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Oops! BA804 LHR>BLL slight mishap taxying in this morning ...

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Oops! BA804 LHR>BLL slight mishap taxying in this morning ...

Old 8th Feb 2017, 22:20
  #41 (permalink)  
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Understood, wiggy, but does this count as credible?

Possibly not been a good year for that airframe?
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Old 8th Feb 2017, 22:52
  #42 (permalink)  
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Time will tell, I really don't know. The "ba source" is generally pretty reliable but it's interesting they are claiming it was a nosewheel steering "issue", whatever that is, on the same day the incident occured. Then again that description could be a catch all to cover anything from a mechanical defect to the nosewheel steering not working due a lack of traction.

As for it being a bad year for the airframe it's interesting to type in the other BA 320 registrations to get a comparison.
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Old 8th Feb 2017, 23:03
  #43 (permalink)  
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Originally Posted by wiggy View Post
As for it being a bad year for the airframe it's interesting to type in the other BA 320 registrations to get a comparison.
Quite so.

For example G-EUPJ comes up with 50% more issues on thebasource.com.

It's in the nature of aircraft operations and maintenance that not all of the fleet will accumulate occurrences at the same rate. Trying to read anything into that is pretty meaningless.
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Old 9th Feb 2017, 00:20
  #44 (permalink)  
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Meaningless if you are not a statistician, or a fleet manager in possession of the full SP perhaps?

Yup, 'tis true that in this rudimentary test, G-EUPJ yields 50% more "issues" recorded on thebasource.com spread over 5 years than G-EUPM, but notably 17% less than G-EUPM over the time period of all issues recorded by thebasource.com for G-EUPM.

G-EUPM's all occur in just over the past year. How weird is that?

Actually to be balanced about it, there was one more for G-EUPJ in July 2015 that falls out if you use "incident" as opposed to "issue" in your search

I must admit that since I had found this interesting way to search at tea time today, (which I can see you guys have had fun with now too!) I was myself planning on trying one or two other reg numbers of A319/320/321 for comparison. But it was past tea time for me. I did in fact type in one random BA reg no for another type entirely before I bogged off for tea and telly which was the first one that I stuck a pin into mentioned on thebasource.com front page today. That yielded a statistically less significant three "issues" over 5 years.

So what is it about the A319 type that causes so many "issues", especially in the last 12 months for these two aircraft that were both delivered 17 years ago? Bad luck?

Actually of the 44 (?) on the fleet of BA A319s, a search of thebasource.com for a319 issue yields 394 hits - an average of 8 hits per airframe. I haven't found a simple way yet to find the average over a set period.

A search for a319 incident yields just 10 hits including two mentions of the Billund yesterday (one tells us that Jettime Boeing 737-3YO OY-JTD operated as BA805 yesterday in place of G-EUPM; another two hits refer to G-EUPJ smoke in the cockpit in 2015; and another three out of the 10 refer to the memorable G-ErrorsUndOmmissionsExcepted LHR cowling problem in 2013).

A320s and A321s seem to do better on the 'issue' score at something over 5 hits per airframe average.

The two A318s I guess have to be spot on at all times for ETOPS so no surprises there that there are 19 hits for issues between those two since 2014.

So, all in all, yes pretty meaningless - except to those who hold more information and can go digging if so disposed
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Old 9th Feb 2017, 08:05
  #45 (permalink)  
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In my experience, examination of the technical records for those Airbuses (or any aircraft, come to that) would reveal many dozens, or even hundreds, of "issues" over the years.

Here, we're relying on a blog that, by definition, only focuses on those occurrences that have an external impact (flights delayed or cancelled, forced returns, etc) and therefore only reports on a minute proportion of the total.

That doesn't fit any definition of "statistically significant".
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Old 9th Feb 2017, 08:14
  #46 (permalink)  
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Here, we're relying on a blog
Point well made, and perhaps one I should have made earlier when I was effectively asked if the BA source was credible.

AFAIK whilst the BA source is excellent for many things it is not an official organ of the company and AFAIK has no official feed from company sources, though it times it is remarkably well informed in some areas. TBF if you look at the website's header it does make it clear it is an unofficial blog.
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Old 9th Feb 2017, 12:30
  #47 (permalink)  
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For those that haven't seen it here's a demo of how easily your day can go wrong when there's snow and ice around.

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Old 9th Feb 2017, 14:07
  #48 (permalink)  
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Back to the frozen north I see at minus 20 degrees C ! But ok it is a salutary warning of what can happen on black ice without skidpan training
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Old 9th Feb 2017, 16:55
  #49 (permalink)  
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I have on atleast three occasions while taxiing very slowly when without a hint of warning I become a passenger on a jet that a split second ago I was controlling. The worst of it is there is not a clue when the combination of ice, taxiway slope, and wind forces combine with the lack of friction and the inertia to take control from you.
This. Exactly this. I HATE taxying on ice or snow and am quite proud to be the slowest aircraft on the airfield.
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Old 9th Feb 2017, 17:55
  #50 (permalink)  
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I spent a fair amount of my life flying around Scandinavia at night in the winter. I will say straight away that when it comes to snow clearance, they make us Brits look like very poorly-equipped Boy Scouts. However, there can be some occasions up there when clearing the runway (quite correctly) gets priority over the ramps and the taxiways.

In particular, I can remember landing off a CAT II approach at Landvetter one night and tiptoeing down the taxiway at a snail's pace to the ramp. Fortunately the ramp is a big place there and there was nothing in the way for I lost it and we ended up sliding sedately sort of sideways for about 100 metres or so before I recovered my presence of mind.

So, I have to tell you my favourite Billund story. One of my mates arrived there in the early hours of the morning. It is snowing and snow clearance is in progress. There is also a 30 knot northerly wind blowing (the runway is/was 09/27 and about 9,000 feet long).

He is looking at the fuel so he asks how they are getting on.

"We have cleared half of the runway and the braking action is good".

Get the books out, no problem, we can stop in half the runway so they start an ILS. Halfway down, my mate asks which half they have cleared?

"The North Half" came back the reply! So he now has 9,000 feet by 75 feet instead of 4,500 feet by 150 feet (don't forget the 30 knot crosswind)!

So, "Don't Assume, Check" is always a valid process.
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Old 10th Feb 2017, 08:46
  #51 (permalink)  
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Could have been worse, they could have replied "The Western half"
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Old 10th Feb 2017, 10:59
  #52 (permalink)  
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Same discussion in the cockpit when the report of xx% bare and dry in the US was received. Dunno if that is still used there, I was always cautious when hearing this, it meant nothing to me.
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Old 16th Feb 2017, 20:40
  #53 (permalink)  
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Interesting: and not wanting to make light of the incident. SAS should be well skilled in such environment, but the apron seems more suited for Torvill & Dean than Boeing. What was the wind, I wonder? The ground vehicles seem OK, but then the would have 'winter snow tyres' & I guess Boeing don't do those.
I wonder what the side load was on the gear. The anti-col light went off just as they stopped. I wonder what they had done to the engines. I'd imagine they'd waited to see where they were when the world stopped rotating. Did they shut down during the pirouette and still have the thought to switch off the anti-col? Cool dudes if they did.
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Old 17th Feb 2017, 08:32
  #54 (permalink)  
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There was a 747 blown off a taxiway in Anchorage in the 80s...had problems controlling it in a strong wind and decided to shut down the engines...game over.
Interestingly BA had different contamination limits to Swissair and operated into Zurich when all of SR's fleet were grounded...work that one out!
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Old 17th Feb 2017, 16:00
  #55 (permalink)  
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It would take an unusual combination of factors to leave the aircraft in the situation it is pictured in if there were no failures, therefore I'll throw my best Sherlock Holmes in to the mix...

Presence of steps at the rear door suggests engines shut down, also spoilers 1/3/5 extended. Now, having at one point made the mistake of shutting down after landing but forgetting to disarm the spoilers, my experience is that all the spoilers stayed up and in order to retract them, it required the Y ELEC pump on with PTU left in auto (that sorted 1/2/4/5) then B OVRD to retract 3. If one wanted to only retract 2/4, that would require both engines off (to avoid B operation), Y ELEC pump on and either PTU OFF, inhibited due to certain criteria being met, or green system failure.

The logic diagram for the PTU suggests that it should run the G system if the Y pump is run on the ground with both ENG masters off, and the NLG shock absorber extended (which can't be clearly seen but best guess is that the nose gear looks like it's still properly extended).

In a roundabout way, and at the risk of being told to wait until the facts come out etc. how about the following as an armchair guess?:

- Aircraft lands normally, ground spoilers all extend.

- Aircraft vacates runway, all spoilers still up, then before 'after landing' actions take place (inc. disarming spoilers) suffers G system problem (LO LVL, LO PR?) and therefore loses control of steering.

- Skids to a halt in the position shown given the slippery conditions. Crew runs through the ECAM, inc. PTU off, decides to shut down in situ, performs the after landing/parking checks but for whatever reason misses the check of spoilers disarmed (lever sitting up only slightly, small note on the ECAM memo lost amongst other items relating to the failure?)

- After shutdown, crew becomes aware of the extended spoilers and decides to disarm the lever and run the Y ELEC pump. This has the effect of dropping spoilers 2 + 4 only.

OK, I'll don my helmet but if nothing else it does the grey matter good to think about the system architecture, I certainly can't come up with too many obvious scenarios that would lead to an aircraft parked half on the grass with spoilers 1/3/5 extended.
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Old 27th Oct 2019, 21:49
  #56 (permalink)  
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Has the AAIB report for this incident seen the light of day or are Airbus still coming up with something?
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Old 27th Oct 2019, 22:56
  #57 (permalink)  
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I see a BA 767 positioned to BLL late last night
I wonder where they got that from? The last of their 767s went to the scrapyard some months ago.
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Old 27th Oct 2019, 23:10
  #58 (permalink)  
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Would the plane be capable to taxiing over the solidly frozen ground without any damage?
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Old 27th Oct 2019, 23:45
  #59 (permalink)  
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Originally Posted by KelvinD View Post
I wonder where they got that from? The last of their 767s went to the scrapyard some months ago.
In 2017 when the post you quote was written BA still operated the 767. It sometimes helps to check dates on posts before commenting.
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Old 28th Oct 2019, 15:51
  #60 (permalink)  
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CEJM: Apologies. You are quite right. I hadn't noticed the dates and assumed it was referring to current events. As you say, I should have checked.
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