Between the Foot and the Rudder

When man took to the skies, he was certain about one thing: The efforts you put into flying, determine how well you fly. The relentless Wright brothers got it right, and then everyone followed suite.

Looking at it from a different angle, more from an operational perspective, for aircraft such as the Beechcraft King Air C90, the logic still applies. With metallic cables linking the controls with the control surfaces, the effort the poor pilot applies totally determines how the metallic bird flies.

Now, the C90 is a twin engine turboprop aircraft, member of the Beechcraft King Air family of popular and widely sold turboprop aircraft from Beechcraft (now part of Raytheon). “The Beech King Air is the world's most popular turboprop aircraft” [1]

But least popular with the girls, when an engine fails.

PA who flies the C90 talked of her experience with these marvelous C90s; And when one engine fails, humor breaks loose.

For an aircraft with two engines at a distance from each other, the failure of one creates an unbalanced torque that tends to yaw the aircraft. To compensate for this, the pilot must use the rudder pedals to create a countering torque: His or her foot on the pedal forcing the rudder to deflect towards the side of the engine which is still alive. And now is when you must remember, “The efforts you put into flying, determine how well you fly”.

The description of the scene was hilarious: PA was given a “single engine” scenario on the C90, by her instructor. The aircraft started to yaw, and she did as she was instructed: to kick on the correct rudder pedal. She kicked, but it didn’t move enough. And desperate times call for desperate measures: PA had to use her whole body weight on one single rudder pedal! “The rudder was very hard, and so I had to literally stand on the rudder pedal”. The thought of a pilot standing and flying is, well, hilariously imaginable.

But with technology, things these days get very “sunny”. Imagine, if for a small aircraft weighing 4500kgs, a pilot has to throw his/her whole body weight to achieve straight flight, what would anyone do for an Airbus A380 weighing 560,000 kg, in case of an engine failure?

The A380 is a 4 engine aircraft, and “basically even if both engines fail on one side u still DO NOT have to kick the rudder”, says Capt SK who flies the A380 for Singapore Airlines. No, he is not re-writing the books of physics.

“The TAC (which he thankfully expanded for me: Thrust Asymmetry Compensator) is part of the rudder which automatically compensates for an Engine Out (EO) or any form of thrust symmetry”. Computers on board the Airbus calculate the compensation required for a level flight, and feed it via 5000psi hydraulic lines to the upper portion of the rudder, a.k.a, TAC.

Some engineers out there may raise their eyebrows. “5000psi of pressure?”

Adds Capt SK, “Almost ALL electro-hydraulics tried out on this bird are completely new in the world of aviation......too many firsts. Firstly we have all hydraulic systems working on 5000 psi instead of the usual 3000 psi”.

All Airbus aircraft except for the A300 and A310 (both are no longer in production) use fly-by-wire technology (FBW). In an FBW aircraft, a pilot’s controls send electrical signals to computers which determine how much pressure needs to be pumped to the control surfaces. Aircraft manufacturers may decide to induce some artificial feedback to the control column (such as what Boeing does on its 777 FBW), or may have no feedback at all (such as on the sticks of Airbus FBW aircraft).

With technology, “The efforts you put into flying (or the lack of it), determine how well you fly”.

Gone are the days of the (w)right fliers!

TFE

[1] http://www.pilotfriend.com/aircraft%20performance/Beech/King%20Air.htm

Images:

Beechcraft King Air C90 : Copyright Dean Cully, from Airliners.net

A380 Image : Copyright Wim Callaert, from Airliners.net

Smoking Russian Beauties

If you thought this has anything to do with long legged Russian models, well, you're partly right.

On Saturday (March the 20th), I was making my way past a road that goes close to the threshold of Runway 09, Bangalore HAL airport (the old one, ICAO : VOBG). Under the brilliance of the midday sun, the silence of endless fields surrounding the old airport was broken by a sudden, harsh yet pleasing drone. A black nosed, grey bodied Antonov An-32 zoomed overhead, with its gear down, coming in for a landing. Suddenly, the "clean" aircraft let out thick black smoke from its engines, leveled off, and executed a missed approach. It quickly transitioned to a clean configuration, reducing itself to a small speck in the emptiness of the vast cloudless sky, its presence marked by the thick black smoke that speaks so well of Ukranian design. It was truly a sight to behold.

Very often the Indian Air Force (IAF) conducts practice flights at this airport. And when they do, life around the dull airport transforms beyond imagination.

Few months back, as I was riding parallel to the runway of the same airport, in the direction of the setting sun, golden rays from a majestic sun played hide and seek between the trees on the Old Airport Road, and when these rays failed to hide, golden shafts of light would strike my face, making me sport my best smile!

As I enjoyed this game with the sun and trees, from nowhere came the loud drone of a Russian engine…..and before long, an IAF AN-32, in all its glory, performed a low pass over the runway with its chin lights on: retractable landing lights that add to the beauty of the beast.

And, it didn’t pass without its usual thick black smoke.

The Antonov AN-32 is one long-main landing gear (long leg) Russian Aircraft, which entered service with the IAF in 1984. Now 26 years into service, these handsome beasts are in a class of their own: Majestic, yet coughing for both efficiency and performance. And my editor, who is a retired Air Marshall, used to fly them for the IAF, which happens to be the launch customer of this aircraft.

Says Vovick Karnozov, whom I had the pleasure of meeting personally at India Aviation 2010 (held at Hyderbad),

“Outwardly, the An-32 closely resembles a previous Antonov design, the An-26, from which it had been derived. The major visible difference is two king-sized Ivchenko AI-20D Series 5 engines, each 5180 hp, in lieu of the far more compact 2550-hp AI-24s. The An-26's fuselage, undercarriage and wing were beefed up to sustain higher loads and speeds. Having similar cargo cabin dimensions (inner volume 60 cu.m), the original An-32 featured higher gross weight (27t against 24t for the An-26), higher cruise speed (470-530 against 420-440km/h) and better climb performance (8000 m vs 6000 m in 19 minutes), while showing almost the same range with full tanks (some 2300 km). The An-26 itself had been derived from the An-24RV 48-seat passenger turboprop operational since 1969.

Unlike many other airplanes of the Soviet era, the An-32 was designed primarily for export, most notably for India whose air armed forces had a requirement for a light air lifter able to operate from short, hot-and-high aerodromes in the mountain areas (ambient temperatures up to 55 degree Celsius, airfield height above sea level to 4500 m). Such an airplane was of a little interest to the Soviet air force, which had opted for another Antonov design, the An-72 (first flight in 1977, in production since 1985) as its primary lightweight short takeoff and landing (STOL) transport.”

Adds Vovick, “Except for (I believe he meant to say “Apart from”) the outstanding thrust-to-weight ratio and well-tried airframe, the An-32 has a considerable price advantage over competing western designs, with flyaway price of $6-9 million (depending on version) against $12-20 million for the competition.”

When I shared this small yet sweet smoky experience of mine with Capt PR, who flies the 737 NGs with Jet Airways, and used to fly the Ilyushin IL-38’s for the Indian Navy, he himself had something interesting to share.

“Long back, landing into Mumbai on my ILYUSHIN which has a similar black profile, another aircraft waiting for takeoff had asked “What fuel do you use?”

We said, “coal!””

TFE

(BTW, when I editied my post, I realized that the original post had been created at 7:37:00pm. Can you see the Boeing aircraft in this time?)

Image Copyrights :

Top Left : Antonov AN-32, taken by Sushank Gupta

Bottom Right : IL-38, taken by Sergey Krivchikov

Both images from Airliners net

Birth in Aviation

Here goes my first ever blog, and it ought to start with those wonderful men and women who make aviation a flying dream.

Probably none of these ever helpful people would like their names to be published so openly here, so The Flying Engineer will be a guardian representative for each and every one of them. Here they are, in no particular order except the randomness of my mind:




1. Capt. AR : Airbus A330 / A320 / ATR-72 Captain
2. Capt. SK : Airbus A380/ B777/ B737NG
3. Capt. PC : Airbus A320 Captain
4. Capt. HSD : Airbus A320 Captain
5. Capt. DSD : Airbus A320 F/O, Embraer
6. Capt. RM : Boeing 737NG Captain
7. Capt. HK : Dassault Falcon 2000 F/O
8. Capt. RSR : Dassult Falcon 7x Captain
9. AT : ATR72-500 trainee F/O
10. PA : Beechcraft Kingair C-90A, TB-20
11. SJ : FMS developer, Airbus Family of FMS (A320/A340/A380/A350) with a major North American Avionics manufacturer
12. JH : manufactures 2 seater microlights
13. SR : Boeing 737 and ATR-72 AME
14. SY : Boeing 737 and ATR-72 AME
15. MEL : Boeing 757 AME
13: Myself (TFE) : Design Engineer with a North American Avionics Manufacturer, Aviation Journalist, Static Model collector, passionate instructor.

Although the tilt appears to be on Airbus, none of our opinions will be biased. After all, wings don't know who they're flying : an Airbus or a Boeing, or other?

Know that more than anything, this blog is for YOU, by me, of YOU. To every passionate individual out here, know that the dream to fly is fulfilled by the thrust to lift off the ground.

TFE