Airbus has released a very crisp video of the sharklet’s developmental timeline. For a detailed insight into the program, please click on the following link: http://theflyingengineer.com/flightdeck/winglets-and-sharklets/
Airbus has released a very crisp video of the sharklet’s developmental timeline. For a detailed insight into the program, please click on the following link: http://theflyingengineer.com/flightdeck/winglets-and-sharklets/
Capt Saleem Zaheer, Chief Pilot – Flight Operations at Indigo Airlines, sent out a mail to all Indigo flight crew describing his flight experience of the first flight of the A320 equipped sharklet, VT-IFH. Capt Saleem, and his senior first officer, flew the aircraft on the DEL-MAA-CJB-DEL pattern (Delhi – Chennai – Coimbatore-Delhi).
In course of their flight, the flight crew noticed no difference between the handling qualities of the sharklet-equipped A320, and their fleet of non-sharklet equipped A320s. The crew however noted the movement of ailerons and outboard spoilers when flying through turbulence, which is in accordance with a design by Airbus known as the Load Alleviation Function (LAF). The higher bending loads experienced by an A320 wing equipped with Sharklets, especially under conditions of rapidly fluctuating lift (when flying through turbulence), need to be alleviated. To accomplish this, the outboard spoilers (Numbers 4 & 5 on both wings) and the wing ailerons are deflected in accordance with the fall or rise in life.
VT-IFI landed in Delhi yesterday, and is the second Sharklet equipped A320 to join Indigo’s fleet.
Below is a video of VT-IFI’s first flight ever, which was on the 25th of January, 2013, at Hamburg, Germany.
Air Asia recently received the world’s first “Sharklet”-equipped A320 for commercial operations. Indigo and Go air will very soon have VT-IFH and VT-GOL flying in the Indian skies; both equipped with “sharklets”. Ever wanted to know more about these “Sharklets” that are grabbing headlines today?
Here is a comprehensive article on Winglets, or what Airbus prefers to call them: “Sharklets”, which are “Hunting down fuel burn“.
Read more by CLICKING HERE.
My flight on the 20th of December 2009 was a memorable experience. My friend, who was a first officer with the then 5 star airline, Kingfisher, had informed the captain (an ex-IAF officer) and the lady first officer that I was their passenger on their Delhi – Bangalore flight. Comfortably seated on 37A, I found the orange juice stain I had left behind on the same seat when flying from Bangalore to Delhi a couple of days earlier.
Having been part of a huge “makeover” program at Honeywell, I was keen to gather flight data that I could possibly use for my training at the company. I sent out the “In flight form” to the crew members, scribbled on sheets from the hotel where the company had accommodated me. Most of the data is, as you will notice, from the FMS pages of the Airbus A320 family.
VT-KFY, the Airbus A321, was the first, and till date, the only A321 that I have flown on. Branded with MSN 3302, and fitted with IAE V2500 engines, I was all too interested in the then 2 year old airplane.
With the DGCA Cancelling the license of Kingfisher Airlines, this article is a tribute to an airline whose employees and flights taught me so much.
Flight Plan & Navigation
VT-KFY, operating as IT-207 was planned to fly Delhi to Bangalore via airway W20S and W57S. W20S starts from the VOR at Delhi (DPN), and runs south-south east till Hyderabad International Airport’s VOR, HIA. W57S starts at HIA, and terminates at Bangalore International Airport’s VOR, BIA.
Our take off was from Runway 28, which is westerly in its orientation. After take off, the aircraft has to join the airway, for which the Air Traffic System at busy airports provide what are known as a SIDs: (standard instrument departure), which are laid down procedures that specify how an airplane taking off from a particular runway may intercept and join a particular airway. In our case, the then effective AKELA 3B SID was applicable, which details how the airplane, after takeoff from Runway 28, may turn left to intercept waypoint AKELA, which lies on W20S.
Airspace restrictions make W20S head south-south-west till waypoint KALNA, before changing direction to south-south-east towards Bhopal. This non-direct route between the two radio stations at Delhi and Bhopal makes an airplane fly 15NM extra. However, in practice, pilots request for a direct-to from AKELA to BPL, which, more often than not, is granted, saving around 10NM of ground distance. Upto waypoint IBANI, the aircraft flies in the Delhi Flight Information Region (FIR). Passing IBANI, the aircraft enters Mumbai FlR.
Mumbai is around 420NM from waypoint IBANI, and yet, the airplane must be in contact with Mumbai Control, which is physically located at Mumbai. Communication link between the airplane and the centre, through direct VHF will not be possible, as a VHF radio’s range is limited to line of sight: around 200NM. Overcoming this problem are VHF transmitters positioned in the Mumbai FIR such that when a voice transmission over VHF occurs at Mumbai, the same VHF signal is broadcasted from multiple ground transmitters. This ensures sufficient coverage throughout a FIR.
From BPL, pilots are often granted a direct-to all the way to waypoint VABDI, which saves hardly anything.
Since the route is easterly, even though slightly, ICAO specified RVSM cruising levels have to be adhered to. Airplanes flying easterly, must fly at “Odd” flight levels (FL). Example, FL 290, FL 310, FL 330, and so on. FL 290 stands for Flight Level 290, which is 29,000ft above sea level at an assumed barometric pressure of 1013.25hPa (hector Pascal) at sea level. Since it is an “assumption” that is followed by every airplane at the flight levels, all airplanes with their altimeters displaying 29,000ft with the assumption set in the altimeter, are flying at the same altitude, through the true altitude may differ by as much as 2000ft from the displayed altitude at this “Standard Barometric” pressure of 1013.25 hPa.
About 20NM from waypoint BUSBO, the aircraft is “released” from Mumbai control and “handed over” to Chennai Control, where pilots may contact the physical centre at Chennai (approximately 400NM away from BUSBO) on one of 11 VHF frequencies.
Observing the route, the direction changes toward the west (south south west) over waypoint VABDI. However, back then, when Chennai did not have sufficient radar coverage, airplanes on W57S needed to either climb 1000ft or descend 1000ft over Hyderabad. This was to change the cruise altitude from an ODD flight level to an EVEN flight level earlier than VABDI, for surveillance reasons. As far as our flight was concerned, we descended from our cruise level of FL 350 to FL 340 over Hyderabad.
We approached Bangalore from the north east, and the active runway at that time was 09, which is east facing. We were “vectored” (given compass headings to follow) by air traffic control, and “broke off” from W57S in a divergent heading. This was to take us further west, before directing us to intercept the ILS for runway 09.
The airway distance between Delhi and Bangalore is 950NM. However, with the standard instrument departure and the arrival into the airfield, the total ground distance increases to 980NM, which is an extra of 30NM. With the soon to be introduced RNP route between Delhi and Bangalore, this sector’s ground distance shall reduce significantly.
VT-KFY, for that day’s flight to Bangalore, weighed 79 tonnes, as against its all up weight of 89 tonnes. 14.5 Tonnes of fuel was uplifted, and the centre of gravity was determined at 24.7% of the Mean Aero Dynamic Chord (MAC). Permissible range is 15% to 35%, with a preference for a rear CG to improve fuel burn performance. Corresponding to this CG, the horizontal stabilizer was trimmed for nose UP to an Airbus defined position of 1 unit. This is to keep stick forces (on the pitch axis) almost neutral during takeoff.
A quick look at the Flight Crew Operating Manual for the A321 reveals that for a 980NM flight at FL350 (assumption: no winds, wind data on that day wasn’t collected), the A321 with a takeoff weight of 79 Tonnes burns approximately 6600kg of fuel for the entire flight from takeoff to landing. Approximately 200kg is burnt during startup and taxi, raising the estimated fuel burn to 6800kg. The estimated flight time between take off and landing is 2 hours 22 minutes.
The difference between the uplifted fuel (14,500kg) and the trip fuel (6800kg) was huge: 7,700kg. Bangalore’s ATF rates being higher than Delhi’s, 7.7T of fuel was “tankered” to Bangalore, which was to be used up for the next day’s flight to Delhi out of Bangalore.
A Cost Index of 18 was used for the flight. The Cost Index is a measure of the cost of time v/s the cost of fuel. The unspecified unit is kg/min, which in this case translates to 18kg of fuel being as costly as 1 minute of flight time. If the cost of fuel was low, the cost of time relatively goes up, which increases the numerical value of the cost index. If the cost of fuel goes up, the cost of time in comparison pales, lowering the numerical value of CI. Last year, most flights by Kingfisher were operated at around Cost Index 10. Lower the cost index, slower the airplane flies. For our flight that day, CI 18 corresponded to a cruise speed of Mach 0.775 under no wind conditions. There must not have been any significant winds, as the aircraft’s FMS targeted the same Mach number for cruise.
Takeoff was planned with “Flap configuration” 1+F, which is the first of four selectable “configurations” on all in-production Airbus commercial airplanes. 1+F corresponds to 18° of slats and 10° of flaps on the A321. Lower flap settings provide better fuel burn and climb performance.
Because the airplane was taking off 10 tonnes lighter than its maximum, full engine thrust for take off wasn’t required. Although the outside air temperature that night was 15°, the engine was told to produce a thrust corresponding to an outside air temperature of 44°C. Specifying a higher temperature reduces the generated thrust, saving engine life through reduced operation at the extremes. The thrust was “flex(ed) to” 44°.
With this thrust setting, the specifics of Runway 28 at Delhi, weather and the weight of the airplane, the aircraft’s take off speeds were determined as V1 : 152kts, VR : 152kts, and V2 : 156kts. V1 is the decision speed. If anything was to have happened that demanded the take off to be rejected, the decision to reject must have been made before the airplane reached the decision speed of 152kts. Attempting to stop the airplane beyond this speed is unwise, as the combination of aircraft energy and remaining runway length will prevent the airplane from stopping before the end of the runway. Vr is when the pilot pulls back on the stick to “rotate” the nose up into the air. V2 is the takeoff climb speed: the speed that is maintained on the initial climb out phase (when gaining altitude is important) before building up further speed.
Delhi’s airport is at an elevation of 777ft MSL. Takeoff thrust and take off speed (usually V2 + 10, 166kts in this case) was maintained till 1000ft above ground level, or 1720ft above MSL. At that point, the thrust was lowered to climb thrust, and the nose pitched down to maintain the same speed (V2 + 10), till 1500ft above airport elevation, or 2277ft in this case. Passing this altitude, the nose was further lowered, to build up airspeed. As the airspeed built, the flaps were retracted to “clean up” the aircraft, allowing for further acceleration. The best lift to drag speed is realised at the “O” speed, which was 217kts on that day for the given aircraft weight.
The Cruise Altitude of FL350 was determined by looking for the optimal cruise altitude at the aircraft’s weight and weather conditions. Least fuel burn is expected at the cruise altitude. Since the aircraft was flying east, the ODD flight level closest to the optimum altitude is chosen, which, in our case, was 350.
For the A321, the time to this cruise altitude, under ideal conditions at 79 tonnes, takes 25 minutes over 160 NM , burning 2000kg of fuel. Air Traffic Restrictions normally prevent most airplanes climbing out of Delhi from reaching their cruise altitude this early.
Reaching cruise, the aircraft became lighter by 2 tonnes, reducing its weight to 77 tonnes. At this weight, at FL350 under ideal conditions, the airplane guzzles around 2800kg of fuel per hour, at Mach 0.78 (450kts ground speed). Considering that the aircraft needs at minimum around 100NM to descend, and 160NM to climb, 720NM at best is traversed at cruise. This implies approximately 1hr 30 minutes in cruise, burning 3,200kg of fuel.
Starting descent, VT-KFY might have been around 73,800kg heavy. Interestingly, a light airplane descends faster. Descent from FL350 at continuous IDLE thrust takes about 17 minutes over 100NM by an A321, under ideal conditions, at the specified weight.
Our A321, for landing, was configured with full FLAPS, which corresponds to a slats of 27° and flaps of 25°. The approach speed, at the estimated landing weight of 73,000 tonnes, was 142kts. Kingfihser later adopted CONFIG 3 landings, which extends slats / flaps to 22°/21°, offering lower drag and saving fuel.
The autobrakes were set to Low (LO), one of three positions: LO, MED, HIGH. No Thrust reversers were used for landing, which was, and still is part of fuel saving procedures the world over.
The ATR 72-500 has its idiosyncrasies. In the cockpit is a “seat position sight gauge”, which are three small, coloured balls that allow a pilot to adjust his viewpoint to a position that ATR deems appropriate, allowing for a “correct view of instrument panels as well as runway environment”. The photo above shows the ATR 72 cockpit, with the sight gauge enlarged in the inset. If the first officer is to have his viewpoint right, he must adjust his seat height and position such that when looking at the three balls, the left white ball is obscured by the red centre ball.
Interestingly, this gauge is not found in the Boeings, where the recommended method of adjusting the viewpoint is different. The ATR 72-500/600’s competitor, the Q400, however, has something similar, called the “eye level indicator”, as may be seen in the second photo. The Airbuses, not surprisingly, have a sight gauge similar to that found on the ATR.
Possibly one of the smartest first officers in India told me, after seeing me so diligently adjusting my P1 seat in an ATR 72-212A (500) to the correct viewpoint, that I was too high. Apparently, the seat position sight gauge does do its job well, but it isn’t something you’d want to level your eye with on an airplane like the ATR 72-500. Why? Visual perspective.
With the eyes adjusted, the view is good, and clean. But with the ATR 72, (and the Q400) one has to be very careful with the flare: the airplane’s fuselage is long and low, and a tail strike is easy. Another complication is the aircraft itself: having a constant speed propeller means that when you pull back on the power levers, the pitch angle of the propeller blades changes to “fine” (almost perpendicular to the direction of the airplane’s travel through the air), resulting in a significant increase in drag. If the flare is more than required, and the airplane balloons*, pulling back on the power levers is the last thing one would want to do, as the drag would make the aircraft drop to the runway like a stone! So one would add power to keep the airplane up, and this will eat up more runway: Messy indeed. And for him, with the ATR recommended viewpoint, comes the tendency to flare more than required.
*[The term “balloon” refers to a landing airplane that rises slightly before touching down. Ballooning is typically caused by excessive airspeed or excessive back pressure being applied to the flight controls by the pilot during the landing flare]
So what he does is to sit lower than the recommended view point: low enough to make him actually look up to see outside. This works well for him, and few others who have settled for this more comfortable, though not recommended, seating technique. Anything that works!
What can go wrong just because of an improper flare?
On 9th May, 2004, N438AT, an ATR 72-212, during the approach to landing, the captain stated to the first officer (flying), “you better keep that nose down or get some power up because you’re gonna balloon.”. After the airplane crossed the runway threshold, the captain stated, “power in a little bit, don’t pull the nose up, don’t pull the nose up.” The captain then stated, “you’re ballooning,”. The airplane touched down with a vertical load of 1.3G, bounced into the air, touched down a second time, then bounced into the air with a nose up of 9°, climbed to 37 feet, and touched down a third time with a vertical load of 5Gs. After a fourth touchdown, the badly damaged airplane came to a stop outside the runway.
On 17th September, 2005, D-ANFH, an ATR 72-212A, Just prior to touchdown, the co-pilot pitched the aircraft nose up to an attitude of 6.5º. The aircraft landed hard on the runway and bounced; in the course of the initial touchdown, the lower rear fuselage struck the runway surface.
On 23rd May 2006, G-BWDA, an ATR 72-202, towards the conclusion of a brilliant approach, the first officer closed the power levers at 10ft and flared the aircraft. The airplane touched down, bounced into the air, and the attempt to arrest the sinking of the aircraft to the ground, pulled back on the control column, striking the tail.
And yes, I have also heard some of my friends say, “Oh damn, I forgot to flare!”
[787 production video at the end of article]
The 21st 787 to be delivered, and the first of 27 Dreamliners destined for Air India, VT-ANH was delivered yesterday to the ailing national flag carrier in a low key ceremony at Boeing’s South Carolina delivery centre. Scheduled to be ferried to Delhi today (Friday, 07 September 2012), the dreamliner is expected to touch down at Indira Gandhi International Airport (IATA: DEL, ICAO: VIDP) on the morning of Saturday, 08 September 2012.
The Dream-liner has actually been quite a nightmare for Air India. A four year production delay, and the antics of the Indian Government, and “pure-blood” Air India pilots, have made things quite distasteful. Air India pilots not wanting pre-merger Indian Airlines’ pilots to get rated on the 787, The Indian government (through Air India) demanding greater compensation from Boeing, and the 28th July un-contained GEnX-1B engine failure during high speed taxi trials on a 787 destined for Air India have culminated in making the 787 appear (literally) like an blood smeared dagger responsible for an aviation bloodbath.
VT-ANH is Line number 35, and the manufacturer’s serial number 36276; its first flight having been conducted on the 25th of January, 2012. Of the other 787s produced / in production, VT-AND (Line 29) and VT-ANI (Line 46) are ready for delivery, while VT-ANA/B/C/E/G are in storage and undergoing rework. VT-ANJ (line 54) and VT-ANK (Line 60) are undergoing pre-flight preparations, while line numbers 65 and 72 (unregistered) are undergoing final assembly. Line Number 90, to be assembled in Everett, is also destined for Air India.
Rework is underway on the earlier line numbers (25, 26, 28,30, 32), possibly to fix the 10 – 15% reduced range (6900NM as against the promised 7700 – 8200NM) due to the 8% overweight airplane.
How does this airplane compare to the existing twin engine widebodies flying for Air India?
All technical information have been sourced from Airbus and Boeing published documents
AATD, Aviation, aviation flight, Bangalore, BATD, Bendix King, Cessna 172, flight simulator, Flying Training, G1000, general aviation, Honeywell, India, Instrument Flying, KAP 140, Practice, Recency, transportation
A 5 month sabbatical from my website (I continued to write for my print magazine, Airbuz) was well spent. I engaged myself in the design and development of a General Aviation Flight Simulator. Either click HERE to know more, or visit my section, “Projects”.
I must thank my readers who were both patient and concerned. I hope you like the simulator!
And yes, I’m back!
0.89, 381kts, A320, A380, Airbus, Airbus A380, Authority, Dive Speed, Expedite Descent, Flight Test, High, HSP, Mach, MD, MMO, Overspeed, Proection, Sidestick, SPeed, Structural Damage, VD, VD/MD, VMO, Warning
An apparently “lesser known” fact about the Airbus A320 is the dive speed, its significance, and the associated consequences.
The dive speed is the absolute maximum speed above which the aircraft must not fly. Typically, to achieve this speed, the aircraft must enter a dive (steep descent), as the engines cannot produce sufficient thrust to overcome aerodynamic drag in level flight. At the dive speed, excessive aircraft vibrations develop which put the aircraft structural integrity at stake.
On the Airbus fly by wire aircraft, it is not possible to reach the dive speed, due to the flight envelope protections available in normal law. If the sidestick is maintained full forward, and the airspeed crosses VMO/MMO, the pitch nose-down authority smoothly reduces to zero at approximately VMO +16 / MMO + 0.04. This however, does not guarantee the airspeed stabilizing at this speed.
If MMO + 0.04 / VMO + 20kts is reached or exceeded, then a structural inspection is necessary. Beyond MD (= MMO+0.07) / VD (= VMO + 31kts) (A320 family), structural disintegration can occur.
Here are the speeds for the A320, in Mach number and Kts. The lesser value must always be respected, at all times:
MD/VD = M0.89/381kts
Maximum Operating Speeds:
MMO/VMO = M0.82/350kts.
Expedite Descent (as on FCU, if available)
The graphical representation of speeds above VMO/MMO, on the left (made by The Flying Engineer), gives you a clearer picture of the speeds, their significance for the FBW system, and the consequences.
To understand the seriousness of the VD/MD, take a look at the video below, which involves the VD/MD testing of the Airbus A380. The MD for the A380 is Mach 0.96, and the test crew dread taking the airplane that far.