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My favorite is when people try to control the speed with V/S in a descent.

- Assigned 210 knots, selects V/S -1500
- speed starts running away to 212, 215, 220
- deploys speed brakes
- doesn't do anything
- rumbling
- still going 220

- "You know, if you would just click the V/S knob one or two times it would stop doing that"

- still rumbling

"Or you know, pull an open descent

- "stupid Airbus"

- "sigh"
That's why I do V/S towards the last thousand feet of the descent.
 
I see it virtually every engine start. Is this a no-no? News to me. The engines take long enough to start as is....you wait for the one start to be complete before starting the next? I'm confused.

CEO 320/321 engine starts with the IAE you can start engine 2 as soon as the start valve as closed on the first engine. This happens around 45% N2.

The NEO engines PW1133's run and start a lot hotter. Dual cooling in more of a thermal stabilization of the engine prior to start. When you turn the mode switch to start ignition it powers the fadecs and displaces the cooling times for each engine. Now press the dual cooling switch and select engine 1 on to start it. The computer will motor both engines around 10% N2 for the longest cooling time required. It will then close the ENG2 start valve and open Engine 1's start valve fully and motor it up to the start speed. Now you can taxi on 1 engine or as soon as the start valve is close you can start engine 2.

If one engine says cooling and the other, doesn't you are stuck starting the engines independently and cannot use dual cooling

Dual cooling times depend on:
Engine Temp at Shut down​
Time at gate
Density Altitude​
Current OAT​
Engine Oil Temp​
 
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Only in A.FLOOR

Can’t count the times guys would have spoilers out, yet the power wasn’t at idle. (Especially in managed descent). Grrrrr.

This is much less likely in the 737, when the Autothrottle is in ARM it won’t wake up until -15 kts. So you can have spoilers out with good idle power. In the Bus though, I saw a lot more spoilers out yet the power wasn’t idle. “What you tryin to do?”

Speed mode can be a tricky bitch. “Oh, I’m going too fast, let me pitch up.” Spoilers. “Oh, now I need to add power”
 
Lose Both RA's in the bus isn't fun. 5G could be a hoot.

Plane will go into Direct Law when the gear is extended.

FLIGHT CONTROL PROTECTIONS LOST
RA 1 + 2 NOT AVAILABLE
AUTO CALLOUTS NOT AVAILBLE
CAT 2 NOT AVAILABLE
GPWS NOT AVAILBLE
AP 1 + 2 WILL BE LOST (WHEN LDG Gear IS DOWN ONLY)
TCAS REAC W/S DETECTION NOT AVAILABLE
 
Lose Both RA's in the bus isn't fun. 5G could be a hoot.

Plane will go into Direct Law when the gear is extended.

FLIGHT CONTROL PROTECTIONS LOST
RA 1 + 2 NOT AVAILABLE
AUTO CALLOUTS NOT AVAILBLE
CAT 2 NOT AVAILABLE
GPWS NOT AVAILBLE
AP 1 + 2 WILL BE LOST (WHEN LDG Gear IS DOWN ONLY)
TCAS REAC W/S DETECTION NOT AVAILABLE

I'm wondering if the bigger danger isn't that the RAs would get lost, but that they would give erroneous data. Flying along fat dumb and happy stable at 1000 feet and it goes in to flare mode or something.
 
My favorite is when people try to control the speed with V/S in a descent.

- Assigned 210 knots, selects V/S -1500
- speed starts running away to 212, 215, 220
- deploys speed brakes
- doesn't do anything
- rumbling
- still going 220

- "You know, if you would just click the V/S knob one or two times it would stop doing that"

- still rumbling

"Or you know, pull an open descent

- "stupid Airbus"

- "sigh"

This. All this.

I’ve given my students the “always ask yourself: ‘what do you get? What do you lose?‘ when you’re choosing a flight mode.

”i JuSt ThInK vErTiCaL sPeEd Is SmOoThEr”

“You’re new to the jet, let the bus be a bus and I’ve been able to guess exactly ZERO times what descent/climb mode the pilots are using up front.”
 
Lose Both RA's in the bus isn't fun. 5G could be a hoot.

Plane will go into Direct Law when the gear is extended.

FLIGHT CONTROL PROTECTIONS LOST
RA 1 + 2 NOT AVAILABLE
AUTO CALLOUTS NOT AVAILBLE
CAT 2 NOT AVAILABLE
GPWS NOT AVAILBLE
AP 1 + 2 WILL BE LOST (WHEN LDG Gear IS DOWN ONLY)
TCAS REAC W/S DETECTION NOT AVAILABLE

Eeeeeeeeeeeeeyup. We practiced that in the simulator once and it was straight up Donkey Kong.
 
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This. All this.

I’ve given my students the “always ask yourself: ‘what do you get? What do you lose?‘ when you’re choosing a flight mode.

”i JuSt ThInK vErTiCaL sPeEd Is SmOoThEr”

“You’re new to the jet, let the bus be a bus and I’ve been able to guess exactly ZERO times what descent/climb mode the pilots are using up front.”

Guys in the EMB-175 would do FPA -1.5 and tell me it gives them about 1,000 FPM.

"1,000 FPM in VS gives you exactly 1,000 FPM."

*HEAD EXPLODES*
 
I'm wondering if the bigger danger isn't that the RAs would get lost, but that they would give erroneous data. Flying along fat dumb and happy stable at 1000 feet and it goes in to flare mode or something.
The good news there is that the RA almost certainly won't present an inaccurate value that a human would believe for longer than a few seconds before failing itself.

The height is measured by timing the round trip of a chirped signal reflected off the ground. More than anything, a potential 5G problem would overwhelm the RA's ability to receive the reflected signal. Obviously that's still a problem at 500 feet on a CAT II, but there's not gonna be a Die Hard II scenario where a false-but-believable signal is present. (Aside: even a malicious actor with a ground station would have a relatively brief overflight time to attempt something like that).

Unfortunately, Turkish Airlines 1951 proved that automation isn't as savvy as a human and momentary false data is sufficient to confound its operation. That was a 737NG that got a lot of publicity, but around the same time some RAs on A320s were failing in a similar fashion because water was getting into the antennae, freezing, and caused delamination and (IIRC) caused flare mode to activate higher-up on approach.

Maybe it's a race between airplanes and self-driving cars to see who will have object permanence first.
 
So I don't have an extensive understanding of the architecture, but modern aircraft don't have a flight control computer (or n-redundant central PFCs).

I mean, there are still flight control computers under normal circumstances to do all the normal stuff like envelope protection, load alleviation, redundancy monitoring, etc. But those computer don't talk directly to the flight controls anymore. Instead there are Remote Electronic Units (REUs) distributed all around the aircraft that manage a subset of control surfaces, normally following the instructions from a PFC. The REU interprets what the PFC wants and translates that into an actuator command.

But all the communication traffic among the computers on the aircraft is happening over a hardened ethernet network (at least on segmented VLANs I imagine), so all the computers are able to talk to each other instead of a PFC sitting at the center of a star-shaped network. What this means is that the REUs have the same access to the inputs used by the dedicated PFC. So if, for some reason, the all the PFCs stop working, each REU can know what commands the crew or automation want and operate in a "direct-like" mode. Essentially, parts of a "legacy" PFC have been decentralized.

Edit: "modern" = A220, EMB-545/550, G650, G500/G600, G700. The 777 had a progenitor concept with its ARINC 629 buses and ACEs. Now it appears the 777X will the using common-compute system (CCS) and REUs.
 
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I’ll keep it super simple:

Normal Law: Airspeed protections, overbank protections, sidestick requests roll “rate” and pitch “load”.

Alternate Law: You’re having some flight control computer issues, so you may lose some protections because you’ve lost some redundancies, it’s basically a transitional control state to get you back to Normal Law

Direct Law:
The stick directly commands pitch and roll…. Basically, but there are some caveats.

Here is a “MS Paint and FrontPage is kewl” look at some of the laws: Airbus Flight Control Laws
How can we leave out mechanical backup?!
 
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