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-   -   PIA A320 Crash Karachi (https://www.pprune.org/rumours-news/632693-pia-a320-crash-karachi.html)

buzzer90 26th Apr 2024 12:40

Full disclaimer - not a pilot, just an aviation enthusiast.

Post from CVivid read quite concerning if taken on face value. Not that I'd ever know but I'd hope the people at the front don't make a habit of putting themselves in "risky" situations.

slast 26th Apr 2024 15:35

Incidentally there is something weird about the report’s two sets of images of the simulated external view. The bulk of the image areas look to me to have been slightly “squished” vertically, but within them the PFD and Nav Display seem to have been stretched the other way – see the contrast between them and the ECAM. Unless Airbus these days have moved away from having square displays of course. Although this is a simulation, it does rather call into question the value of these picture in showing the visual discrepancy!
https://cimg1.ibsrv.net/gimg/pprune....3b43d22286.png
Report images vs Airbus original

tdracer 26th Apr 2024 17:34


The Captain’s continuation bias was so extreme that once over the runway, a long way down but still airborne, he selected full reverse thrust, and applied maximum brake pedal inputs as the engines nacelles hit the runway.
Did the T/Rs actually deploy, or did he just command them (I've not read the report)? I know that (from looking at DFDR data), that some pilots will start pulling the T/R piggyback levers before touchdown and holding them against the 'deploy baulk' (which prevents above idle reverse thrust until the reverser is basically deployed) - letting the 'weight-on-wheels' signal inhibit actual deployment until they touch down - was that what this pilot was doing?
BTW, as a designer, this sort of thing drives us crazy - if there is some sort of latent fault in the air/ground inhibit that allows a reverser to deploy while still airborne - you may have a very, very bad day.

slast 26th Apr 2024 17:52

Quick reply, out for dinner - no they didn't. More comment later TDR

Right20deg 26th Apr 2024 20:36


Originally Posted by tdracer (Post 11643735)
Did the T/Rs actually deploy, or did he just command them (I've not read the report)? I know that (from looking at DFDR data), that some pilots will start pulling the T/R piggyback levers before touchdown and holding them against the 'deploy baulk' (which prevents above idle reverse thrust until the reverser is basically deployed) - letting the 'weight-on-wheels' signal inhibit actual deployment until they touch down - was that what this pilot was doing?
BTW, as a designer, this sort of thing drives us crazy - if there is some sort of latent fault in the air/ground inhibit that allows a reverser to deploy while still airborne - you may have a very, very bad day.

See Hawker Siddeley 121 Trident. Reverse selection possible and allowed while airborne.

slast 26th Apr 2024 21:03


Originally Posted by Right20deg (Post 11643789)
See Hawker Siddeley 121 Trident. Reverse selection possible and allowed while airborne.

I have a significant story to tell about this, but not necessaily for this thread. More tomorrow maybe........

tdracer 26th Apr 2024 21:04


Originally Posted by Right20deg (Post 11643789)
See Hawker Siddeley 121 Trident. Reverse selection possible and allowed while airborne.

We're not talking about a Hawker - we're talking an A320. Especially since Lauda, most commercial airliners rather robust logic to prevent in-flight deployment since - with big underslung wing mounted turbofan engines, and in-flight deployment is likely catastrophic. I'm just unsure about the A320 (some use radio altimeter instead of Weight-on-Wheels, which could potentially allow reverse after a wheels-up landing, hence the question).

A320LGW 26th Apr 2024 21:58

vilas

This is the first I've ever heard of this.

Stabilisation height is based on VMC/IMC .. and 500'/1000' AAL respectively.

IFR/VFR is an entirely different topic and relates to the flight plan, got nothing to do with stabilisation height.

slast 26th Apr 2024 22:15

tdracer, don't worry: as per this report:para 1.1.6.13.
"At 09:34:23, crossing 07 ft RA, 200 kts CAS (VFE CONF3 + 15 kts), full Reverse Thrust was selected on both Engines. Thrust remained at IDLE, but Thrust Reversers (TR) remained locked and did not deploy as aircraft was airborne (no ground condition detected by the ECU). ENG REV SET ECAM Alert associated with selection of Reverse Thrust in air was triggered along with a Single Chime Aural Alert and Master Caution Amber light.

If you want to know about how HS121 thrust reversers came close to stopping NASA's Air Safety Reportingf System ever being implemnented, send me a PM.

CVividasku 27th Apr 2024 08:44


Originally Posted by buzzer90 (Post 11643550)
Full disclaimer - not a pilot, just an aviation enthusiast.

Post from CVivid read quite concerning if taken on face value. Not that I'd ever know but I'd hope the people at the front don't make a habit of putting themselves in "risky" situations.

Life is always a balance between risk and performance.
If you don't want any risk, don't do anything. What's the most straightforward way to do flight safety ? Remove flight, you're left with safety.

I am talking about "risks" that remain within the realm of acceptable risks for commercial airline passengers, that is, something still extremely remote.


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