Lion Air flight JT610 crashes into sea after take-off from Jakarta...

[Altamira]

What is a pitot tube? How does it work?

Covers the air speed indicator when the plane is left for any length of time in tropical climates... apparently wasps like to build mud nests in them which has been the root cause of a number of accidents over the years.

See detailed ATSB investigation:
Investigation: AO-2018-053 - Airspeed indication failure on take-off involving Airbus A330, 9M-MTK, Brisbane Airport, Queensland, on 18 July 2018

What is a pitot tube? How does it work?

Covers the air speed indicator when the plane is left for any length of time in tropical climates... apparently wasps like to build mud nests in them which has been the root cause of a number of accidents over the years.

See detailed ATSB investigation:
Investigation: AO-2018-053 - Airspeed indication failure on take-off involving Airbus A330, 9M-MTK, Brisbane Airport, Queensland, on 18 July 2018

Just a little clarification on the above statements. The pitot tube or pitot static tube is not an airspeed indicator, but rather an essential component of the aircraft's airspeed sensing system. It is a tubular device, usually attached to the aircraft fuselage, and is used to measure the differential pressure between the air flow pressure coming into the pitot tube as it moves through the air column and the static pressure. This pressure differential, or dynamic pressure, is used by other aircraft systems to determine the aircraft's airspeed. A cover is normally put on the pitot tube as a protection to keep bugs and debris out of the pitot tube when the aircraft is parked for a relatively long period of time, such as overnight or extended ground time in any climatic environment.

 

[flyboy08]

Pitot or not, I wouldn’t speculate one way or the other now! And who needs a pitot tube in day VFR? Airspeed and attitude should be second nature to a seasoned pilot in DVFR! Besides, the plane has an electric backup AI!

Alaska Air had a similar loss a few years back....seems awful similar...MD83 though.

 

[Steve_C]

There was a similar loss in South America a few years ago. A ground crew doing some cleaning left covers over the tubes.

 

[TrimixToo]

Just a little clarification on the above statements. The pitot tube or pitot static tube is not an airspeed indicator, but rather an essential component of the aircraft's airspeed sensing system. It is a tubular device, usually attached to the aircraft fuselage, and is used to measure the differential pressure between the air flow pressure coming into the pitot tube as it moves through the air column and the static pressure. This pressure differential, or dynamic pressure, is used by other aircraft systems to determine the aircraft's airspeed. A cover is normally put on the pitot tube as a protection to keep bugs and debris out of the pitot tube when the aircraft is parked for a relatively long period of time, such as overnight or extended ground time in any climatic environment.

Hm. Let me try.

A pitot tube projects into the airstream with a tube parallel to the airstream. It has a forward opening that provides a positive pressure source used by the airspeed indicator in the cockpit. An accompanying static tube has an opening at right angles to the airstream and provides a "neutral" pressure source to the airspeed indicator. Sometimes the two are integrated in a single assembly, and sometimes they are separated. Any obstruction of either tube will cause an inaccurate reading for *one* airspeed indicator. (There are at least two on a commercial airliner. On, say, a small Cessna or Piper there is only one, but you can judge airspeed much more easily in one of those than in a jet.)

The airspeed indicator itself is merely a differential pressure gauge. Many are similar in type to the Magnahelic gauges used to measure cracking pressure for regulators, but they are calibrated in knots in a range appropriate for the aircraft in which they are installed rather than in pressure units.

A pitot tube cover is indeed used to protect a pitot tube from foreign object incursion. Such a cover might or might not cover the static tube as well, depending on whether it is separate from the pitot tube or integrated with it. With the cover in place, I would expect the airspeed reading to be zero at any speed, but since they have big red "Remove Before Flight" streamers on them I always removed them during preflight and never actually tried it. I rather doubt that anyone missed a minimum of two big red streamers on preflight, but who knows? Anything is possible, I suppose.

 

[flyboy08]

Hm. Let me try.

A pitot tube projects into the airstream with a tube parallel to the airstream. It has a forward opening that provides a positive pressure source used by the airspeed indicator in the cockpit. An accompanying static tube has an opening at right angles to the airstream and provides a "neutral" pressure source to the airspeed indicator. Sometimes the two are integrated in a single assembly, and sometimes they are separated. Any obstruction of either tube will cause an inaccurate reading for *one* airspeed indicator. (There are at least two on a commercial airliner. On, say, a small Cessna or Piper there is only one, but you can judge airspeed much more easily in one of those than in a jet.)

The airspeed indicator itself is merely a differential pressure gauge. Many are similar in type to the Magnahelic gauges used to measure cracking pressure for regulators, but they are calibrated in knots in a range appropriate for the aircraft in which they are installed rather than in pressure units.

A pitot tube cover is indeed used to protect a pitot tube from foreign object incursion. Such a cover might or might not cover the static tube as well, depending on whether it is separate from the pitot tube or integrated with it. With the cover in place, I would expect the airspeed reading to be zero at any speed, but since they have big read "Remove Before Flight" streamers on them I always removed them during preflight and never actually tried it. I rather doubt that anyone missed a minimum of two big red streamers on preflight, but who knows? Anything is possible, I suppose.

How about when your instructor places clear tape over it....and then while your barreling down the runway without airspeed and your instructor sez....what now? I rotated....lol! Brought her around and landed safely ...that was a payback.

 

[chillyinCanada]

https://beta.ctvnews.ca/content/ctvnews/en/national/world/2018/11/1/1_4158603.html

 

[Dan]

It’s good to hear that a diver recovered the black box. Hopefully we’ll know the root cause of the accident soon.

It’s hard to believe such accident happened to a 2-month old airplane with only around 800 hour flight time.

Condolences to the family & friends of the deceased.

 

[Altamira]

The black box is only one component of a complete flight accident investigation. It alone, generally will not tell investigators what series of events actually caused the accident, and considering the aircraft hit the water, I would not be hopeful for a quick accident report.

 

[flyboy08]

The black box is only one component of a complete flight accident investigation. It alone, generally will not tell investigators what series of events actually caused the accident, and considering the aircraft hit the water, I would not be hopeful for a quick accident report.

Not sure where you got your info from? The black box, which is actually orange, will show 1000 of parameters from engine start to accident site and often can offer enough information that the NTSB, or equivalent authority can determine cause.

 

[Lorenzoid]

Not sure where you got your info from? The black box, which is actually orange, will show 1000 of parameters from engine start to accident site and often can offer enough information that the NTSB, or equivalent authority can determine cause.

Maybe Altamira is referring to the additional information that might be provided by the Cockpit Voice Recorder? As I understand it, the Flight Data Recorder and Cockpit Voice Recorder are the two main sources of information that investigators would rely upon in determining a cause.