PIA A310 incident in Pakistan

[barit1]

Found at www.dawn.com :

Plane makes emergency landing at Karachi

Dawn Report
KARACHI/ISLAMABAD, April 17: A PIA aircraft carrying over 100 passengers made an emergency landing on Tuesday at the Karachi airport a few minutes after takeoff.

Three main tyres of the A-310 aircraft deflated during the landing because of excessive brake heating but the passengers and crew remained safe.

The captain of the Faisalabad-bound flight, PK-340, returned and made the emergency landing after the auto-pilot function of the aircraft failed.
The Airbus, AP-BDZ, lost control soon after takeoff and started sinking after attaining a height of about 1,000 metres.

Engineers said that there was a great difference in the sense of air speed from the left and right sides, which disturbed the engine functioning.

Society of Aircraft Engineers, Pakistan, President Shaukat Jamshed said the situation was pretty grave and could have resulted in a disaster.

The nose of the aircraft touched the airfield during the landing, resulting in damage to the nose wheel and windshields in addition to the ruptured tires.
A PIA spokesman said that the captain using manual controls determined that the fault had been possibly caused by erroneous air speed indications and decided to land back.

He said the aircraft had been grounded and a thorough inquiry into the incident was being undertaken. The aircraft would not fly till satisfactory rectifications were made under advice of the Airbus Industries and clearance of the Civil Aviation Authority.

The passengers departed on another aircraft a couple of hours later.
Sources said the Airbus had suffered similar problems twice during the past six months and PIA had carried out rectifications in consultation with the manufacturer.

“The aircraft has a nose-down tendency,” they said, adding that the problem could not be precisely located on previous occasions. Experts said the aircraft would now require non-destructive testing. It was commissioned in March 1991.

That "nose-down tendency" - better look out for that --

[Bob Lenahan]

In my first hours of flight instruction I was taught to never let the nose touch the airfield.

[fyrefli]

The nose of the aircraft touched the airfield during the landing,

“The aircraft has a nose-down tendency,” they said

Sounds like an early candidate for understatement of the century!

[crazy_pilot]

confused, if the nose of the aircraft touched the airfield during the landing then how aircraft landed safely?

[Sallyann1234]

Caution! - newspaper report!

[Thylakoid]

I flew A310 for four years. Never trusted the thing. Many funny things would happen, out of the blue. ECAM system was pretty much of a hindrance than of a helper in abnormalities. Unstable piece of iron. Stay away from her; from all airbusses, by the way

[bri1980]

In general the A-310 doesn't have a nose down tendency. Perhaps someone does not know how to load it properly!

The story seems a bit suspicious to me: the nose touched the floor? Hard to see how this could happen unless the nose gear gave way as well.

[AN2 Driver]

Yea, newspaper report, but a few interesting bits in there which could explain at least why the plane got into quite some trouble.

Engineers said that there was a great difference in the sense of air speed from the left and right sides, which disturbed the engine functioning.

Now that one has been known to be a killer before. I seem to recall Birgin Air and LAN Peru (both 757's) getting into fatal situations on such an occasion. I think they both had static ports blocked but the result was a lot worse.

Not sure how the A310 reacts to severe differential ADC outputs, I might imagine if one shows overspeed and the other stall (as happened in Birgin Air as far as I recall) the DFGS and the protection envelopes might become rather confused? Need to read up on what could happen but I think it might not be pleasant.

Nose down tendency and the likes, what about trim runaway to nose down and/or protective devices coming in due to the false IAS?

All speculation on my part (not very educated as I don't have any A310 books handy where I am now) but food for thought?

Best regards
AN2

[tubby linton]

The A310 Fcom chapter on flight instruments is here:http://www.smartcockpit.com/pdf/plan.../systems/0011/
The file is large so may take a while to download!!

[hetfield]

@AN2 Driver

Nose down tendency and the likes, what about trim runaway to nose down and/or protective devices coming in due to the false IAS?

Manual flight - (almost) no protections

[tubby linton]

Here is a link to the pitch trim protections.They are generated by the FACs,which in turn gets airspeed info from the ADCs.
The FACs operation is very poorly covered in the Fcom even though they have numerous functions .They also have no isolation capability apart from circuit breakers.
http://www.smartcockpit.com/pdf/plan.../systems/0010/

[AN2 Driver]

Thanks guys.

Will dig out my AOM's once I get back home....

Best regards
An2

[cwatters]

“The aircraft has a nose-down tendency,” they said,

Reminds me about an incident involving a screw jack and a lack of grease or something. I wonder if they are looking at the right end of the plane?

[J430]

hetfield Quote:
Nose down tendency and the likes, what about trim runaway to nose down and/or protective devices coming in due to the false IAS?

Manual flight - (almost) no protections

Come on guys...........manual flight, if you have an ATPL ticket you should be fine with hand flying any servicable aircraft, with or without all the computer F#$% Up protections. No excuses.

J

[cargo boy]

Come on guys...........manual flight, if you have an ATPL ticket you should be fine with hand flying any servicable aircraft, with or without all the computer F#$% Up protections. No excuses.

Ah, the voice of a 'theorist' who has probably never even trid it in the sim with two ADC's giving conflicting data.

Why do these people always jump in with their assumptions that it was just a case of looking out of the window and flying it by the seat of their pants? I'd like to see anyone, no matter how experienced try and fly a heavy jet with unreliable airspeed and the added confusion of contradicting warnings such as low and high speed stick shaker and mach clacker going off at the same time.

Also, how do you know they didn't have a runaway trim? I'd like to see the armchair 'hindsight heros' like J430 fly a jet with trim and indication problems. Probably relates it to flying a light twin or a single engined prop!

[hetfield]

@J430

I'm afraid you didn't get the problem.

[llondel]

never even trid it in the sim with two ADC's giving conflicting data.

You almost want to have a third set of sensors and instruments fitted somewhere so that if the two disagree, a deciding vote is available. However, I can think of a few incidents where the third one would have disagreed with both the other two, giving a choice of three different ones instead of two.

[J430]

OK guys take a chill pill.
Comment was directed, almost tongue in cheek at the manual flight - no protections comment.
Not at what the perceived or actual problem was. I did qualify by saying any servicable a/c, Stop jumping to the defensive!
J

[tubby linton]

Has anybody managed to source a picture of the damage yet?

[Ultralights]

whatever happened to the days of analogue backup!