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Really Hard Landing 3.5g

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Really Hard Landing 3.5g

Old 23rd Dec 2017, 15:34
  #81 (permalink)  
Join Date: Jan 2010
Location: England
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Those suggesting they might not know it's 3.5g have their head in the clouds.

Worst I've done (and been party to) is 1.7g, and I thought I'd snapped the wings off. I can't imagine how 3.5g must feel.
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Old 23rd Dec 2017, 19:22
  #82 (permalink)  
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Skittles - couldn't agree with you more! I remember sheepishly following my Captain to the fleet manager's office (voluntarily) many years ago because we thought we'd done a REALLY hard landing. He had the data interrogated - surprisingly it was only a 1.4G landing! I was dumbfounded then (as I am now) how some pilots fail to notice a 'true' hard landing.

The FD conversation on this thread is also interesting. I found that only after I'd flown a large Boeing did I truly understand how to fly a FD on final - and it was this; never slavishly follow the FD! Instead take the 'hint' that it's giving, i.e. if it shows a 'fly up' command, just a gentle pitch correction TOWARD it is sufficient to see it immediately come back down towards commanded pitch.

While a line instructor, it was something that I tried very hard to instill in new Airbus pilots. As an examiner, I tried to encourage the adoption of same in those who showed a tendency to pitch inappropriately (by simply following the FD like their lives depended on it).

As for autothrust - I think the AB certainly does a great job of maintaining speed on 90% of approaches. It's when the 10% of flights encounter seriously gusty conditions that I believe manual thrust comes into its own. Sadly there are an ever-increasing number of airlines who mandate autothrust ON unless it fails - so it becomes harder to fly the aircraft smoothly in those conditions.

What to do, what to do?
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Old 23rd Dec 2017, 21:09
  #83 (permalink)  
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I think of the FDs as suggestion bars

And I'm a big advocate for manual thrust on the bus, time and a place etc.
Particularly given the response of the a330s ATHR system
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Old 23rd Dec 2017, 21:46
  #84 (permalink)  
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I'm also with Skittles on this one.

The aircraft was planted by the F/O and we had an ACARS reading of 2.1G. Subsequently the Engineers determined that it was only 1.7G because the aircraft looked at the difference between the positive and negative 'G' - apparently.

During the taxi in I was in shock to be honest, as was the F/O. The poor F/O was actually in tears at the gate.

I had thought that there must be damage although a post flight walkround revealed nothing to me. We nightstopped for the Engineer to do inspections which revealed nothing amiss.

Anyway, how any crew could think that 3.5G is nothing to worry about is beyond me.

By the way I was dragged into the office and given a dressing down about allowing an F/O to carry out a night landing off an NPA. Maybe they were correct, although it had never happened before or since.
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Old 23rd Dec 2017, 23:39
  #85 (permalink)  
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I suggest whoever called you into the office never travel on an airline based on the west coast of the Atlantic. Being a copilot at that company must be a very boring job.
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Old 24th Dec 2017, 10:37
  #86 (permalink)  
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From an engineering point of view, I suspect that if you load a 'plane up to twice its weight, to simulate 2G, then the MLG would be fully compressed. Any further loading beyond that will result in the shock going straight into the airframe, as the shock absorbers are beyond their working range.

Also because the CofG is in front of the MLG, the landing impact will cause the front of the aircraft to drop (lessening the G in the cockpit area.) and cause the rear of the plane to rise, increasing the G forces on the tail. All this rather begs the question of where do you put the Accelerometer to record the forces, or maybe use several of them and take the highest reading.

I think for certification reasons all aerobatic airplanes must have both a 5 point seat harness, and a recording G meter. This will have moving needles for +ve and -ve G, and is fitted into the instrument panel.

Last edited by scifi; 24th Dec 2017 at 14:34.
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Old 24th Dec 2017, 15:04
  #87 (permalink)  
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I’m sure I remember that back in the day, “crush tape” was fitted to the base of the MLG struts. If it was crushed, it was a heavy landing and inspection was required. (Simples!)
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Old 2nd Jan 2018, 13:48
  #88 (permalink)  
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Originally Posted by cessnapete View Post
Unfortunately its not just small Airbus operators mandating these SOPs.
Apart from the B744, British Airways SOP bans manual control of thrust management on all fleets,at all times during route flying.
Although I dont doubt your words, I am quite surprised to learn that a reputable airline with a heritage such as BA comes up with that kind of SOP.
Never understood the rationale behind crippling pilot skills when all interest should be in keeping those skills sharp.
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Old 3rd Jan 2018, 08:32
  #89 (permalink)  
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Think you will find that the wings are still carrying a lot of the load in a normal but high ROD landing. Modern airliner struts do not just bottom-out except in extreme overload, they get very stiff in the latter part of their range to avoid destructive structural failure from a high ROD touchdown, esp below normal MLW, although progressive overload damages will occur with the severity of overstress. The "question" of measuring loadings and their interpretation, has also been long understood for airliners.
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Old 14th Jan 2018, 19:45
  #90 (permalink)  
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my airline was the first NA carrier to fly the 320 and the 747-400, and, back in the day, the more we got of each, the more the airline's training dept (unofficially, as I remember it) encouraged the occasional use of manual thrust. (so as to maintain FLYING skills). But the airline didnt mandate either, unless required--obviously.

I cant imagine why manual thrust should be prohibited in line training? so, the first time I get to do it is, unsupervised?

how about, say, landing in sfo, lets try it there the first time.
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Old 16th Jan 2018, 19:08
  #91 (permalink)  
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Generally, our rear quarters are calibrated on the safe side of the G meter. On transport aircraft, it is very common for the pilots to note a hard landing before the accelerometers tell their story - i.e., maintenance nearly always has log entries of perceived hard landings that were within parameters rather than the other way round.
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Old 17th Jan 2018, 10:26
  #92 (permalink)  
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I would agree. However, the danger lies in the unchecked actual overstress. The further operation of this aircraft before being properly heavy landing checked is a criminal act IMO.
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Old 17th Jan 2018, 10:39
  #93 (permalink)  
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Clue to a serious "event" is that the "rubber jungle" deploys.
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Old 17th Jan 2018, 20:05
  #94 (permalink)  
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Reading a Load 15 report is a notoriously dark art.
Airbus, in its wisdom, made it hellishly complicated.
Interpreting the report is tricky due to the multiple combinations of parameteters and the timings of events. The touchdown point is often difficult to judge from a bunch of digits.

It isn't just all about G loading either. In fact Vertical Acceleration coupled with pitch/roll angle play as big a part if not greater in some cases.

Most airlines I have worked with leave it to the Captain to determine if a Hard Landing has occurred (a heavy or overweight landing is a completely different animal) however, when an automatic report pops out of the printer we usually get a call just to make sure.

In this case I do wonder what was uppermost in the minds of the crew....

Last edited by TURIN; 17th Jan 2018 at 21:36. Reason: clumsy grammar
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Old 17th Jan 2018, 21:16
  #95 (permalink)  
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Originally Posted by TURIN View Post
It isn't just all about G loading either. In fact Verical Acceleration and pitch/roll angle play as big a part if not greater in some cases.
It's not only G loading, it's vertical acceleration as well ?
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Old 17th Jan 2018, 21:37
  #96 (permalink)  
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Changed it now. Does it make more sense? It's late and i've had gin.
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Old 18th Jan 2018, 08:56
  #97 (permalink)  
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vertical acceleration and g-loading is one and the same. 1g=9.81 m/s^2

you probably meant sink rate?
that gives a good picture of kinetical energy absorbed by the system.
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