I fly AB from a to a short rwy (flr) and we and a "no dispatch" policy in that apt whith 1 Rev inop. :ok::ok:
-Recently I had a Rev fault indication that the tec found was related to a faulty proximity sensor in the main landing gear strut and not to a Rev imself. Interesting noting that some braking issue also led to a rev inop. So could be nice to know if the Rev inop in the Tam was due to actually a faulty Rev or perhaps to other reasons.

Jersey 27 is very similar and 1000ft shorter!! Frequently accepts B737s and A320s even the odd A321.

I was there a few weeks ago watching planes land in heavy rain whilst waiting for my flight back to East Mids. It was tight!!

Could someone clarify

With one reverser inop would standard practice be to land and use the one remaining, with acceptable asymmetry, or to use neither ( or even to use one at idle only)

Guess too early to speak about FDR / CVR recovery as the crash site is not yet fully secured but just wondering how long they can survive in a fire environmnet. I know that regulations call for 1100 degC / 30 min... no idea if this will be good enough here...

22/04 - On a normal runway, up to full reverse on one side is controllable and used as 'standard' in the event of an engine out landing on a two-engined a/c.

Atakacs - The pics I have seen show the tail section reasonably intact, so hopefully they will be ok.

Doors to Automatic
 

No, Jersey 27 is not 'very similar', it's like comparing apples with Oranges. At least one big difference is that Jersey is not far off Sea Level whilst Congonhas is about 2500' AMSL.

What difference does that make to braking capability?

A quick 'advisory' here - I'm as guilty as anyone, but we need to keep this thread focussed on the accident rather than discussions about other airports. Maybe we need a new thread about over-run areas?

an airport at 2500 feet vs sea level and landing distances...

an airplane needs to approach a field at an indicated airspeed based on weight (additivies for wind)...that speed is the same regardless of elevation of the airport

but here is the rub

if the indicated airspeed is the same at sea level and 2500 feet...the TRUE AIRSPEED is higher at 2500feet/ this means a higher ground speed and a longer landing run than at sea level.


google things like ''density altitude'' or "high density altitude" for greater details.

note; HIGH density altitude does'nt mean that the density is high!

Doors, in other words, and put very simply, you end up landing faster at the higher airfield.

I was just wondering what effect that one reverser inop could have had in the deceleration and had it made a significant difference in the actual stopping performance (regardless of what effect it had in the large left excursion from the runway C/L or in the possible fatal decission to attempt a G/A).

Considering the ALD calculations here, with -6 % for two reversers (and implying at most -3 % for one) in case of MAX manual braking (with ca. 2000 feet to spare) and here from another source of -9 % for MED autobrake with 1/2" water (giving ca. 340 feet to spare), I don't see how having one more reverser could have saved the day from the deceleration alone.

In another A320 overrun accident (page 78, figure 2), which was due to complete brake failure, the average deceleration attained from aerodynamics and full reverse was just 0.9 m/s2 (about 0.09 G), with the aircraft leaving the pavement at about 55 kts after a ground run of 2000 m (ca. 6500 feet).
In other words, if you are getting insufficient deceleration from the braking due to whatever causes, aquaplaning, chemicals dissolved by rain, etc., reverse thrust is probably not going to make the critical difference between a high speed overrun or just a close call, at least in jets like A320.

Whilst completely true, this answers a question which Doors to Automatic did not ask. His question was:

I would think the answer is not much difference to braking by the wheels, though any aerodynamic braking would be reduced. This would probably have only a marginal overall effect on the braking, on a like for like speed basis.

Of course, this ignores aquaplaning, which could also be affected by density altitude. Not knowing of any effect this might have, my first hunch would be that the relatively greater tyre pressure compared to the ambient might even reduce the speed at which aquaplaning occurs, thus helping to reduce stopping distance.

Anyone with greater knowledge and FACTS care to enlighten us?

PM

Atakacs
FDR and CVR were sent to the US last night 19 July.

Thanks guys - I obviously know that the higher you are, the less effective engines (and therefore reversers) are, but I didn't know the approach speed was higher. In this business you really do learn something new every day! :p

I remember seeing a documentary about some porous concrete that was used to pave the last few dozen yards of a runway somewhere. If an airplane overran the runway the nose gear would simply crush the concrete and gradually sink into it resulting in a safe, if somewhat abrupt, stop.

As a humble piece of SLF, I wonder why such safety measures are not mandatory at all airports or at least airports like this one.

Oops... missed that one. Any idea if they where in good shape ?

alex

See here for overrruns and crushable concrete. This presumes you have the available space at the airport - not so in this case!

http://www.faa.gov/news/fact_sheets/...fm?newsId=6279

Excellent 8 minute Video here.

http://www.esco.zodiac.com/documents/video/ESCO-lrg.ram

Atakacs - did you miss this one too?:)

Because it costs money and nobody wants to pay.

TopBunk:

The A320 will activate the approach automatically at the DECELERATE pseudo waypoint. So, even if they forgot to manually activate the approach phase, it would have been activated automatically by the time they reached the FAF.