Citation Crash NTSB Preliminary Report Farmington CT N560AR

LINKS:
NTSB Preliminary Report: s3.documentcloud.org/document...
Oroville Citation Crash Blancolirio: • Oroville Citation Acci...
Learning The Finer Points: www.learnthefinerpoints.com/
Patreon: www.patreon.com/user?u=529500...

[@roadgeneral]

It’s very easy to tell that Juan has many, many hours of flying time. So focused and thorough; he knows a tremendous amount about a lot of aircraft. I just love his analysis.

[@jimsteinway695]

What I like about Juan is he has so much aviation information in his mind, he has to page through his memory to access the information for the particular item he’s talking about. He has to pause to figure out which terabyte the information is on. As a parent it reminds me of a young child trying to make up a story. Two similar looks two VASTLY different situations. Juan is a walking aviation Wiki. Thanks Jaun.

[@HoundDogMech]

@@jimsteinway695 I Believe that hs Hesitation is a well developed of ENGAGE the BRAIN before engaging the Mouth. A feature that (In the words of one of my old TI's at Chanute AFB in '65 would say) It would 'BEHOVE YOU TROOPS' and many Politicians and us to accomplish.

[@MajorCaliber]

Juan was trained by the best: United States Air Force... (fka US ARMY Air Force), with an unbroken chain of excellence and innovation going back to the earliest days of powered flight. His airline is lucky to have him. OTOH, many at the controls of today's bizjets and turboprops went to Joe's Flight School, in Podunk, and just did NOT have the safety and PIC discipline drilled into them. (If no one YELLED at you during flight training, you are vulnerable to... doing the wrong thing, at the wrong time... pity.)

[@CRSolarice]

I prefer not to slather all over the place with slobbery praise and overly emotional sentimentality. Juan definitely knows as much as anyone, if not more, about aviation topics but in my humble opinion he needs to work on his presentation just a little in order to take it to the next level. Sometimes the stop and go recitation gets to be a little frustrating and while it boarders on potentially being a significant part of his style I'm of the opinion that he may need to relax just a tiny bit during his presentation and it would be a significant improvement for him; maybe he simply needs to rehearse his lines once or twice before doing a take or even repeat his lines in the mirror in order to make a vast improvement for himself. He's still my favorite aviation authority no matter how much he rehearses before his 'takes' and of course its his business how he runs his show, not mine. I always seem to have more critical thoughts towards the flood of slavering, kowtowing hangers on that constantly emote all over youtube; compliments are one thing but America seems to be so choc full of effusively sentimental, thin skinned wussies. Seriously, sometimes the comment sections of these videos read like cheap, overdone romance novels.

[@roadgeneral]

@@CRSolarice Since when is praise for doing a great job a negative thing. Hey Karen, if you can’t say something nice, just pass on by. Nobody wants to read your negative comments.

[@brendaanddangray7328]

Something to consider. As an aircraft mechanic I have observed this sequence several times. Aircraft taxies to the GA ramp. Sets the parking brake. Locks the airplane and leaves. Several hours later the line crew has to relocate that aircraft. They hook up and as the they are able to move the aircraft they start the tow. Soon they notice that the tug is slowing down and very soon after they realize that the brakes are set. That is when I get a call! If we can’t get in touch with the owner and the aircraft is on a taxi way I release the brakes by loosening a bleeder on each mlg enough to release the brake. What happens is the brakes were hot when the parking brake was set. The were cold when the tow was started. However, dragging brakes rapidly heat up and expand. Dragging brakes now become locked brakes. Citation multi disc brakes will do the same thing. If the pilot set the parking brake to prevent the aircraft from rolling at idle and no more than that we have the same problem. Those big engines will move the aircraft into position for takeoff however, as the roll begins the brakes very rapidly heat up and soon they are locked. I believe this parking brake was set. The amount of braking is determined by the amount of peddle pressure applied when setting the parking brake. It is just a valve that closes off the fluid to the mlg brake caliper. The only way for that fluid to return is by opening the parking brake valve.

[@kurtbilinski1723]

This exact sort of parking brake is offered in the aftermarket to - of all things - kit car builders. Often times, there is no way to have a proper emergency brake, so the existing calibers do double duty. Just like in the aircraft, the pedal is depressed and then the valve is shut, holding that pressure in the lines and caliper. So in the plane, the pressure is totally dependent upon how hard the pilot presses the pedals when the button is pushed, so the parking brakes can absolutely end up with anything between zero and 100%.

[@bendafyddgillard]

see accident report of "Cessna Citation 560 Ultra, VP-CSN" in 2003 in which the parking brake was inadvertently partially or fully on at touchdown. Pilot subsequently had their company checklists amended to add Parking Brake OFF, before take-off and before landing. " Furthermore, trials conducted by the operator, subsequent to the accident, showed that it was possible to move the aircraft at speed with partial parking brake selected. "

[@alexaltrichter1597]

Why is there a "partial parking brake" selection? The Europeans have noted several accidents with these types of aircraft whereby the parking brake was either not releasing or residual pressure in the system applying the brakes, as Juan suggested. A simple electrical circuit on the wheels should be installed to monitor actual wheel speed vs. ground speed, wheel slippage could then be calculated.

[@user-sm3xq5ob5d]

@@alexaltrichter1597 Or "Anti-Skid-in operation", means it is modulating the brake pressure. I would wish for an automatic release of the parking brake by throttle advance. Either this disengages the brake lever or the throttle cannot be advanced when the lever is not fully released. How many times have I set the parking brake on my car! And only when I got of the gas I notice by the rapid deceleration that the brake was still on. Despite having an indicator light in the panel! 🤢

[@eugeneweaver3199]

It appears to me that this is a design flaw. If Cessna refuses to fix it, it's up to us to get the word out AND when you are a pilot flying these airplanes, take personal responsibility.! Add parking brake check to your checklist yourself! Spread the word to every single pilot you meet flying this type of aircraft! If we work together, we CAN make a difference!

[@RupertReynolds1962]

Disclaimer: experience from auto hydraulics may not apply here, but maybe? There is a condition where a hydraulic master cylinder does not quite return fully, which it needs to do, to open the system to reservoir(=atmospheric) pressure and equalise. Although there is little or no system pressure at the time, the system is closed and any expansion (due to heat in the wheels?) can cause pressure to rise and brakes to drag increasingly with time. In extreme cases, they can lock on. In cars and motorcycle hydraulics, the solutions are 1) make sure the master cylinder piston physically returns *fully*. If the lever is adjusted wrongly, this can't happen reliably. And it's not enough to only check for no system pressure. 2) make sure the control lever is operated fully off each time, with no exceptions.

[@RupertReynolds1962]

Apologies. I was interrupted by family and missed an important part. The parking brake valve takes the place of 'master' in what I said above. ideo mkes it clear that a sticking valve, or pilot leaving it set with the brakes only partly on, could cause this problem. I'd be hoping for a change of procedure AND a warning of brake pressure while engine revs are up enough for takeoff.

[@louisboshoff9142]

I was taught how to do a acceleration check speed@distance in the first few take- offs fir my PPL training. And it was reinforced regularly becoming instinctive after that. I get goosebumps that commercial charter pilots flying jets could somehow not have that as pert of their essential awareness regimin on take-off. I was trained in South Africa, only PPL single engine. Thanks Juan for all your fantastic videos.

[@ewthmatth]

Question from a non-pilot: How do you measure distance during take off?

[@louisboshoff9142]

@Matthew H If it is a regular use airfield you know where you should have at least a certain speed depending on the aircraft you are flying. Otherwise time is a measurement. If you are experienced, and with lighter singles you can immediately within a few seconds feel if acceleration is normal or not. It is much more procedural with commercial flying and the airlines. But the basics are the same.

[@telquad1953]

Grateful for the clear explanation of the issues here. Retired after 45 years in navigation aids, radar, and comms in support of civil aviation. As Scott Manley says 'Fly Safe!'.

[@johnnyrocco]

Videos like this makes aviation safer for all. It takes time to pull all the information together, then make the video. You can't expect someone to do this week after week, while also working his regular job, for nothing, do you??? I'm glad we have something like youtube where we can get this great information all for free while the guy doing the work gets paid also. It's a win win for all.

[@steveholton4130]

But he is no where near being renumerated commensurate with the great value, in terms of human lives, prosectively saved.

[@Coops777]

Patrion goes some way towards it. Juan was my first one

[@awuma]

For this type of video, Juan gets no remuneration from KZbin because KZbin considers it "sad" or something like that. He depends on Patreon for his accident reporting videos. Utterly stupid Google policy given that air safety is almost entirely based on the analysis of accidents and the lessons learned, and also increasing public confidence in aviation. Why can millions be made by the Canadian and other corporate producers of the "Air Accident Investigation" shows on cable TV but private individuals such as Juan cannot on KZbin ?

[@hankcalder422]

I just turned 47, and have started flight school. And really watching Juan has taught me a lot. Not replacing my instructor, but in teaching me this. The checklist is so Damn important, being aware of things you may not see in the checklist is just as important

[@frankhuber9912]

@blancolirio you're missing a critical point: the parking brake valve only traps the pressure applied when it is set. It's entirely possible to depress the brake only very lightly when setting the parking brake. The drag may not be immediately evident to the pilot on the next taxi to the runway but it would be more than enough to heat up the carbon brakes on the takeoff roll.

[@samblue5741]

Correct. It is also likely that if you're just using the P brake to stop it from rolling to grab a clearance or something you would not push hard on the brakes before trapping pressure with the P Brake, just enough to stop idle thrust from rolling it. Also, carbon brakes get better with heat which increases the problem on ground roll. Lastly, at fwd CG limits It feels to me that there is not a lot of "extra" elevator authority to rotate around Vr speeds, I don't feel like it would take much brake drag to cause "no rotation". Cessna should add something to trigger the "NO TAKEOFF" light if there is any trapped pressure in the system.

[@tomlawrence713]

I flew Cessna 400 series, CE500 series and Citation CJ series aircraft. Parking brake controls appeared the same on all aircraft. My procedure on releasing parking brake was to pump the brakes after the parking handle was released to verify the parking brake was released . LR45 has parking brake warning on takeoff configuration ICAS. Bombardier certified that aircraft the same FAR25 certification requirements that the B777 met. Europeans were smart requiring this configuration warning for this. Cessna will stick by there present checklists to evade a lawsuit. Excellent video

[@KennethAGrimm]

I hope the NTSB has enough brains to recommend this change not only in its final recommendations to Cessna but also to the FAA to "require" this, thus giving Cessna a legal "out" to make the change "...only because the FAA unnecessarily required it...". Future safety is more important than Cessna paying for their negligence, much as they ought to.

[@thisisnotmax]

Is it possible for the anti-skid system to vary the hydraulic brake pressure felt at the brakes with the parking brake engaged? Or would the parking brake valve, when engaged, prevent the anti-skid system from varying the hydraulic pressure going to the brakes?

[@user-sm3xq5ob5d]

@@thisisnotmax From the schematics I take it that the parking brake lever simply applies any pressure that is in the system to the brakes. Upstream in the brake line is the ant-skid-controller which modulates the pressure. From the picture of the skid marks it becomes clear, as Juan mentioned, that the wheels were skidding more and then less again. The stripe was not continuously the same strength.

[@3wireflyboy1]

Bummer all around Juan. Great video, keep it up. Thanks!

[@peterstickney7608]

Some quick thoughts - If the parking brake isn't fully released - the system partially pressurized, then the wheels will roll, with some drag, until some of the weight on the wheels is relieved as the wing starts to lift - at which point, the wheels would lock, as the friction of the brakes exceeds that of the wheels on the runway. At that point, the antiskid would detect the lockup and relieve the pressure, then the brakes would lock again as the antiskid cycles. Other thought - since the parking brake valve is holding the pressure released into the system by activating the toe brakes, if the toe brakes are only partially applied, then it's possible to have a partial application of the brake that isn't enough to stop the airplane, but will hold it back. From teh system diagram, the parking brake valves are check valves - one-way valves - they'll hold the brake pressure at a certain level, but will permit additional pressure to be added by normal brake application, but not released.

[@notheisenbear5686]

Almost, but antiskid is before the parking brake system and can't effect pressures after it. (It just locks the pressure in after it). The skid marks are likely from suspension hop as the tires lose grip.

[@leokimvideo]

Humans are amazing at finding a way to make a aircraft system work against them. If there is something that can be done wrong, it's only a matter of time before it's found. The FAA's job is to act as quickly as possible to avoid this from happening over and over by acting a tad faster in reporting the incidents

[@amirnovini8386]

I owned and flew a C560 or Citation V for several years. A couple of notes; I don’t recall the parking brakes ability to hold back two P&W JT-15 Ds with almost 6000 Lbs of total thrust! So our procedure was to release the parking brake on taxi, check brakes for rolling and stopping while taxing on both sides (left and right) and never touch parking brake handle again. I ‘believe’ a partial engagement is possible and the activation of anti-skid is also possible with brakes heating and locking while aircraft is rolling and the system would not know of a ‘partial engagement’……

[@LonSeidman]

Great analysis Juan.

[@christianpetersen1782]

Thanks Juan, it’s so good to have your amazing in depth expertise on YT. 👏

[@georgobergfell]

Excellent report, as always, Juan. Ididn't know, stuff like this could even happen...

[@donalddodson7365]

Great update. I really appreciate your perspective clearly underscoring the "takeaway" lessons from your reports on mishaps. No histrionics, no sensationalism, and value added from your professional pilot experiences. (You reminded me of a hydraulic parking break valve I had added to one of my POV trucks. I believe the lever did not release the brake fluid pressure unless there was pressure from the foot pedal, too.)

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!💕

[@JasonFlorida]

Its refreshing to have the experience and expertise of a great pilot analyzing these incidents with the purpose of keeping US safe so we don't screw up and make the same mistakes. Great job Mr. Juan Brown! Very much appreciated!

[@tomthumb1322]

Been watching Ryan at Missionary Bush Pilot for a while and he always picks his spot for "air speed alive" before advancing the throttle. If I was a pilot, I would add the p brake to my checklist if it wasn't already there. Never take anything for granted.

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!💕

[@markb.1259]

As usual... your breakdowns of these aviation accidents is exceptional! Thanks Juan!

[@tripg4624]

Was waiting for your analysis Juan. Great job as usual!

[@bobroberts2371]

While I don't have aircraft experience, I have extensive automotive and industrial experience. The diagram is more of a theory of operation rather than exact schematic however there is enough detail to sus out operation. Working the system from top down. Dotted black lines are electrical connections Purple lines are hydraulic system returns ( from the basic diagram it appears that when the toe brakes are depressed, this bleeds pressure from the control side of the Power Brake Valve. The output of the PBV is what applies the brakes. This is a fail safe, if a toe brake valve leaks the brakes apply rather than not being operational. ) Green lines are returns to the supply reservoir . Red lines are what applies the brake calipers. Blue lines are the emergency braking system. Working the system from bottom up Shuttle valves at wheels. This selects between the service braking system and the emergency braking system. This is basally 2 check valves per wheel that automatically select between the two. If the emergency braking system is applied, the rest of the system has no effect, the brakes remain applied. Parking brake check valves. When the parking brake lever is in the OFF position, fluid can flow in both directions. When the parking brake lever is in the ON position, fluid can flow to the wheel brakes through the check valve but not away from the wheel brakes. This means that the pilot can move the parking brake lever to ON then push the foot pedals in order to set the parking brake. If the parking brake lever is set to ON and no other action taken, the aircraft will still be free to roll. Anti skid servo valve. This is what bleeds pressure from the red lines in order to release the brake caliper preventing the wheel from skidding. From the diagram, it DOES NOT have the capability to apply the brakes. Power brake valve This directs hydraulic pressure to the rest of the system when the toe brake pedals are depressed. The system is set up so a pressure reduction in the purple lines causes the valve to move allowing pressure to flow from the accumulator to the rest of the braking system. Accumulator / hydraulic pump This is where the system gets operational pressure. This system acts more like air brakes on a large truck than hydraulic brakes on a car. Toe brake pedals This bleeds pressure from the Power brake valve to the reservoir to allow the service brakes to apply. Weight on wheels switch ( not shown ) Juan replied that this arms the anti skid system when the aircraft is on the ground.

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!!💕

[@bobroberts2371]

Part 2 So, if the parking brake lever is in the ON position, the brakes can be applied through the service brake system but the brakes will not release. This means that the anti skid system has no effect in reducing braking pressure. The light / dark skid marks may be from the brakes overheating and developing uneven braking forces as the brake rotor warps. Another possibility is the runway has differing friction coefficients / surface texture causing the skid to change. If the skid marks were from the anti skid system and the pilot was using the toe brakes, I wonder if he was trying to stop but forgot to cut engine power If a toe brake valve developed a leak, the brake for that side would apply. Left and right would have to leak at the same time in order for both brakes to apply so I don't think that this is the case. If the Power Brake Valve developed an internal leak on the purple line control side, this would apply the brakes and allow the anti skid to operate. The real question is, for this particular PBV component, is there an overlap between L and R systems?

[@michaelsteven1090]

@@amytaylor8910 Why do you have a mask on in your avatar?..Were you in very large group of people, who were breathing?

[@RGB06084]

Great report Juan! Thank you!

[@kevinferrell6466]

Excellent review. You and Mentour pilot are KZbin's best accident reviewers. And your presentations, already top-shelf, are improving with each (unfortunate) review. Thanks.

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!!💕

[@kevinferrell6466]

@@amytaylor8910 Hello, Amy. Are you friends with the &&& pilot, Juan Brown? (blancolirio) Hope you are smiling.

[@amytaylor8910]

@@kevinferrell6466 hey. No I’m not. Yeah I always try to smile. Where are you from?

[@kevinferrell6466]

@@amytaylor8910 Clearwater florida. And you?

[@amytaylor8910]

@@kevinferrell6466nice place. I’m originally from New York but I live in VA. How’s the weather there?

[@tdimentional2048]

Great job Juan. Great analysis that should help save lives.

[@williamcandee5267]

Great video, Juan! You explain what had troubled me about this accident: IF the pilots had for some reason aborted the takeoff after V1, which everybody was assuming was the reason for the tire marks on the runway, WHY did the witnesses seem to indicate that the engines were at full takeoff power throughout the accident sequence ("normal" sounding to a witness beyond the runway end until the one engine evidently ingested something from the power pole), and why did they fly for a distance? That's not the typical abort-after-V1 profile. We assumed it had to do with the elevated runway, perhaps, but it didn't feel right. This sort of explains it. And the report indicates, as you note, that indeed the engines were at takeoff thrust throughout the sequence. The one witness's observation about not seeing the nose wheel off the ground at the intersection, and the observation that the a/c was moving slower than usual, suggest that some level of braking was being applied very early in the takeoff roll, retarding the acceleration and holding the nose down. And yet the skid marks and antiskid "chirps" don't appear until well down the runway. How was it that the tires were rotating on this aircraft at all with the parking brake on, and if takeoff thrust was enough to overcome the parking brake, why didn't we see skid marks until they're 2/3 down the runway? Was MORE brake pressure applied by the system later in the roll? How does that make sense? One possibility is that the lift component from the higher speed as the accelerating aircraft got towards the end of the runway would make the aircraft lighter on the tires, reducing friction between the rear tires and the ground so that the ground wouldn't turn the wheels and instead they would skid. (Indeed, maybe that's the explanation.) If so, that supports the idea that the parking brake was applied from the very beginning and indeed takeoff thrust in this thing is enough to overcome the parking brake (as it is in my automobile). If that's the case, then Cessna indisputably needed to have the parking brake as part of the NO TAKEOFF warning system. With the brake on, and takeoff power applied, the aircraft behaved normally-ENOUGH that the pilots didn't immediately decide to abort. What is truly-disgraceful here, and I know you're too polite to say it, is that some European agencies (or smart customers) apparently required that the parking brake be part of the NO TAKEOFF warning system, so Cessna plainly has the wiring and computer logic already in place to provide this safety measure but decided not to include or activate it in US-registered aircraft. This also reminds me a bit of the Ameristar Charters MD80 accident, where the Captain (who had a zillion hours in DC9-series aircraft) pulled back on the yoke, got nothing, pulled further, still got nothing, and immediately aborted even though he was beyond V1, basically saving everybody. NTSB said that had he taken even a couple of seconds to think about it before aborting, everyone would have died, as they would if he had tried to take it into the air, because it was under no circumstances going to fly. Being present and fully-focused in every moment of the takeoff is what allowed him to react decisively to an anomaly, whereas these poor guys evidently didn't have that edge-of-their-chairs, looking for reasons not to depart, knife-edge awareness that would have allowed them to timely abort. I like the guy who says that every landing is an aborted go-around. Perhaps there's a component of that mentality that would have saved lives here.

[@axelknutt5065]

@William Candee referring to the first part of your post about the skid marks, maybe the tyres were rotating initially (assuming the parking brake was ‘partially’ set) but wore a flat spot. The flat spot might only grab slightly for a start but it would grow to the point where it’s just going to lock into that position on the tarmac and leave a continuous skid mark. This might even explain the intermittent darker patches which have been attributed to the ABS.

[@jasonross3294]

XLS serial number 6001 and up wiring diagrams show a proximity switch at the parking brake valve lever that is supposed to trigger the no take off warning annunicator. N560AR was SN 6026.

[@davidd6635]

Thanks, this helps clarify one of my questions if there was a speed warning / no take off condition annunciator on this complex bird.

[@blancolirio]

hmmmm interesting. Euro models only?

[@jasonross3294]

@@blancolirio The wiring diagram doesn't specify European certified aircraft, the print is applicable for aircraft serial number 6001 and up. The IPC lists the park brake proximity switch being effective on earlier serial numbers that were British, Denmark, and French certified aircraft.

[@oreo10111]

@@jasonross3294 USA Certified aircraft do not have the proximity switch regardless of aircraft age or serial number, the wiring is not present in the aircraft I am familiar with that is SN6100+

[@oreo10111]

@@blancolirio USA Certified aircraft do not have the proximity switch regardless of aircraft age or serial number, the wiring is not present in the aircraft I am familiar with that is SN6100+ The X+, Sovereign +, Latitude, and Longitude all have a No Takeoff CAS Message through the G5000 System for parking brake on, that is incorporated into the throttle system. I do not believe the CJ3+ or M2 with G3000 have a CAS for P Brake on

[@johnblecker4206]

Thank you for your fast updates on all these plane crashes.

[@Tboneskier]

Juan, tomorrow I will study and understand “Minimum Acceleration Check Speed” for my Saratoga Turbo. It won’t move with the parking brake set but it will move with it half set, ask me how I know. I’ll figure this out and make it part of my takeoff check, like oil pressure, manifold pressure, airspeed alive. I participate in the Wings program every year and I’ll talk to my instructor about it. I’ll even check with our wings region person to see if this is covered. Thanks Juan!!!

[@KennethAGrimm]

"ask me how I know" - We don't need to ask, lol. Thanks for the report; it may go a long way toward safety in the future.

[@steveturner3999]

I wish everyone connected with aviation was as dedicated with regards to finding out cause & effect and making sure it doesn’t get repeated causing loss of life & airframes. Thanks Juan for all you do to help keep aviation safe.

[@coolhand-pictures]

Many thanks for this highly interesting analysis! As always a great video from an absolute aviation expert! Always happy landings from Bonn / Germany.

[@elzarcho]

Thank you, Juan. I'm just a VERY casual simmer, but everything felt wrong about this one. I went and flew a short runway in MSFS 2020 in a Citation, and it definitely goes by quickly. In the sim, the parking brake is just on or off (as far as I know; maybe it can be configured) so the problem wouldn't have ever occurred to me. It's very sad that something like this cost lives. I hope Cessna makes those changes.

[@elizabethannferrario7113]

Thank you from your explicit information, your explanation has been great thank you , this is why i love to listen to you , being a novice .

[@jamesford3648]

As a Fixed wing man MANY MANY MANY Moons for Uncle Sam, you are IMHO Thee BEST for attention to detail and and there is NO 1 Else I watch. As the old saying goes “Take offs are Optional but landings are Mandatory”. Great Job as always.

[@sorenweisshartmann]

Nice to see that you follow up accidents and not only go for.the news as everybody else do. Thanks

[@CraigArndt]

Juan, there is a reference I saw on the checklist for Brakes on the static roll and rolling take off to release, but nothing on parking brakes. I'm not a pilot, but you'd imagine there had to have been a lack of performance immediately if they were dragging brakes. Great job on this, fascinating and sad we have to lose people in order to update checklists, flight control systems... excellent video.

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!!💕

[@maxium4x4]

As usual Juan, you ask and bring forth questions that need to be answered.

[@walterthorne4819]

Juan, excellent ….much appreciated

[@NicolaW72]

Thank you very much for the update!

[@flyingindependence409]

In the MQ-9 Reaper, we had an acceleration time check. It's not what I'd consider a high performance aircraft, but it's flown like an 11k pound turboprop. We calculate TOLD data, including V-Speeds, and time to 50kts. When I takeoff, I call the seconds on the clock in the HUD. "FULL POWER, 12 ON THE CLOCK." If our acceleration time check is 17 seconds, both crew members know to look for 29 seconds on the clock. The Sensor Operator acts much like a copilot, and monitors the speed check. Usually it sounds like "50, SPEED CHECKS," and I'll look at the clock and speed as well, and call "GO." It's a good and critical practice. We have different criteria than standard V1/V2 etc, since it's a single engine aircraft, but it's proven to be a good, safe procedure.

[@blancolirio]

Excellent!

[@MattH-wg7ou]

This is not a shot fired at you, just an observation. But I never realized how often the Air Force crashes drones until I went to AMIC ("safety school"). And how frequently they go lost link. There are a lot of unique challenges to flying drones.

[@MajorCaliber]

Proper (and easy to remember) Physics is always a good thing in aviation!

[@blackhawks81H]

@@MattH-wg7ou I knew a couple guys in the air force who were stationed in Korea as maintence crew on the Global Hawk... One of them swore up and down it was a manned aircraft, and he WASN'T joking..... Scared the shit out of me. Lol Unless DARPA is up to some really crazy shit, and he was saying things he really shouldn't have been saying... I'm pretty sure someone is stupid in this situation, and it isn't me. The hell kind of maintenance was he doing? Haha that was over 10 years ago and I still laugh about it to this day. I really hope some senior enlisted was playing a prank on him and had him convinced like, a pilot climbed in there when nobody was looking and you couldn't see him, cause no windows..because otherwise. Man... I don't know what to say.

[@pietervaness3229]

Yet another aviation operational item to remember ... thanks always Juan

[@garyvale8347]

another fantastic explanation for pilots and non-pilots alike of what exactly went wrong, causing this tragic accident by Juan....thank you sir

[@jimheckert5383]

Another great video. Thanks 🇺🇸

[@gazzathomas1423]

Contamination of the park brake shutoff valve could very well leave pressure in the circuit downstream....that's a very good point Juan.

[@jeanlouisnovel1668]

In all my years of flying different type of aircrafts, I always perform and use the BFATS check; Brake (parking brake OFF), Flaps(set for T/O), Airspeeds(Posted, reviewed), Trims(set for T/O) and S for safety ( T/O clearance, seatbelts, etc). Never failed me. And for God sake Cessna please incorporate the parking brake into the take off warning system! Stay safe everyone

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!!💕

[@seanfallon1076]

Went to A&P school with one of the pilots he was always very professional and had been a pilot for some time when we graduated.

[@ChrisCoombes]

Thank you for this balanced and concise assessment.

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!💕

[@turbofanlover]

Thanks yet again for another outstanding vid.

[@persistentwind]

spot on Juan - make the parking brake a part of the master caution system!

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!💕

[@lisanadinebaker5179]

The locals say MAN-ee-oh (think manny-o). MAN-tee-oh also works and that is what you will hear in most of NC. Wonderful little place on Roanoake Island just before the Outer Banks. Have been fortunate enough to visit the Carolina coast many times. I really enjoy your channel Juan, especially the level of detail you go into. Thanks for all the time you put into making these videos for us.

[@roblachman8919]

Great report Juan. My Granddaughter has her PPL and is now doing CPL. My god this flying business is complicated just trying to get airborne. Hate hearing about crashes. May those poor people Rest In Peace. 🙏 🇦🇺

[@richc47us]

Thank You, Juan!

[@jyoung4805]

One possible explanation is that to land on that short runway requires heavy braking. The Citation landing distances are dependent on touching down at the correct speed and with aggressive braking. Not the kind of braking that most pilots carrying passengers apply. Heavy braking heats up the disks and the pads. Then the aircraft sits and the disks and the pads cool down. So with the cooling, the brakes are not effectively on (the pads are not pushing against the disks). Then they take off with the parking lever still pulled, parking brakes on, and as the aircraft accelerates down the runway the pads and disks heat up and all the sudden the brakes are on (pads applying pressure to the disks) and the skid marks start. With the brakes cooled down, the aircraft might taxi normally and the pilots didn't realize that the parking brakes were on.

[@FranksMSFlightSimulator]

I ‘ll be adding both parking brake and rotation/rejected take-off position to my C172 take-off checklist from now on! Thanks Juan. Cheers.

[@fernandopratesi5378]

Man.. so sad to hear about that midair in Chandler.. I was just thinking how nice it was that I hadn’t heard from Juan in awhile.. condolences to the family.

[@sink61]

In the AIRBUS the parking brake was an called audible “BRAKES RELEASED” or “BRAKES PARKED”. Seemed to work fine.

[@normadesmond9659]

It looks like the Chandler, Arizona crashes were flight school crashes, for sure the helicopter which listed both the flight instructor and student as casualties. Your graphics are always exceptional Juan.

[@alclark6124]

Yet another expert dissection of a tragic accident, sir. Much to be learned here.

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!💕

[@ARFFWorld]

Very informative. Like with our ARFF Rescue vehicles, we can not move the vehicle if the parking brake is on. I think they should do that with these type of aircrafts, or have a loud beep in the cab when the parking brake is on so that the pilot will have no way of forgetting. These types of crashes should never happen. Thanks for this review.

[@henryhbk]

I’d add my son (real pilot) and me (guy who pays for pilot) tried this takeoff in x-plane and MSFS. I gotta say on the best day, it’s pretty close to the runway end lights when the citation lifts off (without the parking brake) on that same departure. He managed to get a 737-max and a 767 off with actually a shorter roll. But as you note, there is zero margin for error here. It must be money that they’re based at Robertson field given that Bradley international (with its 9500’ 6/24 runway) is about a minute away by plane

[@hhedaya]

I commented in your initial video on this crash that it was the parking brake on. I personally witnessed a takeoff from the right seat in a citation a few years back where the captain forgot to release the brake after an extended line up and wait. It took almost all of the 8300’ runway to be airborne and we burst a tire on landing. The first thing you think about is the engines are not making power. It wasn’t until after rotation I looked over and pointed out to the captain the parking brake was set and told him not to raise the gear which he did anyway. They have no chance on a short runway like that. There was definitely a distraction to the crew right before taking off leading the captain to forget to release the brake.

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!💕

[@duanequam7709]

You have the ability to explain what few of us would ever understand on our own. Great job. Thanks again

[@cgirl111]

My 2012 Civic will warn me if I go above 5 mph with the parking break on. I'm pretty sure this car costs less than maybe 2 years of required maintenance on a Citation.

[@tstanley01]

LOL...try two months worth of maintenance...

[@leeadams5941]

Excellent as usual Please cover the crashes at Arkenstol as there seems to be zero coverage of the accidents and a heck of a lot of speculation and verbosity concerning the entire contest. It would be nice to see the truth.

[@tombolin7168]

Thank you Juan .

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!💕

[@coreyandnathanielchartier3749]

Great analysis, as usual, and that 50/70 rule is a handy cross-check. Regarding the annunciator system for the PB, every automobile has a red dash light that shows 'BRAKE', and many newer ones have annoying dingers that at least indicate something isn't right to start rolling. Brake temperature warning might have some use in helping identify this problem along with a warning , and since brake pressure is monitored, residual pressure with brakes released would show a condition of fluid trapped in the wheel caliper areas. I've heard in the past of aircraft that actually got off the ground ok with the dragging brakes on fire, then retracted into the wheel wells, and then.......... I've been within 20 feet of a KC-130 tire that blew off a shattered rim during towing, and it has enough force to de-skin a wing.

[@davedavedave52]

Wow Great analysis, Bold recommendations, areas that do need to be addressed

[@dc8bob]

All my career each time I pulled into position or unto the runway for takeoff I performed what I called the suicide check : flaps, stab trim, bugs and brakes and at the beginning of the takeoff roll...slight .and pull on the elevator to see if there is movement.

[@Kevin_747]

Yep, pretty much how I did it as well. Like your handle. I loved flying the DC8.

[@scofab]

Agreed these definitely need a brake/throttle interface that prevents the throttles from being advanced, or an audible TC warning that would sound, if this were attempted during normal flight operations. In this case the brake(s) may not have locked completely until friction heat caused enough expansion to defeat the ABS system. Good report Juan, thanks.

[@Breenild]

Since a long time I'm thinking about a takeoff acceleration warning system. Thru the GPS it should be possible to evaluate the exact position of the aircraft on the runway at any time. So it's easy for the FMS (which has a database of runway lengths of all airports) to calculate the remaining runway in front of the aircraft at any time. When FMS now do calculations with the actual speed and actual acceleration values, it should be possible do determine the estimated takeoff position. And when it is beyond a specific safety margin, the FMS should give a master warning!

[@rln970]

Great video!. I enjoyed your use of Google maps to explore the area around the runway, particularly showing the drop in elevation at the end of the runway and the power pole that was involved\

[@joephysics5469]

I follow the Missionary Bush Pilot channel here on KZbin. He flies a single engine turbine Quest Kodiac to some of the shortest one way air strips on the planet located in Papua New Guinea. Before every takeoff roll he picks a spot on the runway as his abort point if he has not reached a predetermined speed. If you like bush flying check out Justin's channel. He has good video quality and editing, good narration as he puts that aircraft into some of the most remote places.

[@crazylocha2515]

MBP and Josh Flowers of Aviation 101 are the exceptions it seems to have a target spot and speed in props. Only a few jet pilots on YTube that use it. I like Juan's suggested speed calculations in addition. (That show the work up in video that is)

[@davidd6635]

As Always Juan, Excellent info. Thanks. My two cents agrees with you thoughts about the shuttle valve, is there residual pressure after parking brake released and compounded by the ABS pressures. RIP for those souls, and the rest of us to Learn.

[@KennethAGrimm]

One factor that I did not see mentioned in the comments here yesterday, which I only learned about late last night, reading the "Cessna Citation XLS - Power Brake and Anti Skid System", is that the anti-skid system only operates when the speed is above 59 knots.

[@m118lr]

Very good breakdown of the braking systems Juan. What’s “obvious” to some...isn’t (always) obvious to others. Goes with that ‘no-brainer’ saying..

[@ted70281]

I have learned so much from you. Thank you

[@dryan8377]

one of your best-of's Juan!

[@peterebel7899]

I think this is the best.

[@alyssalebeau3661]

This crash happened at my home airport. This citation was my favorite aircraft on-field. Such a gorgeous aircraft, but such a devastating loss.

[@JSFGuy]

This is what I was thinking.... I did delivery on this type model 99-2008 @ Cessna/Wichita. Lots of flights & taxi runs as a mechanic. I never had any forgot moments like this...

[@drthik1]

Non pilot here but love watching these videos, thanks for sharing

[@ptrsrrll]

Juan, MY BLOOD BOILED at 18.20 when you read out loud that Cessna, ALREADY HAVE a 'NO TAKEOFF' park brake on warning system available for this model, but was not installed. picnic

[@andreylovin8496]

So detailed analysis of a case. Very helpful for newcomer pilots. I will triple check brakes…

[@tymatt4555]

Great stuff Juan. As a high time c500,c560xl, c650 (all same brake) guy I can tell you the brake almost hits your right knee when pulled. The parking Brake pressure is directly related to the pressure applied to the pedals BEFORE the parking brake is pulled! There is NO accumulator. It is very common for a citation to go rolling off a sloped ramp if the chocks are pulled. Because not much pressure was applied to the toe brakes. I personally have had an airplane change parking spots with a co-pilot sitting in the airplane un aware he had moved 60ft down the ramp. I can’t imagine how someone can take off with the brake on(SMH). But I really looks like that’s what they did. Damn shame. Also I always use a parking brake! If my head goes down to do anything to the fms, to brief a chart, or take my eyes away from outside the airplane the parking brake is set. The last thing you need is to accidentally move! I’ve been in several airplanes that the pilot flying released enough pressure to let the airplane roll, with both heads in the cockpit. This always results in a panic stop and one of the pilots saying an f word!

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!!💕

[@speedlever]

Iirc, the brake lever near the pilots right knee in the C650 is the emergency brake, not the parking brake handle. The parking brake handle is behind the center console and is pulled up to engage and pushed down to disengage. That’s from memory which is years old though. I do have a pic of the 650 cockpit and the emergency brake handle by the pilot’s right knee is just to the left of the emergency gear extension handle.

[@tymatt4555]

@@speedlever I had forgot that. Been awhile out of the 650. I do remember that control lock down in the center that we used. Thanks for the correction. I went form the 650 to the 560xls, sure I still have a little of mix in my head. Strange mix of everything in the xl.

[@speedlever]

@@tymatt4555 No worries. Been years out of the cockpit for me. Flew a bunch of different Citations but never had the pleasure of the 560xl. I loved the 650 (III and VII). I hate to think all I’ve forgotten.

[@tymatt4555]

@@speedlever the 7 was a great flying airplane. The xl not so much, heavy on the controls and main gear way to far aft of CG. But it’s a hauling truck, with good field performance on that straight wing. And lots of baggage space. I’m in the falcon 2000lx now and it flys almost as nice as the 650. But lots more power and range.

[@flyguy68]

SB is needed to add the brake config to the take off config parameters like in the challenger 604. With the brakes set and throttles forward you get a T/o config brakes.

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!!💕

[@ronaldjennings8057]

It was probably good video my friend have a great day God bless🙏🛩

[@DaFlyingFox]

Yes, we had a similar occurrence on a Citation XL about 15 years ago. During takeoff the aircraft would not rotate, crew aborted and stopped safely. I do not remember whether the parking brake had been set accidentally or whether the brakes locked up partially due to a defect. In any case, those XLs will not rotate in such a situation, period. On the current type that I fly we do have an "acceleration indication" (g-force) on our PDU (primary display units) and during takeoff there's an official callout "acceleration checked" at about 50 knots. Potentially a life-saver!

[@peterebel7899]

Very good questions at the end of this vid.

[@bizjetfixr8352]

The parking brake valve traps whatever pressure is applied to the brakes when the parking brake is set. Best procedure is to stand on the brakes (with power/28v on) to energize the power brake pump, stand on the brakes, then set the parking brake. Newer airplanes have done away with master cylinders on the rudder pedals entirely, pedals just apply inputs to the brake metering valves downstream from the electric brake pump. Any other procedure just traps whatever residual pressure happens to be in the system. Sometimes its enough to keep the airplane from rolling, especially with new/good brakes on a level ramp Worn brakes? Sloped ramp? Maybe, maybe not. Another issue was related during a line shack BS session about this. C560 was chocked, needed to be relocated to other side of field. Guys hook up, start towing it across. Had to stop before crossing the active. Start to pull again, wont move. Brakes are locked. Parking brake set in cockpit, aircraft door locked. Pilot had to be called out to unlock door and release the brakes. The consensus was that the pressure gradually increased as the dragging brakes temp increased, thus locking the brakes when stopped Same system has been used in the 500 series since day one, along with the 650s. One might ask why there is suddenly a problem. The 560XL/EXCEL has an abundance of power, compared to the earlier 500 series. When mechanics do ground runs, especially when you need to run it above 85% and are light on fuel, its good practice is to stand on the brakes, apply the parking brake AND chock the main wheels. Its easy for the airplane to overpower whatever drag coefficient there is between tires and pavement. So why does this problem occur recently, when the parking brake system has worked fine for the previous 40-50 years? I'm just guessing, but one of the factors may be that there are a bunch of pilots out there who dont know, or care to understand, how their airplane's systems actually work. You will debrief these guys who write squawk scenarios that "cant happen", then get the "deer in the headlights" look when you start asking for more details. Any mechanic/AMT who has spent any time at all debriefing flight crews can tell you this.

[@gretchenmalara3029]

Good job Juan. Forgot to mention that the crew should have Aborted with a loss of directional contol prior to V1, which is part of the standard takeoff breifing. A Monday morining QB would have used wet runway V1 data on this short runway. This would give them more runway available to stop on if a rejection was needed.

[@falconfitty]

Don't know if it has been mentioned. The Dassault Falcon series (at least 50/900) had a G acceleration meter in an upper corner of the PFD. The takeoff numbers included this minimum acceleration number. It is the only series of civil aircraft I have seen with this but I thought it was wonderful. A quick glance at 80 Kts told you if the airplane was performing as advertised. Left you in a relatively low speed regime for a reject if you weren't accelerating properly. Anyhow, Excellent breakdown Juan!

[@Indzeosko]

I am not a Pilot but love aviation. Love your videos.

[@tomheringer2047]

Very professional and thorough presentation Juan! Expect an FAA Airworthiness Directive to be issued in the very near future to address this problem. I see the installation of new parking brake valves on the Excel series of aircraft and then the possible install of a redesigned valve when they become available. In addition, the parking brake position will have to be incorporated into the "No Takeoff Warning System". If this modification is not feasible, then an independent subsystem will have to be designed to trigger the Master Warning System when the throttles are advanced to the takeoff position and the parking brake is in the set/on position. Flight Manual and checklist amendments will have to be included as well. For your information, the larger and more elaborate models of Cessna Citations have the parking brake position monitored by the No Takeoff Warning System. The 560XL series shares it type certification and type design specifications with the original Model 560 and was delivered as such.

[@SteamCrane]

Probably 3 years from now.

[@tomheringer2047]

Less than full brake system pressure can be trapped in the brakes under the following scenario. The brake metering valve, which is controlled via the toe brakes, modulates brake pressure from zero to a little over 1000 psi. What happens is the pilot applies just enough brake to stop and hold the aircraft (which is at idle thrust) then decides to set the parking brake. At this moment, there may only be around 300 to 400 psi trapped in the brakes. Moving the aircraft forward again while forgetting to release the parking brake is easy, just add power and it will roll forward. It will definitely require more power than normal to maintain or achieve a given speed. Bottom line here is when setting the parking brake on a Cessna Citation is to fully depress the toe brakes so the brake metering valve can apply maximum pressure to the brakes.

[@vidznstuff1]

If the park brake was on, cycling the antiskid should have released the brake. But the Cessna schematic shows the park brake is a check valve, which means the antiskid servo would pump the pressure back up again with the park brake holding the new pressure. That's the part of this design that sucks, IMO. The park brake check valve should not be where it is in 17:21 schematic, but perhaps rather between the power brake valve and antiskid servo valve.

[@oreo10111]

It's a wacky system that has never been brought up by Cessna in detail. The Latitude, Longitude, Sovereign + and X + have No Takeoff warnings with the P Brake on... I'm not aware of any other Citations that do. It could be fixed by adding it to the micro-switch that is already in the throttle quadrant that annunciates No Takeoff if flaps are beyond T/O, speedbrakes deployed, or out of T/O trim... why the P Brake isn't on there is mind boggling.

[@doug1320]

@@oreo10111 I'm surprised that the high-end Cessna jets that you mentioned above don't have parking brake NO TAKEOFF warnings. In the Citation 525 M2, there's both a NO TAKEOFF CAS message on the primary flight display whenever the parking brake is set. And when you advance the throttles for takeoff beyond the cruise detente, the warning becomes an oral warning. Why is it the case that the lower end of the Cessna jet lineup has more sophisticated parking brake warnings? Is it because all of the planes that you mentioned require two pilots a and they should know better working as a team? Or put it another way, catch each other's mistakes? In case some don't know, the Citation 525 series is certified for single pilot operations.

[@Maynardtkrebs]

Great analysis. Put check parking brake on the list yourself, don’t wait for Cessna which will be looking to CYA before changing anything.

[@vinquinn]

If they supply a warning on the European models, it should be applied across the whole line.

[@stevencarter7031]

I have had a citation accelerate with the brakes locked during ground runs..it went about ten metres before I got the power back... I know of another 560 citation went half way down the runway on take off with the wheels locked and on fire..

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!💕

[@colinwallace5286]

There is a handy little item called a Mico-lock, which is a selectable valve that maintains a hydraulic brake application in trucks and cars. If you activate it, it allows you to apply the brakes, but does not release pressure when you let off the pedal. If you inadvertently flip the lever, the next time you apply the brakes, even lightly, they will not release, with some scary consequences. If the park brake on this aircraft is a similar sort of one way valve, it could be that it isn’t completely releasing, even if the park brake is showing that it IS released. Two different accidents with similar circumstances is awfully coincidental.

[@AdabAbu]

Thanks for sharing

[@briggsahoy1]

Very informative, thank you, RB, Nova Scotia, Canada.

[@amytaylor8910]

Hello there👋👋,how are you doing today?hope you’re having a wonderful day?GOD BLESS YOU!!!💕

[@Neil_]

The skid marks starting well down the runway makes sense to me, with heat increasing from the dragging brakes, and loading on the tires decreasing as the airspeed built up.

[@MrDLRu]

Lots of knowledgeable folks called that one when it first happened.