18 Injured CX880 after RTO.
Join Date: Apr 2016
Location: Honky
Posts: 192
Likes: 0
Received 0 Likes
on
0 Posts
Not at all, again can’t speak for the 777 procedures, but for the Airbus the memory item for unreliable speed is only executed if the safe conduct of flight is impacted….meaning for a single IAS fault on takeoff, the aircraft is flown using the remaining valid IAS and the issue is usually sorted by some simple ADR switching once airborne. Enjoy your evening mate
Join Date: Mar 2000
Location: the land of chocolate
Posts: 442
Likes: 0
Received 0 Likes
on
0 Posts
Once you have an unreliable airspeed on takeoff, you have no idea what you're going to get while you are getting airborne and the difficulty you will have managing the aircraft.
Overspeed warnings, stall warnings, perhaps a fun altitude discrepancy while you're at it? Maybe the extension wont play nice? Maybe it's all easy in an airbus, which I doubt..
One of the ex 49ers had a unreliable airspeed on departure, made it in alive and promptly took time off to mentally recover from the ordeal.
A rejected takeoff SHOULD never result in an evacuation, it did in this case, possibly due to lack of communication or just a crazy ISM or both.
It's never like in the sim.
Overspeed warnings, stall warnings, perhaps a fun altitude discrepancy while you're at it? Maybe the extension wont play nice? Maybe it's all easy in an airbus, which I doubt..
One of the ex 49ers had a unreliable airspeed on departure, made it in alive and promptly took time off to mentally recover from the ordeal.
A rejected takeoff SHOULD never result in an evacuation, it did in this case, possibly due to lack of communication or just a crazy ISM or both.
It's never like in the sim.
So hypothetically speaking, taking off on a short wet runway with no stop margin, wind variable, from a ****-hole non-grooved runway, the PM calls 100KTS but you look and see you have 120KT, a quick glance at the standby/ISIS and it too reads 120, the GS reads 120ish and V1 is fast approaching…you gonna stop? This is why Airbus inhibits the above ECAMs after 80 knots as outlined in my previous post.
Join Date: Apr 2016
Location: Honky
Posts: 192
Likes: 0
Received 0 Likes
on
0 Posts
So hypothetically speaking, taking off on a short wet runway with no stop margin, wind variable, from a ****-hole non-grooved runway, the PM calls 100KTS but you look and see you have 120KT, a quick glance at the standby/ISIS and it too reads 120, the GS reads 120ish and V1 is fast approaching…you gonna stop? This is why Airbus inhibits the above ECAMs after 80 knots as outlined in my previous post.
Yeah but it wasn’t a “short wet runway with no stop margin, wind variable, from a ****-hole non-grooved runway”, it was HKG which is our home base. The RTO was done successfully so there’s not much to argue there.
As you said, Airbus inhibits those alerts after 80kts so it’s something that’s seen. You’d have to safely diagnose it between 100kts and rotate. That’s some proper top gun stuff if it wasn’t absolutely obvious.
If you take off, are you going to continue all the way LA if you can’t solve it?
There’s been several stories of crew continuing after seeing unreliable speed before V1 and they’ve nearly ended up in disaster. Don’t remember any of the analysis of those saying a thing about it being a good decision because of possible injuries from an evacuation.
So maybe in this case it was warranted, maybe not, like I said no one can say what the best decision was until all the facts are published. But I’m writing due to your statement which is what urked me in the first place
this is more like a blanket statement and someone’s technique that probably will achieve a safe outcome most of the time, but I’ve given you an example where it may not be not warranted and may result in a negative outcome, hence it’s not published procedure. I’ve never heard of such technique being taught on the airbus (or the Boeing I’ve flown).
I was always told the 80kt/100kt check was to check the other guy is still alive and to check the speeds are the same. Stop if it’s no to either of those!
Join Date: Apr 2016
Location: Honky
Posts: 192
Likes: 0
Received 0 Likes
on
0 Posts
So maybe in this case it was warranted, maybe not, like I said no one can say what the best decision was until all the facts are published. But I’m writing due to your statement which is what urked me in the first place this is more like a blanket statement and someone’s technique that probably will achieve a safe outcome most of the time, but I’ve given you an example where it may not be not warranted and may result in a negative outcome, hence it’s not published procedure. I’ve never heard of such technique being taught on the airbus (or the Boeing I’ve flown).
What are you checking at the 100kt call?
As PF (and Captain): at the 100KT call by the PM, I look at my PFD for my IAS as per the SOP. This is where the training / published guidance / procedure ends on the Airbus...hence my pre-plan for this event (if my IAS is not at 100 knots) is I will glance to check the IAS on the standby/ISIS and then the GS readout on the ND and make the appropriate decision based on the circumstance at that instant. But in my mind it’s not a blanket reject, nor is it published procedure / guidance to do so.
I’ve given this very scenario some thought when I first moved to the left seat, for the very reason that there is nothing published telling us to reject if there is a discrepancy.
I’ve given this very scenario some thought when I first moved to the left seat, for the very reason that there is nothing published telling us to reject if there is a discrepancy.
Join Date: Apr 2016
Location: Honky
Posts: 192
Likes: 0
Received 0 Likes
on
0 Posts
As PF (and Captain): at the 100KT call by the PM, I look at my PFD for my IAS as per the SOP. This is where the training / published guidance / procedure ends on the Airbus...hence my pre-plan for this event (if my IAS is not at 100 knots) is I will glance to check the IAS on the standby/ISIS and then the GS readout on the ND and make the appropriate decision based on the circumstance at that instant. But in my mind it’s not a blanket reject, nor is it published procedure / guidance to do so.
I’ve given this very scenario some thought when I first moved to the left seat, for the very reason that there is nothing published telling us to reject if there is a discrepancy.
I’ve given this very scenario some thought when I first moved to the left seat, for the very reason that there is nothing published telling us to reject if there is a discrepancy.
You’ll end up faffing around trying to work out which is correct and within a few seconds you can’t stop anymore and you’re committed.
I don’t see it that way. It’s a quick glance to cross-check the 100KT call against another another certified IAS instrument, and then if this is good, a gross error check against an entirely different source. Can be done in about 1-2 seconds…
If the PM is doing his job on the Airbus, all airspeed indications are scanned during the roll even during the low speed regime (a slight reference to this is made in the FCTM) possibly enabling a discrepancy to be identified early and a reject safely made during the low speed regime. As PF and PIC I can’t control if the PM has done this or not, hence the 100 knot call is the last chance I have to know if we have a discrepancy. But now we are in the high speed regime and quickly approaching V1 (in some instances) - hence it’s not written procedure to reject - it’s now a command decision.
My responses to you will end here. I just don’t agree with some non-published (for good reason) techniques made by instructors that are then adopted by trainees as gospel - their technique may not fit your situation / context, and could lead to a negative outcome, especially as no formal risk analysis has been performed and you won’t have any leg to stand on should you need to reference it in a court of law (or the chief pilots office).
If the PM is doing his job on the Airbus, all airspeed indications are scanned during the roll even during the low speed regime (a slight reference to this is made in the FCTM) possibly enabling a discrepancy to be identified early and a reject safely made during the low speed regime. As PF and PIC I can’t control if the PM has done this or not, hence the 100 knot call is the last chance I have to know if we have a discrepancy. But now we are in the high speed regime and quickly approaching V1 (in some instances) - hence it’s not written procedure to reject - it’s now a command decision.
My responses to you will end here. I just don’t agree with some non-published (for good reason) techniques made by instructors that are then adopted by trainees as gospel - their technique may not fit your situation / context, and could lead to a negative outcome, especially as no formal risk analysis has been performed and you won’t have any leg to stand on should you need to reference it in a court of law (or the chief pilots office).
Join Date: Mar 2023
Location: In the middle
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
Once you have an unreliable airspeed on takeoff, you have no idea what you're going to get while you are getting airborne and the difficulty you will have managing the aircraft.
Overspeed warnings, stall warnings, perhaps a fun altitude discrepancy while you're at it? Maybe the extension wont play nice? Maybe it's all easy in an airbus, which I doubt..
One of the ex 49ers had a unreliable airspeed on departure, made it in alive and promptly took time off to mentally recover from the ordeal.
A rejected takeoff SHOULD never result in an evacuation, it did in this case, possibly due to lack of communication or just a crazy ISM or both.
It's never like in the sim.
Overspeed warnings, stall warnings, perhaps a fun altitude discrepancy while you're at it? Maybe the extension wont play nice? Maybe it's all easy in an airbus, which I doubt..
One of the ex 49ers had a unreliable airspeed on departure, made it in alive and promptly took time off to mentally recover from the ordeal.
A rejected takeoff SHOULD never result in an evacuation, it did in this case, possibly due to lack of communication or just a crazy ISM or both.
It's never like in the sim.
Join Date: Mar 2000
Location: the land of chocolate
Posts: 442
Likes: 0
Received 0 Likes
on
0 Posts
This says a lot about what a respectable person you are and I can see how lost in time and space you are... you may want to get your judgment checked, but anyway, feel free to come here and make all those nice comments. ISM door was the only door that remained closed.
I'm just spitballing here, as we don't know what happened, this is a rumour platform after all.
There are crazy Captains, there are crazy ISMs, I'm sure you've flown with many of them.
Join Date: Apr 2009
Location: HKG
Age: 54
Posts: 299
Likes: 0
Received 0 Likes
on
0 Posts
Have you considered that the reason the evacuation never happened in the front, was that the pilots stopped them in time, but were unable to cancel the order in the back?
I'm just spitballing here, as we don't know what happened, this is a rumour platform after all.
There are crazy Captains, there are crazy ISMs, I'm sure you've flown with many of them.
I'm just spitballing here, as we don't know what happened, this is a rumour platform after all.
There are crazy Captains, there are crazy ISMs, I'm sure you've flown with many of them.
Join Date: Mar 2000
Location: the land of chocolate
Posts: 442
Likes: 0
Received 0 Likes
on
0 Posts
Crazy is a hyperbole, but there are these individuals you come across from time to time that seem a bit off in their thinking. Many in the cockpit get weeded out in time, not so sure about the cabin as it is less likely they immediately put lives at stake, I imagine.
Join Date: Jul 2001
Location: Hong Kong
Posts: 287
Likes: 0
Received 0 Likes
on
0 Posts
Airbus most certainly advocates rejecting the takeoff if an airspeed discrepancy is detected at 100kts (or before).
From their publication "Safety First" - "Unreliable airspeed at takeoff" March 2021
Monitoring Of The Airspeed During The Takeoff Roll
Case study 3 shows us the importance of the 100 kt crosscheck, which is requested in the Standard Operating Procedure. It is the last line of defense in preventing a takeoff with an unreliable airspeed indication. The flight crew should be prepared to reject the takeoff at the time of the 100 kt crosscheck if an airspeed discrepancy is observed.
Airbus Safety First article
From their publication "Safety First" - "Unreliable airspeed at takeoff" March 2021
Monitoring Of The Airspeed During The Takeoff Roll
Case study 3 shows us the importance of the 100 kt crosscheck, which is requested in the Standard Operating Procedure. It is the last line of defense in preventing a takeoff with an unreliable airspeed indication. The flight crew should be prepared to reject the takeoff at the time of the 100 kt crosscheck if an airspeed discrepancy is observed.
Airbus Safety First article
Airbus most certainly advocates rejecting the takeoff if an airspeed discrepancy is detected at 100kts (or before).
From their publication "Safety First" - "Unreliable airspeed at takeoff" March 2021
Monitoring Of The Airspeed During The Takeoff Roll
Case study 3 shows us the importance of the 100 kt crosscheck, which is requested in the Standard Operating Procedure. It is the last line of defense in preventing a takeoff with an unreliable airspeed indication. The flight crew should be prepared to reject the takeoff at the time of the 100 kt crosscheck if an airspeed discrepancy is observed.
Airbus Safety First article
From their publication "Safety First" - "Unreliable airspeed at takeoff" March 2021
Monitoring Of The Airspeed During The Takeoff Roll
Case study 3 shows us the importance of the 100 kt crosscheck, which is requested in the Standard Operating Procedure. It is the last line of defense in preventing a takeoff with an unreliable airspeed indication. The flight crew should be prepared to reject the takeoff at the time of the 100 kt crosscheck if an airspeed discrepancy is observed.
Airbus Safety First article
Join Date: Apr 2006
Location: Krug departure, Merlot transition
Posts: 661
Likes: 0
Received 0 Likes
on
0 Posts
Wow. I’m actually learning something from this thread! Great discussion.
Thanks gents, esp Jester (good food for thought, plus mature reactions I didn’t even think were allowed on the prune
) and ex Douglas Driver for the excellent reference.
At the end of the day split-second decision, no-one dead and airplane intact, well done. The Monday morning quarterbacking is inevitable in our profession, even Sully had a hard time justifying his decisions (and I for one would be happy to do half as well as he did in a situation half as difficult as he faced).
Thanks gents, esp Jester (good food for thought, plus mature reactions I didn’t even think were allowed on the prune
) and ex Douglas Driver for the excellent reference.At the end of the day split-second decision, no-one dead and airplane intact, well done. The Monday morning quarterbacking is inevitable in our profession, even Sully had a hard time justifying his decisions (and I for one would be happy to do half as well as he did in a situation half as difficult as he faced).