Well, we seem to have a consistency here, sadly. Re 4HP's post, (#424) from AB,
Quote:
A- During the flare at thrust reduction select ALL thrust levers to IDLE.
Can any AB pilots explain what it is in the AB operating procedures that makes this warning necessary? Are pilots 'encouraged' to keep their hand off the throttle with the inop reverser?
As someone has said, the 'Swiss Cheese' was perfectly aligned for this one. What a tragedy. Just like the Helios crash.
Zeke: since the Airbus note is the first public pronouncement to apparently benefit from DFDR evidence, I'm sure it is highly significant. The reason for my caveat is simply that in the short term aftermath of an accident and until an objective investigation by an independent party is complete, it is prudent to take notice not only of what is said but who is saying it. So far we have had the airport operator defending the runway condition, the government defending Brasilian safety standards and infrastrucure investment, and the airline defending its maintenance performance. Airbus has in the past been, shall we say, staunch in its defence of its product; one would not expect otherwise. However if there do prove to be similarities with the previous overrun incidents mentioned in this thread, the pilot community will no doubt be equally resolute in exploring the perspective of crews who have been involved in such incidents, including the two individuals who cannot argue their case.
BOAC - I can't think of an Airbus procedure that would require that notice to be issued, but I do know that when working toward the limits of your capacity with the autothrust engaged it is possibile to forget to retard the non-moving thrust levers to idle in the flare, especialy if new to the aircraft.
Following 4HP's post at #424 and the subsequent I feel we really should all wait now for the answer from the FDR which I think will be conclusive.
My only comment would be that, clever as the AB philosophy is, it may be necessary to retain some basic flying techniques in its operation and not be 'seduced' by its 'sophistication'?
What we *don't* know yet about the Congonhas accident:
* Touchdown speed (guessed from video: 130 kts +- 10)
* Touchdown point
* Whether reverse was used (guessed from video: on port)
* What the starboard engine did
* Whether airbrakes (5+5 spoilers) activated
* What braking action was selected (guessed: manual)
* Whether antiskid was activated
Given that we don't even these basic parameters, BOAC's suggestion that we'll just have to wait for the FDR readout seems right on the mark. Until we know these, we can't even begin to judge whether the accident has any causally relevant similarities to any of the other overrun incidents above.
There seems to be some confusion in interpreting the Airbus communication about thrust lever position and exactly how it relates to reverse/autobrake/spoiler behavior in a possible overrun situation. A careful read of posts 424, 426, and some pages of the "GE 536 Occurrence Investigation Report" (link below) from Taipei is informative. The A320 at Taipei landed with #2 reverse disabled, and #2 thrust lever was left at 22.5 degrees after touchdown. Being somewhat above the throttle lever angle defined as "idle", spoiler extension was prevented even though reverse was used on #1. See the ground spoiler extension logic diagrams provided in both the factual and final reports. Autobraking was also suppressed, and diagnosis/response took approx 15 sec before manual braking began. For the busier who don't have the time to read all of it, see Section 2.3 Flight Operations, and Section 2.4 Stopping Distance (pages 83-93) of the final investigation report. This contains a good summary as well as a stopping distance analysis. Note especially in Table 2.4-1 that the combination of delayed braking, no spoilers, and somewhat higher EPR on #2 added up to a required rolling distance of 7800 feet for a 55,000 kg landing weight (although there appears to be some tailwind component). This was more than 4000 feet beyond what would have been required if #2 throttle lever had been closed and autobraking and ground spoilers deployed as planned. The calculations predict the Taipei A/C was at 67 kts at overrun on an 8550 ft (2600 m) runway with touchdown at 1750 ft (533 m), leaving 6800 ft (2072 m) usable.
As has been said before, any relevance to TAM 3054 will have to wait for the final analysis, but Airbus' release of the throttle lever guidance suggests it's important for A3xx pilots to clearly understand the implications.
Most air incidents are caused by five or more reasons.
Therefore:-
The runway was resurfaced incorrectly.
The aircraft was serviced incorrectly.
The weather conditions were below the minima for that runway.
Air Traffic was at fault.
The pilot was at fault.
The Brasiliian authorities were at fault.
This always combines into a tragedy.
There is never just one reason or one person at fault ?
Add to these Taipei and Irkutsk (engine with disabled reverser left in above idle thrust)
You can also group together at least Ibiza and Warsaw with those in that the monitoring pilot failed to recognise that the insufficient deceleration was due to all retarding systems not being fully deployed. But as has already been stated in the thread, with a short runway you just don't have the time to troubleshoot your failing/misconfigured systems before you already run over the end.
Also the Bacolod accident was according to unofficial reports due to one engine throttle not being moved to idle, but that was a fault in autothrottle disengagement and it appears the crew took the right action in shutting the offending engine down, but still ran over the end.
Last edited by EFHF : 24th July 2007 at 16:12.
Reason: Added info about the Bacolod accident
Description Of Fly-By-Wire: (Flight Crew Training Manual A320)
1.The Fly-by-Wire was designed and certified the to render the
new generation of Aircraft
2. Even more safe, cost and effective, and pleasant to fly.
Basic Principles of the Fly-By-Wire:
The Flight Control Surfaces are all:
- Electrically-controlled, and
- Hydraulically-activated
- The Stabilizers and Rudder can be mechanically-controlled
- Pilots use sidestick to fly the aircraft in pitch and roll (and yaw indirectly, through turn coordinations)
- Computers Interpret pilot input and move the Flight Control surfaces, as necessary, to follow their orders.
- However, when in normal law, regardless of the pilot's input, the computers will prevent excessive maneuvers and exceedance of the
safe envelope in pitch and roll axis.
- However, as on coventional aircraft, the rudder has no such protection
GO AROUND IF:
1.Approach is not properly stabilized
2.Doubt about situation awareness
3.Malfunction
4.ATC changes the final approach clearance
5.Adequate visual cues not obtained at MDH or DH
6.Any GPWS/TCAS or Windshear alert occurs.
Consider Engine Damage If you Notice:
1.High Vibration prior to engine stopped, loud noise
2.Stall
3.Any Abnormal On Eng Page (N1, N2~0)
The Questions right now are the ff:
1.Did The Pilots Armed The Spoilers? or they forgot it?
2.When the Aircraft touches on the ground, did the engine suffers a FOD? due to excessive water and other contaminants coming in to the fan blades going to the compressor??? resulting the thrust reverser INOP?
3.Did the Engine Stop During/after the the aircraft touches the ground?
resulting the some hydraulics/electrical system to fail??
4.If the Spoilers deploy during touchdown??
5.Did The Computers take over the commands of the pilot?
1.Did The Pilots Armed The Spoilers? or they forgot it?
2.When the Aircraft touches on the ground, did the engine suffers a FOD? due to excessive water and other contaminants coming in to the fan blades going to the compressor??? resulting the thrust reverser INOP?
3.Did the Engine Stop During/after the the aircraft touches the ground?
resulting the some hydraulics system to fail??
4.If the Spoilers deploy during touchdown??
5.Did The Computers take over the commands of the pilot?
Some answers,
1- Arming the spoilers is part of the final app preparation (gear down, spoilers armed, and lights on). At TAM, there is a FINAL checklist. The items:
- Cabin crew........advised
- Auto thrust.......speed
- ECAM memo......landing, no blue
Landing, no blue means that the landing items are all done (the ECAM memo displays all "essential" items to be armed / prepared for landing. If one forgets to arm the spoilers, the line "spoilers" will be like this:
Spoilers.......ARM (in blue)
So, before the PF calls - landing, no blue - he has to check the ECAM memo. (Sorry my lack of English skills, I hope the answer it is clear enough)
2- FOD is not an issue here, I believe.
3- With flaps extended, the ignition system is on, and therefore, engine failure is unlikely (but it can happen, sure). About the hydraulics, the system has more than 1 pump (one engine pump and one electric pump) and also a PTU, so the complete loss of hydraulic pressure due to engine failure is unlikely.
(Green and yellow hydraulic systems)
4- I never had this problem on the Bus (no spoiler deployment at touchdown).
5- See, there is an "urban legend" about the airbus. There is not such thing as "computers taking over....”
I think it would be beneficial if you could manually extend the flight spoilers with the lever to transfer some weight and at least get the very complex deceleration sequence started. You may do that in config 3 but not in config Full but with short & slippery conditions the extra speed of config 3 is not acceptable.
- At what point (...mm water on the RW) does your company assume
aquaplaning? (one of mine used to be >3mm then they went to >1mm)
- What correction does your company require to be made for aquaplaning?
- Does your company require the ship to be 100% for aquaplaning ops?
- Have you ever asked for the runway state on a rainy summer day and been
greeted by surprise (well sir, it is wet) when you really want to know the
depth of water?
- Have you ever asked for the runway state outside of winter ops? Maybe if
we did that more often airfields would become sensibilised.
- Have all the Airbusses now been modified, so that mainwheel spinup on one
side only will cause spoiler deployment?
Linear Mode
