Question to all aviation experts: Fly/land w/o ASI?

[paulopp]

Greetings,


it's hard to believe, but there were occasions when state-of-the-art jetliners crashed after loss of airspeed indicators and/or altimeters (Birgenair 301/Aeroperu 603).

Now, I remember reading an article in Flightsim about handling the Curtiss Jenny in FS9, which indeed was equipped with no airspeed indicator at all!

The logic runs as this: Attitude controls airspeed.

The Jenny had no trim as well. At a given engine output the pilot could/must tell the current airspeed by the elongation of the elevators, and that means by the constant backforce he had to apply to the stick.

So, the question is, if commercial pilots confronted with a total loss of airspeed indication, could overcome their hazardous situation by falling back to the aforementioned basic piloting rule, and even manage to safely land their plane. In other words: were those accidents - other than watching, that pitot tubes and static ports were operational in the first place - preventable?


Kind regards,
Christian

[walterleo]

Hi friends:

There were accidents, where airspeed indication in modern jetliners were erronous at least temporary (AF 447) or contradictory Birgenair 310), all primary flight instruments were out as the static ports were by oversight still closed (Aero Pero 603).
The best advice on that is "Stick and Rudder" by Wolfgang Langwiesche written 1944: He (testpilot of the Corsair, the Cessnas etc) states that the angle of attac is the most basic indicator for safe airspeed it should be on board of all aircraft and directly visible to the pilots. As the AoA indicator not depends on the static ports it would work even with the ASI out of service. It also is not influenced by configuration changes, as long as the AoA is 6 deg up (more or less) all is well. E.G. in a Tu-154M 6 deg while clean could mean an airspeed of 550 km/h or 270 km/h in landing configuration.
Western aviation galantly went over Langwiesches wisdom and even in modern systems the angle of attac is measured but only as part of a computerized safety system which has its dark corners were indications are not clear (AF 447) or not arriving as planed ( Spanair 5022).
When AEROFLOT bought the 737-NTs they demanded to integrate an AoA indictator in its cockpits, as 40 years ago every Russian built airliner had.

For practical flying a small airplane without AoA indicator "attitude and power" is the rule and with experience one knows the values for every configuration. If not: reduce the power at a long final for a leishurly 700 ft/min descent and dont lower the flaps always keep the runway in sight at the lower border of the front window, at shortest final chop the power and raise the nose a little and wait for the chirp of the tires. The glider pilots do that in a similar way.

Kind regards

Walter

P.S.: I was two times at take off without an airspeed indication (a wasp had built her home in the pitot tube) both times thanks to checking the rise of airspeed after advancing the throttles I aborted in time my take off run in a C 150. So it was a non event. The most dangerous came afterward: The angry wasp.

[aerofoto - HJG Admin]

I was two times at take off without an airspeed indication (a wasp had built her home in the pitot tube)both times thanks to checking the rise of airspeed after advancing the throttles I aborted in time my take off run in a C 150. So it was a non event. The most dangerous came afterward: The angry wasp.

Given the sudden and unanticipated rush of air and assumed destruction of its habitat .... I too (like the wasp/bee) would probably be somewhat "pissed-off/angry" about the resulting blow-job and demolition of my new home too

Mark C
BOG/CO

[christrott]

Sept 1, 2016 11:55:18 GMT walterleo said:

When AEROFLOT bought the 737-NTs they demanded to integrate an AoA indictator in its cockpits, as 40 years ago every Russian built airliner had.

Are you speaking of the 737-400 order or the 737-800 order? If you are speaking of the 737-800 order, the NGs have always had an AoA display in the upper right of the PFD. The 737-400 had a similar indication available in the EADI, or could have a mechanical one installed. Several US operators had the AoA gauge installed on their aircraft. In fact, in Boeing's Aero Magazine Issue 12, Boeing talks about the AoA indicator, the PLI indicator, and other features already available on its aircraft. Also, the HGS (installed on many classics and NGs) has an AoA display available.


Anyway, to the initial question - any pilot properly trained in IFR flight SHOULD be able to fly and land an aircraft without the Airspeed indicator working. The problem comes with recognition of the failure, something many airlines and countries don't properly require training for or actually complete training for. AF447 is a perfect example where the crew had only been trained to recognize and handle pitot tube icing in very specific conditions near the airport. They had never been trained in a way that was appropriate for other phases of flight. As a result, when they attempted to resolve the failure, they followed the training they'd been given - which was wrong for that situation. This is the fallacy of training in many countries with regards to "Techincally Advanced Aircraft" (aka Glass cockpits). They train that the computer will recognize and announce any failures properly and that there is only a very limited number of ways to deal with these failures. If the failure isn't listed in the manual, they're clueless because they've not received the proper full training. This is why the FAA requires specific training for Glass cockpit aircraft separate of standard "steam gauge" planes. You have to learn where the glass cockpit can fail WORSE than the steam gauge aircraft and how to properly deal with it and make sure you can still fly by the limited standby instruments. It's not perfect, but it's part of the fundamental training regime for all pilots in TAA aircraft no matter when they start flying them, so it maximizes the time a pilot is exposed to these failures and understands in depth how failures occur and how to deal with them as a pilot (not a system manager).

[walterleo]

Hi Chris:

Regarding AF B 737s I have my information from the Project Tupolev forum where one of its founders ("DENOKAN") is check captain for the 737s.

Regarding AF 447 you are right it was primary a question of training or lack of it. But as in similar other cases it can be argued that the presence of an AoA indicator can help in such mind boggling situations. Nevertheless also Tu-154Ms were flown into flat-spins disregarding the AoA.
The conclusios for Pulkovo flight 612 read:
The cause of the crash was the aircraft being flown in manual flight mode with excessive angles of attack causing a stall with a subsequent transition to a flat spin and collision with the ground at high vertical speed. The Flight Manual and crew training programs did not provide instruction on manual pitch control and pitch trim during high altitude flight. The lack of appropriate simulators contributed to the crew’s lack of ability. While avoiding areas of thunderstorms and turbulence, the crew allowed the aircraft to enter pitch oscillations exceeding the angle of attack operational range. Lack of control over speed and not following the Flight Manual to prevent and recover from a stall and poor crew resource management allowed the situation to escalate into a catastrophic one.[4]

Sounds similar to the comments on AF 447.

But still more disturbing the events of Birgenair 301. A captain with 25000 flightours on nearly everthing the airline industrie developed could not avoid to stall his 757-200 while ON AUTOPILOT lured into that by false warnings of overspeed together with stick shaker actuation, and hindered to lower the nose manualy by the AP´s false trimming.

Kind regards

Walter

P.S.: The Crew of AF 447 had all the time reliable speed indications in front of them as the readout of GPS measured ground speed is always visible at the PF screens of the AB 330.

[christrott]

While I don't wish to sound derogatory of a well respected member of the community, I have to disagree with his statement whether it be about the B737-400 or B737-800 order. As I linked to above, Boeing had the AoA indicator available on the 737NGs, 777s, and 767-400s, and was promoting its use in 2000; nearly a decade before the Aeroflot NG order. Additionally, the 737-400 had the AoA indicator available back in the 1980s not long after the BMI crash in Manchester. Aeroflot wouldn't order the 737-400 until 1995(ish). I looked at pictures of the ex-737-400s and unless later operators removed them, there is no separate AoA gauge on those aircraft. Any AoA indication would have been on the EADI, something that again had been available for almost a decade prior to Aeroflot.

AF447 was "reversion to training". Something that happens with lower-time pilots. They followed their training despite contradictory indications because they froze up. Same thing happened with the Colgan Air DASH-8 a few years back (although that was due to fatigue more than low time).

The thing that pissed me off about AF447 more than anything (I've gotten over the whole "Cruise Pilot" certification BS. Nothing is going to get EASA to dump that pile of garbage) is that Airbus had the ability to have the AoA displayed on the screens of ALL Airbus aircraft but refused to do so or allow customers to do so until after AF447. United, Northwest, and Frontier had all been asking for YEARS for such indication (as all operated Boeing and/or Douglas products which had AoA indication), but Airbus refused. Then suddenly after AF447 Airbus was like "oh yeah, here's the procedure to turn on the AoA indicator." That's infuriating and unacceptable, but again, they're not held to task because the politics of having the European Governments so directly invested in EADS means they don't have any effective way of doing so.

[walterleo]

Hi: didnt say, the 737s have a Tu-154 style AoA indicator glued to the glareshield. It is in the PFD, if this was decided before or after the Aeroflot order is not of big importance, what is important, that the AoA indication is available INDEPENDENTLY of a row of computer calculations crying "STALL" if you lower the nose and get silent again if you pull the sidestick, as happened in AF 447.

Kind regards

Walter

Regarding Airbus and AoA inducators:

AB 300 and 310 had them, Concord had them even the Caravelle 12 had one. Why from 320 onwards it was originaly not presented seems more of a question of overreliance on computer-systems and French "RAISON". Maybe also because training pilots costs the airlines more than leasing the new marvel.

[walterleo]

Hi Chris:

In your link there is the reference of an option of an AoA indicator on the PFD of the 737. I was talking about that option in my post and Aeroflot has selected this option. I dont see any point where we two disagree.
The other measures to integrate AoA into the PFD as on the speed tape are sideways via the computerprogrames. As the vanes for measuring the AoA are present on all modern airliners, the question is only how to present the datas to the pilots.

And it seems that many airlines still dont select the option of presenting directly we are talking about:

www.pmflight.co.uk/wp-content/uploads/2014/08/737mainpaneldetail.jpg

Kind regards

Walter

[paulopp]

Hello everybody,

thanks Walter and Chris for your comments, very much appreciated! I take from them that it is not only possible to fly and land a plane safely with proper AoA instrumentation and crew training, but it is/should be actually a prudent safety requirement to be prepared for these circumstances.

It would appear that the discussed incidents were occasions after which lessons could/should be learned with regard to AoA-flying.

Best regards,
Christian

[christrott]

Sept 3, 2016 9:09:55 GMT walterleo said:

And it seems that many airlines still dont select the option of presenting directly we are talking about:

www.pmflight.co.uk/wp-content/uploads/2014/08/737mainpaneldetail.jpg

TBH, all the 737NGs I've been on had the AoA turned on. Its activation/deactivation only requires a maintenance function done with the FMGC in the maintenance mode (similar to how you can do it with the PMDG NGX and 777). Oddly, I've not seen a single panel graphic with it shown (like the one you show above). Don't know what the reason for that is.