problem is its a "fixed" MSL value.  So crew would brief this altitude to level-off. Do you remember "high to low, look out below"? When you are dealing with altitudes in the 400-1500 ft range, these things matter.  One reason we went with EFB-Pro is that their level-off altitude is corrected for temperature and pressure differences from ISA.  We can actually brief that number, but I digress. 

There are many more issues and stories but let me end with this.  Several years ago, we came out of Vegas in a global.  The boss wanted to go non-stop London.  Problem was he wanted to leave at four in the afternoon in the middle of the summer. I ran the numbers using EFB-Pro and my co-captain looked up APG numbers.  To make a long story short, I determined we had to make a stop or go when it was cooler.  The owner, who wanted to go when he wanted to go had been told by his "friends" that they do it all the time in their globals, and my co-captain!!! both argued with me.  I prevailed and departed without incident on the 14000ft runway.  After leveling off, the owner stuck his head in the door and said essentally, "Thank you for sticking to your guns.  Even sitting in the back, I could tell how long it was taking to get airborne, in fact I was getting a little nervous about it and that with both engines running. I spent $40M on this airplane and its an eye opener to see how marginal the performance is."  Again, a "perception of importance to safety".  In the final anaylsis, what are we really relying upon for our safety.  Unfortuately, for a number of us, it appears to be the reliability of the engines.

 I'm sure this will tip off a firestorm of comments, becasue people are passionate about what they have, but I have come to the conclusion that using runway analysis, practically speaking, only has a very limited use in 135/91 operations and even then only with specific proficency training and SOPs in place.


Jeff M

Standards Captain



















Coby Johnson, Manager                                             March 3, 2007
Flight Operations Branch, AFS-410
Federal Aviation Administration
800 Independence Ave., S. W
Washington, DC 20591

Dear Dr. Deuvall

In response to your presentation dealing with preflight takeoff calculations, runway analysis and obstacle clearance, I would like to take this opportunity to thank you for taking the initiative to shed more light on an area of aircraft performance that has accumulated a great deal of confusion over the years.

While the FAA can not endorse a specific product,  I can speak to the FAA’s position regarding the authority of the aircraft flight manual (AFM) in conducting preflight planning calculations.

First, allow me to dispel the notion that the AFM contains takeoff procedures that have been included for certification purposes only and have no operational relevance, particularly preflight planning. 

The profiles described within the AFM are considered by the FAA to be the only acceptable procedures. 

Second, if the AFM describes a takeoff path profile, including level-off or transition periods, engine time or other limits, those criteria must be considered when calculating appropriate engine inoperative obstacle clearance performance planning and weight restrictions.  This is particularly true for obstacles or gradients that extend above 1500 feet.

Third, the use of “rules of thumb”,  “work-a-rounds” or other methodologies not specifically described within the AFM or subsequently authorized by the manufacturer are not approved by the FAA.  This would include, but is not limited to, extrapolating performance values beyond the limits of a chart or substituting an enroute altitude for the airport elevation when entering a second segment chart.

While none of these clarifications diminish the pilot’s authority to deviate from any regulation to meet an in-flight emergency, the intent of this position is to improve the safety margin of all operations operated under commercial or general regulations. 

Again, whether you are presenting to Part 91, 135, 91k or 121 operators, please extend my appreciation for their continued efforts to improve their skills and knowledge as professional pilots.

Thank you

Coby Johnson
Manager, AFS-410

















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