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.

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.

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. "

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.

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!'.

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.

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

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’……

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.

@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.

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

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.

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.)

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.

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

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.

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.

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!

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.

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!!!

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

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

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.

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.

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.

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

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

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.

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

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

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.

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.

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

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.

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

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!

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

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. 🙏 🇦🇺

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

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.

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.

Juan , Kenneth Grimm’s comment should be highlighted because he is exactly right. The parking brake in the Excel merely traps the pressure in the brake system that is applied by the brake pedals. A light pressure will stop the aircraft from moving at idle power but not at takeoff power. The carbon brakes become much more effective as they heat up , which is why they locked up 2/3 down the runway. The anti skid system works by comparing wheel speeds and releases brake pressure on a wheel when it slows to 50% speed of the other wheel. If both wheels lock up the anti skid will do nothing. I have been flying Excels for 20 years and only one I have flown had the “no takeoff “ warning on the parking brake and it came from Europe.

Great analysis Juan.

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.

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.

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

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!

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.

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.

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.

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.

From the diagram and your description on how to set the parking brake, I can imagine the following scenario: The pilots brought the plane to a normal stop with normal braking force, then set the parking brake. The set parking brake just kept the pressure the pilots had applied at the time they set the brake. Aircraft didn't move, engines at idle. When they were finished updating the FMS, they advanced the throttle, maybe slightly wondering why they had to apply a somewhat higher thrust to overcome the resistance of stopped wheels. They didn't stop again on the runway but just opened the throttles for the takeoff run, not noticing they were still applying a normal braking force. Since they didn't do the takeoff performance check, they thought they were accelerating normally and tried to take off. The result was this crash.

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 .

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.

It would appear that the parking brake would only be applied as firmly as the service brakes were applied while the parking brake knob is pulled out. Could conceivably be applied just enough to not really be noticed, but still enough to interfere with the takeoff... Also, pulling up elevator would drive the braking wheels harder into the ground. A really bad deal.

Juan, nice video, but clearly the parking brake is working as intended. As a mechanical engineer I believe what is happening with the skid marks is that enough lift was generated to allow the tires to skid, the suspension unloaded (moved down), traction re-established, suspension loaded until slip and repeat. Think of tire hop of a car accelerating, just in reverse. The ABS is upstream of the parking brake and can't release parking pressure or reapply parking pressure.

According to the schematic shown, if the parking brake were "set" with only moderate/light pressure on the brake pedals, the lowest part of the system would be holding a partial brake pressure, a drag but not a full hold-back-against-the-engine.

A pilot can make hundreds if not thousands of correct decisions in a career...but it takes only one error or omission....

I follow the Missionary Bush Pilot channel here on KZfaq. 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.

Great report Juan! Thank you!

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.

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.

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.

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

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.

My god-parents died in a crash immediately after take-off in Botswanna in 2011. The day was really hot and the plane was fully loaded when two guys who had something to do with the aviation authority in the region asked to board. Initially the captain said no due to weight but later he changed his mind and let them board the aircraft. They didn't achieve a proper take off and crashed into trees and caught fire. At the time we were told that the engine was fine and the plane was overloaded due to the heat of the day causing the air to be thinner but later the accident was said to have been caused by engine failure. The only 2 people who survived were the aviation people who boarded late. This was a Cessna Grand Caravan I think.

We'll probably never know why they were ignored, but there are two clear indications that something is wrong with the roll. Lack of expected acceleration for the power setting. And when the ABS starts to kick in (because the plane is skidding against the brake retardation at the higher speeds), there would have been a very unpleasant jerking/nodding movement.

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.

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

Juan you mentioned that if you have a second pilot then have him holler at you if you're rolling when writing down a clearance... he really is the one who should be writing the clearance but I get the point that in a single pilot type aircraft, a second pilot may be more of a request or tag along rather than a structured operation. I've been such a second pilot in small charter ops at the start of my career. And yes Cessna should look at this system inclusion in the Config Warning. We had this in the Lear as far as I recall, and every aircraft I've flown since.

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

A dirt cheap computer can determine immediately when a plane isn't accelerating in accordance with thrust settings, weather, load, etc. All planes should have a computer observe nominal performance. A computer can detect much finer malfunctions than a person can.

Thank you for this balanced and concise assessment.

I have more experience on the bombardier jets, but a Lear 31,45 and 60 WILL NOT hold the brakes if you apply full power. Your going for a ride unless your using big chalks.

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..

When I set the parking brake on my car, I ALWAYS jam them on as hard as possible. I don't want there to be any doubt when I try to drive off that the parking brake is on or not. I nearly burned out the brakes on my wife's car one time because I didn't know that she had set the parking brakes on weakly, and the car drove almost normally. Luckily, I detected the problem in time. Dunno know if this is how aircraft parkng brakes work or not, but it's good advice for us folks who only drive non-flying vehicles.

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

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

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!

I still find it hard to believe that operating out of this airport with a jet was a good idea. Many flight schools don’t allow C-172S to operate out of anything less than 3000 feet. Good job JB

Great video. I did alot of single pilot flying in my career. I agree to not setting the parking brake after taxiing begins with some exceptions. When i was single pilot and got a line up and wait i would stop at an angle so i could see the final over my shoulder. Departing from a high speed taxiway at a busy airport would present a problem so when i pulled onto the runway i turned a little to see the final. Controllers are awsome but human,

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...

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

Cessna will be hesitant to mention anything unless the NTSB does more than just mention the position of the Parking Brake in a report. It will have to directly attribute the cause related to Parking brakes or if Cessna changes anything it is an admission of liability.

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.

Thanks, Juan. Love you and Dan. As a non-pilot, I can see why many people should not be involved in an A/F type activity.

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

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!

Takeoff, reject, reject, reject in a T38 at 70 or 80 knots. WOW!

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.

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

It’s one of those stupid human errors. Yes, the pilots should have known to release the parking brake, but it’s a no brainer that it should be a before taxi checklist item. And I seriously question why the parking brake position wasn’t included in the NO TAKEOFF warning system. I think Cessna bears some responsibility here. I’ve not heard about the 50/70 rule before. Excellent practice to follow for any aircraft. There is a tendency for many pilots, especially part 91, to simply wait for rotate speed. On a short runway, that can put you in a place where you can no longer reject the takeoff.

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

one of your best-of's Juan!

And there was little or no room for error on that runway.

Not saying it happened here Juan, but I’ve seen on some automotive brake hoses where they deteriorate inside and form a sort of check valve and not let pressurized fluid back thru quickly when the pedal is released. This usually shows itself as a caliper that won’t apply or one that drags and wears out that pad prematurely.

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

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

The parking brake on these aircraft use a valve that traps fluid/pressure in the line and at the wheels. There's check valves that allow pressure to be INCREASED by pressing the pedals while the parking brake is set but doesn't allow fluid to return the other direction. There's a few ways you can get "partial" braking with this system. One is if you are not pressing the toe brakes hard when you activate the parking brake since whatever pressure is at the wheel is what is maintained. Second is if you set the parking brake when the brakes are hot as they cool the hydraulic fluid contracts and releases the brake pressure at the wheels. It only takes a VERY slight contraction of the fluid to cause a SIGNIFICANT drop in the trapped brake pressure.

If he checked the speed at 10 seconds and had a reject speed, he probably would have saved himself. It adds load to do that, the plane knows the speed and time since it passed maybe 5mph at takeoff power, the plane could flag a rejection warning if you missed 2 seconds, 5 seconds, 10 second speed checks by a statistically significant amount, with 70% more time to reach 100 he probably missed the 10 second speed check by over 30%.