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As I already explained in a reply to another post higher up, two sensors is not fine if they are of the same type. Several airbus airplanes suffered a violent pitch down because both AOA probes iced up at the same time while going through a layer of icing conditions, resulting in a stall detection at higher altitude. One of these events is described here.

The correct action is to crosscheck AOA with other airplane data to make sure it's consistent. Which is a few lines of computer code since all the hardware already feeds into those computers. Airbus has implemented this fix, and Boeing will now do the same. Belatedly.

GP's post is very relevant. This is indeed something that is taught to every student pilot: never rely on any single instrument, always crosscheck. It's unforgiveable that they didn't program it this way, especially after the Airbus incidents.

No, it was AOA probes. You're thinking about AF 447 which was a pitot problem.

Here's a description of one of the events.

Extract from the Boeing 737-200 Pilot Training Manual February 1982 page 04.80.31. Edited for brevity

Runaway and Manual Stabiliser - Recovery from Severe Out-of-Trim

"In an extreme nose-up out-of-trim condition, requiring almost full forward control column, decelerate, extend the flaps and/or reduce thrust to a minimum practical setting consistent with flight conditions until elevator control is established. Do not decrease airspeed below the minimum maneuvering speed for the flap configuration. A bank of 30 degrees or more will relieve some force on the control column. This, combined with flap extension and reduced speed should permit easier manual trimming.

If other methods fail to relieve the elevator load and control column force, use the "roller coaster" technique. If nose-up trim is required, raise the nose well above the horizon with elevator control. Then slowly relax the control column pressure and manually trim nose-up. Allow the nose to drop below the horizon while trimming. Repeat this sequence until the airplane is trim.

It is unclear if the Ethiopian pilots were aware of this procedure, but given that they were close to the ground and at too high of a speed to deploy flaps, the yo-yo maneuver would not have been feasible.

[citation, please]

http://www.pprune.org/rumours-...

There is an extensive thread about this on the Professional Pilot rumour network and they favour Hypoxia

what movie did you get that from?

You get to my age, some things in movies are almost as real as what really happened :)

However, this discussion on PPRuNe suggests that I didn't make it up. Several professional pilots are on there saying that it's their normal practice. Before anyone points it out, I can see that the thread is ten years old, and it may very well be that modern CVRs aren't using 30 minute magnetic tape loops.

Spray some more: http://www.pprune.org/rumours-news/518971-ethiopean-787-fire-heathrow-11.html#post7939225

There's a suggestion on AvHerald and PPRUNE that the problem was caused by a coffee heater in the galley; probably boiled dry, and the safety circuit failed.

from http://www.pprune.org/rumours-news/518568-asiana-flight-crash-san-francisco-4.html#post7925947
"I went into SFO r28L last week, no glide slope, and no papis visual approach only and the DME doesn't read 0dme at the threshols!

Very easy to undershoot or overshoot without vertical guidance! Espesecially as this crew probably hadn't done a visual approach for a long time! "

Also: aeronav.faa.gov/content/aeronav/acfstatus/Presentations/13-01_AAUP_Approach_Status.pdf

> If it was an engine going out, then they could have just
> shut it down and flew home on the remaining engine

It's not so simple at takeoff and landing, any time you are below or near low speeds and at low altitudes things get very very complicated.

http://dx.doi.org/10.1109/AERO.2000.878212
http://www.pprune.org/archive/index.php/t-58841.html

In summary - in theory you can always save the day. In reality -- one mistake, and you're going down hard.

http://www.pprune.org/dg-p-reporting-points/467610-merged-qantas-grounded-effective-immediately-4.html MERGED: Qantas grounded effective immediately. - Page 4 - PPRuNe Forums www.pprune.org *At 6 pm the federal government said it was making an urgent application to Fair Work Australia to order an immediate cessation of industrial action

According to the AC in this comment, the Twin Otter use cable controls, not hydraulics. The Wikipedia page doesn't seem to address this, but this discussion, seems to prove the AC wrong. The commenter here says the standard aviation hydraulic fluid (MIL-H-5606) has a pour point of below -75F and that Canadian operators Kenn Borek Air had no reported problems at -68C. However, this Wiki article says that MIL-H-5606 is only usable to -65F / -54C. There's another fluid called MIL-H-87257 developed for fire resistance without compromising low-temperature capability, but it seems to have the same -54C limit.

You also completely ignored the aerodynamic issue with coils on the wings and the lack of runway.

Right, I was only addressing the hydraulics issue. However, it does seem like the Twin Otter is capable of the trip, and has been used for exactly this purpose before. I wonder how they dealt with the frozen fuel and grease issues.

The consensus on the PPRuNe forum is that this amounts to a discovery process.

The sub-thread starts on this page.

There are some long and technical discussions of the flight leading to no more conclusions than we've seen out of the BEA. A thorough reading, however, gives you some appreciation for the problems BEA is facing given the paucity of information that is available. There are two threads if you go looking. One got too long and was retired. It contains some interesting weather data I've not seen elsewhere.

{^_^}

"<I am nearly as fast on EFD as on paper>"

This can be true but a language doesn't design a bad system, a software engineer does. Many reliable systems have been built using Java and reside in hospitals, transportation, and power infrastructure. I can't blame a language or runtime for piss poor design. Also keep in mind not all Java applications or runtimes are the same.

Searching for more on this issue I found a post on how ATC insiders view it on the PPrune forums (UK site for professional pilots): http://www.pprune.org/atc-issues/427001-efd-scottish.html

Kind of an interesting behind the scenes look.

From what I can tell via google,

- Ash melts at 1100 degrees, below operating temperature of jet engines, and fuses into the engine
- Windshields can be abraded so badly you cannot see out of them
- Ash is dry and doesn't show up on radar, so new sensors are needed so pilots can discover it
- There are no standards for how much ash is allowed or how to test aircraft against it.
- Possibility that propellor planes and helicopters are safer

So my conclusions for now are:
- Need better rules, and government should pay for the experimentation
- Need better intelligence, so we can be sure a route is safe
- Need to examine flying propellor planes slowly at very low altitudes below the ash
- Nobody has thought about ash bothering ground transportation. Does it?
- Need alternative transportation
    o Trains, buses, boats
    o Slower aircraft.. hovercraft or balloons? (they still have engines though)
    o Need a closed engine design. (chemical or hydrogen powered electric closed engine?)
    o This is a common problem, more needs to be done for global transportation security. I even found a volcanic explosion in Japan yesterday at the ash advisory center, though it is not in the news at all.
http://ds.data.jma.go.jp/svd/vaac/data/TextData/20100420_SAKU_0403_Text.html

Links:
http://www.pprune.org/rumours-news/412103-ash-clouds-threaten-air-traffic.html
http://www.guardian.co.uk/science/2010/apr/15/volcanic-ash-bad-for-planes
http://www.boards.ie/vbulletin/showthread.php?threadid=2055888944
http://www.ssd.noaa.gov/VAAC/vaac.html

The worst part about this law? Personal electronics in the cockpits of small planes make then safer when used for flight-related purposes, and using personal electronics for purposes unrelated to flying is already against the rules, so this law can't possibly do anything but cause harm. I can't tell you how many stories I've heard about:

• pilots using cell phones/PDAs to check weather.com or wunderground.com or whatever so they can actually see the weather system
• pilots using cell phones to talk to the tower after a radio failure
• pilots using laptops for various flight operations calculations or to more rapidly search the operator manuals for an esoteric problem or...

Might as well provide a link to professional pilot discussion on the subject. To sum up the thread, they mostly think our Congress are a bunch of morons. Usually if the people you are regulating think you are utterly incompetent, that's a clear sign that you should take a step back, pull your head out of your backside, and rethink your position.

Sadly, Congress in their infinite ineptitude, will almost certainly blaze ahead and pass this law, thus dooming some flight a few years from now that could have been saved with personal electronics in the cockpit. And, of course, they'll never know that the flight could have been saved because they aren't smart enough to recognize the hundreds of times this has already happened.

I think we need a constitutional "cooling off period" amendment that says that with the exception of laws to provide financial relief, no law may be passed in response to any accident, catastrophe, or other incident, whether of natural or human cause, for a minimum of one year (or even two) after the incident in question. Such a law would have prevented so many of Congress's worst screw-ups. Hmm. I think I've said this before.

There are 3 teams racing to break this record. The Brits, the Aussies and a USA/Canada team.

Yes, they are heated. Here is a brochure: Thales Airbus sensors and probes.

"Or was this an error of the heating system, or what?"

I don't know the answer, and I don't find anyone claiming to know. I'm guessing that there is a subtle design error. If I could hold a Thales pitot in my hand I might be qualified to theorize why it fails. But I would not be qualified to design a better one, although maybe I could help do the design.

Apparently there are no problems with the Goodrich pitot sensors. (PDF file)

I've been studying how the world deals with issues such as this one. There are cover-ups as money is spent to influence and confuse the media. But now there is a huge difference from 20 years ago. Now the pilots, who don't want to lose their lives, have a voice. There are numerous blogs with many interesting comments. For example, now the media is being fed the apparent lie that the problems with the pitot sensors are new. But someone posted this TFU [technical follow-up], showing a report from December of 1995: TFU 34.13.00.005. Here is someone asking a question about that: Question: The problem was known since 1995. Why such long time for correcting the default?

None of the authors of articles for news agencies seem to have any technical knowledge. In the past it didn't matter, since the rich didn't want you to know. In the past people had to accept whatever the news media said.

Since the Thales sensors are being replaced, the smart thing would be to get one that has just been removed and examine it.

Interest some:

http://www.pprune.org/rumours-news/375937-air-france-a330-200-missing-21.html#post4967832

"Quote:
It would be very easy to add external device with internal GPS that can send aircraft position every 5 minutes or so over its own satellite uplink.
Ironically, the aircraft in question, which like most modern jet airliners was fitted with ADS-B, would have been squittering its position, altitude, groundspeed and ROC/ROD at half-second intervals continuously during the flight on 1090MHz..."

"Almag" has some interesting things to point out, too... (in that same forum)...

The story was on the news long enough to seem authentic but then went quiet. Maybe both sides worried about appearing ridiculous?

Googling found this page of related stories (including rock grenades) https://www.pprune.org/military-aircrew/86382-tornadoes-drop-concrete-bombs.html and yes, it appears both the RAF and USAF used concrete bombs and they were actually laser-guided, not just dumb.

Some useful information about the aircraft (not verified by me - taken from http://www.pprune.org/forums/showthread.php?t=309337):

Initial Report AAIB Ref: EW/C2008/01/01 Accident

Aircraft Type and Registration: Boeing 777-236, G-YMMM
No & Type of Engines: 2 Rolls-Royce RB211 Trent 895-17 turbofan engines
Year of Manufacture: 2001
Date & Time: 17 January 2008 at 1243 hrs
Location: Undershoot RWY 27L, London Heathrow Airport
Type of Flight: Commercial Air Transport (passenger)
Persons on Board: Crew - 16
Passengers - 136
Injuries: Crew - 4 (minor)
Passengers - 1 (serious)
Passengers - 8 (minor)
Nature of Damage: Substantial
Information Source: AAIB Field Investigation

'Rumour' has it that the F-111G have already been decommissioned quietly http://www.pprune.org/forums/showthread.php?t=295292

I am not a professional pilot, but I frequent aviation boards and most everyone (except the accountants) are against this training. Just imagine an incapacited captain in a 747, with this co-pilot only trained in a sim having to do a no visibility, one engine out go around in a bad african airport. Long thread but worth reading for those interested at http://www.pprune.org/forums/showthread.php?t=2441 14

Some speculation would indicate that there may have been problems with the oxygen supply to the two pilots.

If this was inoperative, then they may well have passed out whilst trying to figure out what was wrong or even trying to get to a secondary source [e.g. portable bottles held in the cabin].

There was an incident on board an aircraft in 1989 over the English Channel [I've lost the link to the official report]. The aircraft cabin altitude rose; the captain passed out; the first officer took control; the flight attendant on seeing the captain lying on the floor tried to help and passed out as well. The first officer managed to carry out an emergency descent to lower altitude and all survived. It took 4 mins to descend from the flight level (35,000ft+ I recall) down to some 12,000 feet as you cannot just throw the plane into a dive - it has to be controlled to avoid overspeed etc.

The reason for the depressurisation ? - which wasn't explosive but was fast enough - a fatigue crack hidden behind a door seal.

For those who keep saying "this isn't a big deal," or complaining about how infeasible this is, perhaps it would help to read about what actual pilots think?

Professional Pilots Rumour Network: Professional Laser injures Delta pilot's eye thread.

A user of the service on the flight was posting to the Professional Pilot Rumour Network PPRUNE www.pprune.com , the thread is here.

Can't tell if anyone's linked this yet, but there are some interesting comments at PPrune on what level of training these nuts would have needed (sorry, frames site - no direct link).

The popular media seem to have made up their mind that it's evil technology again. Maybe some of the victims could sue M$ on this basis.