FAA Grounds All Cirrus Vision Jets over Angle of Attack Issues

https://www.flyingmag.com/faa-grounds-cirrus-vision-jets

by pdx_flyer • 7 years ago

57 61 7 years ago

danaliv3• 7 years ago

Here's the directive: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/...

This isn't really a grounding, at least not the way the 737 MAX is grounded. Cirrus jets can't be flown until the AD is complied with, but complying with the AD is a (relatively) simple matter of replacing the angle of attack sensors. Once that's done, the aircraft is airworthy again.

The issue is a "quality escape," i.e. the existing sensors weren't built to spec. There are two screws that attach the vane to the potentiometer; the factory didn't torque the screws properly and didn't apply thread locker to them.

So this is a manufacturing error, not a fundamental problem with the design. I say that just to provide contrast with the MAX issues since the problems are superficially similar, but quite different once you get into the details.

pdx_flyer2• 7 years ago

Exactly. The AD says that the plane can be flown once the part is replaced.

AceyMan• 7 years ago

Another data point to remind everyone how AoA is one of the most important metrics wrt flying an airplane (airspeed is right up there, too).

Obligatory citation; imho, one of the webs's great resources—

https://www.av8n.com/how/htm/aoa.html#sec-aoa-intro

mikeash3• 7 years ago

Airspeed is mostly, although not entirely, important as a proxy for angle of attack.

dsfyu404ed5• 7 years ago

But you don't need a dedicated sensor for it. The artificial horizon does that job too.

Edit: To be more clear, the artificial horizon combined with other sources of information available to the pilot (airspeed, stall indicator) provide the pilot with the same level of situational awareness as knowing his/her AOA outright from a dedicated sensor.

cjbprime2• 7 years ago

everyone how AoA is one of the most important metrics wrt flying an airplane

Pretty difficult argument to make when most planes do not have AoA sensors!

AdrianB13• 7 years ago

I am qualified to fly several types of small planes, none has an AoA. I was able to fly with a faulty Pitot reading (airspeed), but I would not do it often; I had never felt the need for an AoA sensor, not even when I was flying in "unusual attitudes" (intentionally).

dsfyu404ed5• 7 years ago

I used to work as an apprentice for a GA mechanic (never pursued it, went to college instead).

Disassembling something, inspecting it then performing reassembly and properly torquing the screws with locktite per some published procedure is one of those things aircraft mechanics do all day.

Unless the design of the sensor would make it inaccurate after being reassembled (I'm skeptical of this, it wouldn't make sense for a few reasons) this is kind of a dick move to the aircraft owners that they're probably doing in the name of "look how careful we're being"

Any certified mechanic anywhere can do the former with no lead time and if it turns out the threads are close to stripped out from a loose sensor banging around on there then replace the sensor. It doesn't make sense to replace the sensor off the bat unless you just want to be seen "doing something".

toomuchtodo• 7 years ago

It’s probably the right call from an optics perspective so soon after the 737 MAX fiasco.

It’s more expensive than a workbench fix, but cheaper than bad publicity and a loss of faith in FAA governance. It’s a shame the cost is being foisted on GA owners though, owning a private plane is expensive enough already.

spectramax• 7 years ago

Unless the design of the sensor would make it inaccurate after being reassembled (I'm skeptical of this, it wouldn't make sense for a few reasons) this is kind of a dick move to the aircraft owners that they're probably doing in the name of "look how careful we're being"

I think your cynicism is uncalled for. FAA found an issue that is life threatening to pilots and passengers, just because pilot/mechanics are aware about how careful they are with their planes, does not mean that you invalidate the actual manufacturing issue that is found with these AOA sensors.

"We are aware, we are not stupid, don't tell us what to do." - this is a wrong attitude especially from an Aviation mechanic, unless I am missing something, otherwise please elaborate.

peteradio• 7 years ago

Is this the same manufacturer as the sensors on the MAX?

danaliv3• 7 years ago

Good question. I don't think so but I can't tell for sure. They make pitot-static probes for Boeing and Airbus jets but I don't know if their AoA sensors are used in commercial aircraft.

duxup2• 7 years ago

It's really amazing how AA and airspeed are so... difficult for pilots to perceive that they're totally reliant on the sensors to tell them.

Speed I guess makes sense, just amazing how a pilot so easily can slow a plane too much, change the angle too much and have no idea what is up.

bwilliams18• 7 years ago

Angle of Attack doesn't refer to the angle of the plane relative to the horizon but the angle of the plane relative to airflow.

briandear3• 7 years ago

Under VFR what you say is true, under Instrument conditions the AoA indication is critically important. Once you’re in a cloud, you literally can’t tell which way is up without instruments and the AoA is an essential part.

zzless2• 7 years ago

It depends very much on the circumstances. In most slow GA airplanes (and yes, the Vision jet is a slow plane), one can perceive both the airspeed and the angle of attack by the control feel ("mushy" vs "firm"). Many older airplanes (for example the fastest GA piston twin, the Aerostar 601P) did not have even stall indicators. That airplane used to scare the crap out of me during a takeoff on a hot day. Everything had to be done just right ...

You mostly need a stall indicator or an AoA during tricky procedures like really short field operations (which in the Aerostar world translates to "just don't"). Jets are a slightly different story however I do not believe the VJ gets fast enough for that to matter.

AdrianB13• 7 years ago

Most GA pilots are not reliant on sensors, we learn to fly with no instruments. Most airline pilots fly on instruments and almost never without. My instructor told me in the school I will have to learn to know the speed without looking anywhere but feeling it from the way the plane flies. He is right. Flying too much on instruments is taking away the feel of the plane, there are skills you can train and hone and there are skills you loose due to lack of use.

dmitrygr• 7 years ago

They did not ground them. They issued an emergency AD (airworthiness directive). As soon as you comply (replace a sensor) or if you already don't have a faulty sensor (a specific model number was bad) you may fly

holtalanm• 7 years ago

in light of this information -- i think the headline should be changed within HN to 'FAA Issues Airworthiness Directive for Cirrus Vision Jets' or something to that affect.

pdx_flyer2• 7 years ago

I just quoted what the article title was. I didn't write the article.

devy• 7 years ago

For those who are annoyed by flyingmag's un-close-able lightbox hovering the article if you have adblockers installed, here is the content: https://outline.com/3zUyc6

caprese• 7 years ago

Is this exceptional news?

I am curious how often this happens generally

I’ve been told to consider how issues evolve after they stop being reported, and so I am skeptical whether this is exceptional at all because aircraft groundings are only in the public interest because of the recent worldwide coordinated grounding

nzjrs• 7 years ago

I'm also skeptical, if I was Boing I would be surfacing every regular FAA technical directive to the public.

"Its ok everyone is bad like us"

dlgeek• 7 years ago

Not very.

This is pretty much the same as a standard car recall, just with more enforcement teeth. FAA says you can't fly until you replace a part that had a manufacturing defect. Replace it and you're good.

staunch• 7 years ago

Given how absolutely critical sensor data is becoming to aircraft software, it seems like airplanes should probably have a dozen redundant AoA sensors and pitot tubes. And the sensors should be of different design and manufacture, so they're unlikely to all fail under the same conditions.

It seems like the Air France 447 and 737 MAX crashes could have been avoided just by having highly redundant sensors.

This is probably what will have to happen for fully self-flying aircraft, so why not do it now with partially self-flying aircraft?

exabrial• 7 years ago

I was watching a youtube video last weekend of the landing procedures in one of these jets. The cockpit and avionics are very modern. They automate a ton of tasks for the pilot and the displays are more "English" than three letter acronyms.

outworlder2• 7 years ago

Good news is, you can spend some money and upgrade any airplane, even a 1950's Cessna to glass cockpits for a similar experience.

shereadsthenews• 7 years ago

To whom is this of interest? How many HN readers are flying around in a $2m jet, fewer than 100 of which exist.

PaulAnunda• 7 years ago

HN readers who have a general interest in all things aviation.

duxup2• 7 years ago

That is a strange looking jet with the engine on top angled down...

outworlder2• 7 years ago

That's because it only has one engine. The other option would be to place it on its back, but it would make for a longer jet.

It's supposed to be cheap for a jet.

zzless2• 7 years ago

It is absolutely puzzling to me why anybody would prefer this 'jet' to a nice (used maybe) turboprop like a KingAir or an Aerocommander (heck, even an MU2). They are (almost) just as fast (or slow), carry more load and do not require a type rating to fly. Oh, and they cost less and eat about the same amount of fuel too, ... and are less costly to maintain.

Stevvo• 7 years ago

I think they are designed to appeal to SR20/22 owners looking for an upgrade, as the only real advantage they offer on the competition is CAPS (although I'd take the second engine on a kingair over a parachute)

Full glass cockpit is also looks pretty sweet.

ggm• 7 years ago

I'm sorry but I read a string of negative messages about the FAA in this. Firstly, that they know they need to be seen to act more strongly, and secondly they lack courage: they did it to GA not commercial because they're scared of the airline lobby.

Why didn't they act like this to commercial aviation?

FAA Grounds All Cirrus Vision Jets over Angle of Attack Issues

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