Monday, October 9, 2017

MH370: The Continuing Saga

"In January of this year the Australian Transport Safety Bureau (ATSB) decided that the search for MH370 should be terminated.
Their reported statement said:

The Australian Transport Safety Bureau (ATSB) released the final report, summing up the already concluded search of the missing Malaysia Airlines flight MH370, which vanished in 2014 on its way from Malaysia to China.  The authority states that “the understanding of where MH370 may be located is better now than it has ever been”, as the government of Malaysia continues the search.
“The reasons for the loss of MH370 cannot be established with certainty until the aircraft is found,” a statement by the Australian authority claims. “It is almost inconceivable and certainly societally unacceptable in the modern aviation era with 10 million passengers boarding commercial aircraft every day, for a large commercial aircraft to be missing and for the world not to know with certainty what became of the aircraft and those on board”.
The ATSB, which seized its search of MH370 in January 2017, states “our deepest sympathies to the families of the passengers and crew on board MH370. We share your profound and prolonged grief, and deeply regret that we have not been able to locate the aircraft, nor those 239 souls on board that remain missing” in the final report.
The Australian authority body claims that it the possible location of the missing MH370 is now identified to be within an area of less than 25,000 square kilometres. Despite Australia’s withdrawal from the search party, the Malaysian government is continuing the effort, as “their investigation of the facts and circumstances surrounding the loss of MH370 aircraft consistent with their obligations as a member State of ICAO”, according to ATSB.
Malaysia Airlines flight MH370, en route from Kuala Lumpur to Beijing, disappeared from radars on March 8, 2014, less than an hour after takeoff. There were 227 passengers and 12 crew members on board the Boeing 777 aircraft. So far, several pieces of debris suspected to come from the aircraft have been found at different locations, including in Mozambique, South Africa and the French island of Reunion.
Australia commenced the search for it since March 8, 2014 until January 17, 2017 – a total of 1,046 days. It is estimated that the search for the missing plane lasted for 3 years and cost at least $160 million for Australian, Malaysian and Chinese governments."

[The actual full report from the ATSB can be read here:
https://www.atsb.gov.au/publications/investigation_reports/2014/aair/ae-2014-054/]

The way the article (above) is written implies that the Australians have 'given up'. This is not quite true. It was agreed at some point earlier on in the search for MH370 that the search would be discontinued at a specific point. That point was reached in January 2017.
The Malaysian Government, as can be seen from the full report, is continuing its search under the requirements of ICAO (the International Civil Aviation Organisation, which is a United Nations body located in Montreal in Canada).

It is articles like this one that tend to give a somewhat slanted view to the situation. It is that view that could, potentially, give rise to conspiracy theories.

Remember the original statement in this 'Blog'?
"MH370 has disappeared. We know neither what happened nor where it is."
Observe that, at the end of that last sentence, there is a 'full stop'. That is the point at which the conversation ends - until we get more evidence.

Facts. We do not have facts.
Do not make up stories to fit the facts that we do not have!


Wednesday, January 27, 2016

Air




Air. Funny thing, air.
Once upon a time, during a practice oral examination for a gas turbine test, I asked a young lad what the diameter of a ball of air that weighed 10lb would be—roughly.
He looked at me like I had just fallen out of a tree and said, “Air doesn’t weigh anything.”
My turn to look askance.
“Suppose,” I asked him, “I drew a square on the sand down at the beach. A square with each side exactly one inch long. What would the air pressure be on that square?”
“15psi,” he said with supreme confidence.
“Correct,” I told him, “So that picture I have drawn is one square inch—what is the weight of air that is sitting on it?”
He was now bemused. He had no idea how to correlate between pressure and weight per area. Pressure is pressure. 15psi--pounds per square inch, at sea level (ISA SL = International Standard Atmosphere at Sea Level) is what you get; there is no way to rationalise between that and weight of air. Weight is a different thing entirely, it seems.

Another thing is humidity.
Humidity is a difficult thing to imagine. People often confuse ‘vapour’ with ‘steam’ but ‘vapour’ is gas whereas ‘steam’ is minute droplets of liquid.
Water vapour is gaseous water that merges with the atmosphere and can make the air ‘wet’. If the air is saturated with water vapour then, when you sweat (or ‘glow’, if you are one of our gentle female colleagues) it just runs off you and will not evaporate into the air around you.
Dry air is more comfortable for humans if you are from a dry part of the World.
To tell if your air is humid, or not, you will need a ‘wet and dry bulb’ thermometer. Then you look up the results on a ‘Relative Humidity Table’ (Appendix ‘C’, page 170, “A Simple Guide To Understanding Jet Engines”).
Mason's Psychrometer (Wet & Dry Bulb Thermometer)

RH (Relative Humidity) Table
Or a cold drink.
If you take a wonderfully cold drink of fresh, pure water that is slightly alkaline and, therefore, very good for you, pop a couple of ice cubes in it and sit the glass on the table. You will notice that there is condensation on the side of the glass. Or not.
In Yemen, where it is very, very humid, you will observe water running off the glass and then off the table rather in the manner that a tap will release water.
In Malaysia where it is less humid you will get a steady drip… drip… of water.
In West Africa where the air coming off the Sahara Desert is extremely dry there will be no condensation because the water is immediately evaporated off into the dry air. It will also be very dry in Antarctica but there the whole drink will turn to ice in a flash so it is hard to tell.
‘Do It Yourself’ humidity kit!

Another little thing is that irritating pressure problem we were talking about at the start.
The higher you go the less the air pressure around you is. Why? Because gravity is pulling the air down towards the surface of the Earth. The higher you go the less air is sitting above you to push down. Less weight above you—less pounds per square inch (in old money and I’m very old!).
Air Pressure (at International Standard Atmosphere) v. Altitude
Just recently I was flying back from Mauritania in West Africa to my home in Malaysia via Paris. At CDG (Charles de Gaulle) airport there was a change of aeroplane from the Airbus A330 of Air France to an Airbus A380 of SQ (Singapore Airlines).
The A380 cruised, eventually, at 40,000’ above sea level. That is high. Very high.
Just as we approached Singapore I put my plastic bottle of water on the armrest. The bottle was almost empty but I left a little to drink before disembarking.
When the aircraft sank to just below 10,000’ I took a photo of it.
Plastic Water Bottle After 30,000'+ Descent

Just goes to show what a difference 31,000’+ makes and remember—the pressure difference outside will be much greater, this is cabin pressure only.


Just a few things to think about when we say, “Just going out for a breath of fresh air…”

Saturday, January 9, 2016

Aerotoxic Syndrome


Firstly, my apologies for, perhaps, a lengthy ‘Blog’ this time. You will see why.

A question has winged its way over to me that set me back a little bit.
“Have you heard,” they asked, “about aerotoxic syndrome?”
The short answer to that is, “No. I have not.”
Sadly, easy questions tend to have difficult answers and so I need to go into a little detail here to sort this out for you.
The first thought was, ‘Is this another conspiracy theory that has been blown up out of all proportion?’
Some research seems in order here.

Sixteen years ago (1999) a group of chaps filed a report called ‘Aerotoxic Syndrome: Adverse health effects following exposure to jet oil mist during commercial flights’.
As a precursor to this, let us just review how the air gets into the cabin.
Ambient air—the air that surrounds the aeroplane in flight, is pushed into the engines because of forward speed. This is called ‘ram effect’. It is a good thing because the air is pre-pressurised before it gets to the compressor; it also makes the air ‘thicker’ for the fan to grip and push back.
Sorry

Once the air gets into the compressor the air pressure is raised some more to make it suitable for combustion where we shall add energy to the air by burning fuel in it.
Now back up just a little bit.
When the air is passing through the compressor there are off takes of air called ‘parasitic bleeds’ that are used for several functions on the engine and the flight computer and also a large amount goes off to the air conditioning unit(s) on the aeroplane.
This is the bit the air comes from

The amount of air passing from the air conditioning machine into the cabin is controlled. Too much bleed from the engine and fuel burn increases because we should need more ‘throttle’ to increase the airflow into the engine.
Remember that the primary need for air into the engine is for burning (for thrust) and for cooling the engine. Providing air for the passengers is, in reality, a necessary evil as far as the engines are concerned—remember the term ‘parasitic air bleeds’?
For this reason most of the air in the passenger cabin is re-circulated with only a percentage (about 50%) being replaced on a continuous basis.
How is it replaced? By making sure that the flow into the cabin is greater than the flow being released from the cabin. This will, in turn, raise the pressure of the air in the cabin to an acceptable level for human survival.
Sorry again

Survival? At 36,000’ there is not really sufficient air for a human being to survive. You would pass out in seconds and die in minutes from lack of air and cold.


So that is how the air gets there.
What about this ‘oil mist’ situation?
The oil that is used in jet engines is not dug out of the ground. It is synthetic. It is born in a factory. This is because mineral oil—oil that is dug out of the ground, is incapable of withstanding the temperature differences and pressures that exist in a turbine (jet) engine.
Note: When you see advertisements for engine oils for your car it will show you how great it is, in a CGI perhaps, at protecting the engine with the pistons going up and down and flames bursting around the cylinder.
Wonderful.
What is really needed is for the oil to protect your engine when it is not running; which is most of the time in your car. If the coating of oil runs off your car engine parts will rust. This is a bad thing.

Synthetic oil is thin to start with. When it gets hot it becomes even less viscous (it gets thinner). Keeping it where it is supposed to be is difficult.
Fortunately, those clever people at Rolls-Royce, for example, are very good at designing seals and sealing systems that will keep the oil where it is supposed to be.
But engines wear. Not much but over a period of time it can become significant.
To have an engine overhauled is expensive. Very expensive. We are talking in terms of millions of US dollars per engine.
Clearly the airlines will want to maximise the use of every engine before it gets sent back to the manufacturers, or an overhaul facility, for maintenance and servicing.

Because the air is tapped off from the compressor, the only sealing part of the engine that we need to worry about for the passengers is the bit at the front. This is called the ‘cold end’ of the engine.
The oil is re-circulated around the engine all the time while it is running. There are places where it gets really hot and the oil will partially break down. This is called a ‘pyrolised’ condition—a chemical alteration in the oil. The toxicity appears to be confined to the additives in the oil and the decomposition of the oil itself.
One of the primary checks the maintenance staff carry out every time the aeroplane is on the ground is to make sure there is no oil leak from the front of the engine—the nose cone and the fan cowl.
If oil is seen here then the engine comes off. No discussion necessary.

What is the likelihood of oil coming from the engine into the cabin? About 1% of the time. The possibility of the oil becoming hazardous is considerably less because stringent checks are carried out between each flight to prevent this from happening.
How do we know if there is a fume hazard in the cabin? Only the crew’s capacity to detect it is available at present. There are no detectors installed that might spot it—or other contaminants in the air.

Perhaps there is another cause for this aerotoxic condition that has not been looked at?
When the aircraft is at 36,000’ the air, in theory, should be relatively clear although certain gases are found at high altitude as a result of pollution. It is likely that these gases are a very small percentage of the total and so it is better to look at the flight envelope through the lower altitudes where industrial pollution is to be much higher.

Climbing out of, or entering, the Beijing area, for example, is likely to introduce toxic chemicals into the cabin because the incidence of industrial pollutants is much higher than in many other places. Beijing is not alone in having a pollutant rich air zone.

What are the symptoms?
            Fatigue – feeling exhausted, even after sleep
            Blurred or tunnel vision
            Shaking and tremors
            Loss of balance and vertigo
            Seizures
            Loss of consciousness
            Memory impairment
            Headache
            Tinnitus
            Light-headedness, dizziness
            Confusion / cognitive problems
            Feeling intoxicated
            Nausea
            Diarrhoea
            Vomiting
            Coughs
            Breathing difficulties (shortness of breath)
            Tightness in chest
            Respiratory failure requiring oxygen
            Increased heart rate and palpitations
    Irritation of eyes, nose and upper airways.
Can we cure it? Given rest and recuperation time your body should recover but repeated flights under these conditions can lead to considerable neurological stress that may become chronic.

Are all aircraft susceptible to engine oil bleeding into the compressor? Early BAe 146’s and Boeing 757’s are poor but the new Boeing 787 is exempt because the cabin air systems do not get their air from the engines. It has a separate electrically driven system for air conditioning and pressurisation.

“Should I worry?” you might ask.
According to the CAA (Civil Aviation Authority) in the UK there are about 30 pilots grounded by the CAA’s Medical Department because of a ‘suggested association between illnesses and the cabin environment’.
But remember that these are people who are sitting in this environment all their professional lives.
Passengers will consume far less time in the air and thus the risk is proportionately smaller.
There is no point in wearing a mask, it will not help. Even the ‘drop-down masks’ on the aeroplane will not help. The only answer is to get off.

At 36,000’ that could be a problem!





Monday, August 10, 2015

B-24 Liberator

I understand that this is not 'Jet engines' but, to an aviation person it is still interesting.

This is the forerunner of how this is mostly done today but with a greater emphasis on safety.

Watch and enjoy, then sit back and wonder at how this was achieved in 1941.

This was 6 months BEFORE Pearl Harbor! Henry Ford was
determined that he could mass produce bombers just as he
had done with cars, so he built the Willow Run assembly
plant in Michigan and proved it. It was the world's largest
building under one roof at the time.

This film will absolutely blow you away - one B-24 every 55 
minutes, and Ford had their own pilots to test them!!

ADOLF HITLER HAD NO IDEA THE U.S. WAS CAPABLE
OF THIS KIND OF THING.

https://www.youtube.com/embed/iKlt6rNciTo?rel=0

Saturday, August 1, 2015

MH370: July 2015


And so we move along. Slowly, it is true, but move on is what we do.

It seems that wreckage from an aeroplane has been discovered on the island of Reunion, a small island between the small island of Mauritius and the bigger island of Madagascar – or Malagasy Republic (whatever they choose to call it now!).
Along with the piece of aeroplane, it has been reported and photographed, there has also been found the wreckage of an anonymous piece of luggage that could have come from anywhere.
We may safely ignore the luggage even if it is emotionally rewarding to associate it with the loss of an aeroplane.
The part that is potentially worth looking at is the piece of the aircraft. This is something whose identity can be established.

Firstly, what is it?
That is simple enough. It is a ‘flaperon’. What, you may ask, is a ‘flaperon’. 
This is a small piece of the trailing edge of the mainplane, usually towards the inner portion of the wing. A flaperon is a type of aircraft control surface that combines aspects of both flaps and ailerons. In addition to controlling the roll or bank of an aircraft, as do conventional ailerons, both flaperons can be lowered together to function similarly to a dedicated set of flaps.

flightclub.jalopnik.com
As you will observe from the photographs, the part that has been found is quite large and quite substantial.
The Guardian

zenithair.com

Where has it come from?
The type and size match that fitted to a Boeing 777. It has yet to be confirmed that this is the case but it looks fairly certain that it is from that particular type of aircraft.
Point of fact: there have been no other Boeing 777’s lost in this area than MH370
If it is definitely proven that this flaperon came from a B-777 then, inevitably, the result must be that this is part of MH370.
Sad.

Why so far from the search site?
Ocean currents are strong and relatively fast. The aircraft went missing over a year ago. That this part showed up at all is miraculous and shows that there must have been, at least, some air inside it to keep it buoyant enough to float so far. It has floated for some time because there are barnacles on it.

Is it feasible that this part could have come from the search area?
Absolutely.
i.guim.co.uk
This illustration shows how far pieces could reasonably be expected to go given (statistically normal) condition in the southern reaches of the Indian Ocean.
http://edition.cnn.com/2015/07/30/world/mh370-debris-investigation/

What should we learn from this?
Well, we should learn that waiting for the results of an investigation is always a good plan. Rearing up and prancing around with a conspiracy theory, no matter how exciting it is, is always counterproductive.
As I have mentioned previously, in another ‘Blog’, it is inevitable that as soon as an aircraft crashes under mysterious circumstances everyone suddenly becomes an aviation expert. Conspiracy theories are always more attractive than truth.

Do we know what happened now?
No. We do not. But we are a step closer. 
One step at a time; step slowly, step positively; step carefully.


It may not be exciting but it is more satisfying to know the truth.