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airman1900
20th Jan 2011, 12:21
From Wall Street Journal, Jan. 20, 2011 page B4:

Two Planes Grounded After Tail Strikes
By ANDY PASZTOR (http://online.wsj.com/search/term.html?KEYWORDS=ANDY+PASZTOR&bylinesearch=true)
A recent spate of safety lapses by American Airlines, including a Boeing 757 that apparently took off at an unusually slow speed and slammed its tail on a California runway last week, are prompting concerns among federal safety officials as well as some of the carrier's pilots and mechanics.

None of the incidents resulted in injuries, though two planes suffered enough damage to warrant temporarily taking them out of service. An airline spokeswoman said "we take each incident very seriously," various internal reviews are under way to understand the causes, and American usually works together with labor and government officials "to make sure these types of incidents are mitigated."
She didn't provide details of what precipitated the operational problems.
Federal officials are conducting their own investigations into a number of incidents ranging from last week's takeoff error at Los Angeles International Airport to a botched landing in late December that resulted in a jet carrying 181 people running off the end of a snowy Jackson Hole, Wyo., runway.
The takeoff mistake in Los Angeles ended with the Hawaii-bound Boeing 757—piloted by a senior-management captain who is the chief pilot for 757 crews based in Los Angeles—quickly returning to the field. The aircraft may have suffered significant damage from what is called a "tail strike," which usually happens when the takeoff angle is too steep and the rear portion of a departing jet's underbelly hits or drags on the runway.
The heavily loaded Boeing 757 was taken out of service and may need repairs to its rear bulkhead, according to people familiar with the details.
The plane was ferried to American's Tulsa, Okla., maintenance base earlier this week, without passengers and under rules requiring the pilots to fly at lower altitudes in order to reduce structural stresses from pressurizing the fuselage.
A Federal Aviation Administration spokesman said the agency is investigating the Los Angeles tail strike and safety experts are "assessing the extent of the damage to the bulkhead." The National Transportation Safety Board also has looked into the incident. Tail strikes occur from time to time, mostly on longer models such as Airbus A340 or Boeing 767 and 777 jets, but safety experts said they are particularly unusual during takeoffs of 757 jets.
Greg Smith, the management captain who was in command of the flight, didn't respond to questions, and the American spokeswoman said employees aren't authorized to speak to reporters.
In the past few weeks, the AMR (http://online.wsj.com/public/quotes/main.html?type=djn&symbol=AMR) Corp. unit also experienced a separate tail strike at Los Angeles Airport involving a Boeing 737 taking off for Canada. American said it didn't tell U.S. or Canadian investigators about the event because the damage wasn't significant enough to warrant such reports. The plane, however, remains out of service, pending a decision slated for next week by American's engineering and maintenance experts. At a minimum, according to people familiar with the matter, the aluminum skin around the plane's tail was damaged.
In early January, yet another American jet, this time a Boeing 767 wide-body aircraft, had to return to New York's John F. Kennedy International Airport shortly after takeoff, when its nose gear wouldn't retract. After making a safe but overweight emergency landing, it turned out that mechanics had failed to remove a pin installed during overnight maintenance.
The New York incident has attracted attention from American pilots and mechanics because such pins have red-and-white streamers attached to them, reminding crews to "Remove Before Flight." None of the mechanics, baggage handlers or other ground staff noticed the pin prior to the plane's beginning its taxi for takeoff. The aircraft's pilots, who are responsible for visually checking the condition of every aircraft prior to flight, also missed the pin.
The American spokeswoman said the airline doesn't publicly "discuss corrective actions" affecting pilots.
At least three of American's recent incidents featured some unusual factors, and that's partly why they have sparked intense scrutiny from different groups.
The staff of the safety board, for example, appears especially interested in figuring out why the experienced captain in the Jackson Hole event failed to manually deploy panels on top of his jetliner's wings to help decelerate the speeding plane after touchdown. The panels failed to deploy automatically as the cockpit crew expected. Investigators are examining whether a maintenance mix-up contributed to that failure, and somehow also may have helped delay deployment of devices at the rear of the engines intended to slow the jet by reversing the direction of engine thrust.
Initially, the pilots of the Boeing 737 that scraped its tail climbing away from Los Angeles didn't realize anything unusual had happened. But during the flight, according to people familiar with the details, flight attendants alerted the cockpit crew that they had heard sounds of creaking metal after the jet's tail smacked the runway.
The Boeing 757 damaged during takeoff from Los Angeles may have been climbing at a speed of less than 120 miles an hour, according to people familiar with the details. That's markedly slower, these people said, than such a 110-ton jet typically would be flown in order to lift safely off the ground.
Write to Andy Pasztor at [email protected] ([email protected])
Copyright 2011 Dow Jones & Company, Inc. All Rights Reserved

Mercenary Pilot
20th Jan 2011, 13:03
piloted by a senior-management captain

Investigation over. :E

sevenstrokeroll
20th Jan 2011, 13:52
mercenary pilot... seems to know how things really are.

I would like to know if the rate of rotation was too quick on the hawaii bound plane.

but seriously...if the plane wasn't loaded as the weight and balance info (numbers) said, the trim setting may have been wrong for takeoff.

that bit about the nose gear pin is a bit disturbing though. we kept our pins onboard the plane , checked them on the walk around and counted them in the cockpit.

PEI_3721
20th Jan 2011, 13:55
I recall some Boeing data, several years ago, which showed a cyclic pattern to 757 tailstrikes. IIRC this was against fleet flight-hours which at that time equated roughly to a two and a half year period. Boeing were investigating reasons for this, some of which were that pilots progress through the industry, training programs evolved to match new priorities, and that humans (management, training and crews) forget the context or priority of safety initiatives.

I have seen and generated similar safety data which showed a cyclic pattern. Patterns probably can be found in any data, but with some circumstantial correlation from the items above, I wonder if there are any other safety patterns or studies which might help the safety of our industry.
The items all appear to be aspects of change, thus is the pattern a function of change management?

Sqwak7700
20th Jan 2011, 15:46
Investigation over.

So true. What's the saying - those who can't, manage? That is the biggest threat, a manager at the controls. :eek:

I would like to know if the rate of rotation was too quick on the hawaii bound plane.


I hate to quote journos, but it sounds like rotation at the wrong speed;

The Boeing 757 damaged during takeoff from Los Angeles may have been climbing at a speed of less than 120 miles an hour,

Again, this is coming from a journo. but a Hawaii bound 757, or even a lightly loaded one should not be climbing out at 120 (assume he means rotation?). Maybe this management genius mistook the V1 call and began rotating? I've seen it happen before with new pilots when they are nervous, which could happen to someone out of their element (ie, flying only enough to stay current.)

Anyway, tailstrikes on a 75 do seem quite rare. :confused:

411A
20th Jan 2011, 16:05
American Airlines...again.
It should be remembered that it was a 'senior management pilot' that crashed his MD-80 at Little Rock, trying to land in a thunderstorm.

Perhpas...management pilots need to stay firmly in the office, or...have a bit more regular line flying experience.:rolleyes:

aterpster
20th Jan 2011, 16:26
411A:

Perhpas...management pilots need to stay firmly in the office, or...have a bit more regular line flying experience.

Depends on what the management pilot does. If he gives line checks all the time he (she) is probably fine. If, however, he/she is a "chief pilot" office paper shuffler, then watch out.

At my airline the latter type usually were smart enough to assign a "F/O" to their occasional currency flight who was, in fact, a sharp check airman.

lomapaseo
20th Jan 2011, 17:37
I always interpreted a management pilot to be one who exhibits strong personality traits and opinions without the currency of flying the actual product.

Much like the opinions we often see posted on PPrune:E

stepwilk
20th Jan 2011, 17:45
Since I have never flown aircraft long and powerful enough to whack their tails, can somebody explain to me what causes tailstrikes?

Yes, I understand that overrotation "causes" the strike, but what leads to the overrotation? Simple carelessness? Pulling too hard/fast? Not paying attention to the proper pitch indication? Nervousness about too long a takeoff roll? It seems so simple that if 10 degrees is a proper rotation and 12 degrees will hit the tail, you don't let the little veebird go past 10.

Or am I missing something?

bearfoil
20th Jan 2011, 17:54
Lack of sufficient a/s, (Lift) to leave the ground. Once committed, one gets airborne, or plows ahead into the Autobahn, Beach, Snow bank. 100 knots probably not enough velocity, imo.

hetfield
20th Jan 2011, 18:54
These incidents/mistakes happen frequently.

In our airline we had a summary about it. To make it short, mostly it was due to wrong inputs in the FMS e.g. wrong weights, or wrong flap settings, or a combination of both.

gulfairs
20th Jan 2011, 19:05
When I was an apprentice pilot I recall being admonished for rotating to quickly in an L188c aircraft. fortunately that type of machine just got up and flew, but the admonishment stuck in my memory core right thru my career thru to the big heavies.
The growling I received from a long deceased crusty old Captain was
"When-you-rotate-you-will-count-to-three!"
I even used it when were were running out of cement at Gatwick, right on the last 500ft mark before the piano keys.

misd-agin
20th Jan 2011, 19:11
bbg - a better technique would be to use the 'NY decimal' system for your 'count'

That's a one...
That's a two...
That's a three...

By then the plane will have left the ground and the tail would be clear of the runway. :ok:

sevenstrokeroll
20th Jan 2011, 20:40
pei3721

re: cyclic: it all boils down to ''fundamentals''...you are never too good to practice the fundamentals in the sim.

I prefer the Lawrence Welk counting method to the NY method...ahoneannatwoo anna you know what to do

Airbubba
20th Jan 2011, 23:24
Tail strikes occur from time to time, mostly on longer models such as Airbus A340 or Boeing 767 and 777 jets, but safety experts said they are particularly unusual during takeoffs of 757 jets.

I'll have to agree with that statement. The 75 is not that light in pitch compared to other planes I've flown. Also, the tail clearance is fairly generous for a long aircraft.

A couple of the classic causes for takeoff tail strikes are setting the airspeed bugs wrong and trying too agressively to achieve the 'ideal' 2 degree per second pitch rate they harp about in the sim.

bubbers44
20th Jan 2011, 23:31
When you fly once a month as a management pilot you are at the same proficiency as a line pilot flying once a month. Striking a tail out of LAX with about 12,000 feet of runway would never happen with a line pilot. I don't care how mistrimmed it was if the W&B was off. I thought it was an SNA take off when I heard about the tail strike. But at LAX?

I had a friend that had his captain screw up and not set the flaps in a 737 out of LAX one day when maintenance pulled the takeoff warning circuit breaker to not hear that annoying sound about flaps everytime they advanced the thrust levers. They didn't get a tail scrape but did a stick shacker on lift off. My friend should have caught it too but he didn't. Unless I was flying out of SNA I let the airplane fly itself off the runway with proper pitch and not worry because I had 8,000 ft in front of me at rotation. I guess management guys know something we don't.

JammedStab
21st Jan 2011, 02:18
Since I have never flown aircraft long and powerful enough to whack their tails, can somebody explain to me what causes tailstrikes?

Yes, I understand that overrotation "causes" the strike, but what leads to the overrotation? Simple carelessness? Pulling too hard/fast? Not paying attention to the proper pitch indication? Nervousness about too long a takeoff roll? It seems so simple that if 10 degrees is a proper rotation and 12 degrees will hit the tail, you don't let the little veebird go past 10.

Or am I missing something?

It seems that frequently when someone in a large jet tries to takeoff erronously with the flaps up or with V-speeds much lower than they should be for their heavy weight, that they end up with a tailstrike. A good example is the 727 in Dallas many years back.

So here is my question. Why does the tail strike happen. I assume that these particular pilots know not to exceed a certain pitch angle. 10° nose-up on the 727 was about the max you wanted with the mains still on the ground.

So is it because the pilot flying rotates, does not lift off and then tries to force the aircraft in the air. I don't think that a pitch instability would be involved as the tail is probably flying fine. If I ever happen to encounter this situation on the 727 where I am at my 10° noseup attitude and not lifting off, aside from adjusting thrust, what do you recommend in terms of pitch. I might be tempted to lower the nose.

Just curious.

Gulfcapt
21st Jan 2011, 02:35
This is worse than a string of bad luck. Something isn't right at AA and they need to get to the bottom of it.

Best,
GC

bearfoil
21st Jan 2011, 02:57
I think China had a TS not too long ago, in a 340. At the end of the Runway, and with bugs missing a few legs, Captain had to get airborne or plow through the fence and into some buildings. He chose flight over certain death. 30-50 million dollars and possibly a Hull loss, he did what he had to do. Keep pulling until it gets off the ground. the alternative is to not raise (or even lower) the nose, and start virtually over. Reject the T/O when you cannot stop in time, or cost the Company an airplane, or at least a gazillion Euros, (Yuan). Live, and learn Bartending.

sevenstrokeroll
21st Jan 2011, 03:13
I seem to recall that the 727 has a tail skid (retractable)...so does the DC9 series, though it is called a bumper.

ok, a managment pilot bumped the tail...its the old line:

1 week away from flying and I FEEL IT
2 weeks away from flying and my copilot feels it
3 weeks away from flying and my passengers feel it
4 weeks away from flying and a tail strike happens.
5 weeks away from flying and they make me a chief pilot

PappyJ
21st Jan 2011, 04:14
Since I have never flown aircraft long and powerful enough to whack their tails, can somebody explain to me what causes tailstrikes?

In theory, any aircraft could suffer a tail-strike during Take-off or Landing (except taildraggers).

A tail-strike occurs when the horizontal stabilizer (Tail) is capable of generating a sufficient downward force that the lower tail section of the aircraft is brought into contact the ground before the aircraft is able to fly. Think about basic flight theory - angle of attack and stalling.

In other words, exceed the "Ground" angle of attack and a tail-strike occurs, just like the exceeding the "Air" angle of attack will cause a stall.

It generally happens when the aircraft is either rotated, or flared, at a speed below optimal for the conditions (Vr, Vref, etc) It can also happen if the pilot is aggressive on the controls (Over-rotation,etc), but in this case the tail-strike is caused by aircraft's geometry over reaction time, not really by the aerodynamics.

Some aircraft would appear more prone than others based on their design. The 727, some 737's, 767 and some others, have limited tail/runway clearance and subsequently were manufactured with a "Skid" which would offer at least some damage protection.

411A
21st Jan 2011, 04:16
This is worse than a string of bad luck. Something isn't right at AA and they need to get to the bottom of it.


Yup, but true to form at AA, they are in the deny/deny/deny mode.
Isn't going to change, either, unless the FAA suspends their operating certificate.

PappyJ
21st Jan 2011, 04:18
think China had a TS not too long ago, in a 340. At the end of the Runway, and with bugs missing a few legs, ... or cost the Company an airplane, or at least a gazillion Euros, (Yuan). Live, and learn Bartending.

I'm pretty sure that this was an Emirates A340 taking-off from Melbourne, Australia.

masalama
21st Jan 2011, 04:39
We had a tail strike at our outfit(737 NG) about a year back on takeoff accompanied with stick shaker as the copilot had made wrong takeoff speed calculation( max Reduced thrust) at max takeoff weight and the relatively new captain didn't notice the error in his haste to get going.

Luckily, other than structural damage and a few frightened pax , the aircraft made it OK. Both pilots were grounded for a while and after investigations and corrective training are now flying. A rule of thumb I use(taught to me by a senior check pilot) to cross-check the speeds is the V2 speed set in the MCP window should be approximately 20 knots less than takeoff weight ...eg. if T/O weight on the -800 is 70 tons ( 70-20=50) , therefore 150 knots approx. For the -700 , reduce by 25 .

masalama.

bigjames
21st Jan 2011, 04:58
the rule of thumb is a good idea however some of the recent tailstrikes have occured due to incorrect weight being entered in the first place... garbage in...

Halfnut
21st Jan 2011, 17:17
Captain Greg Smith is the LAX Director of Flight. Which makes him the big cheese for the base.

golfyankeesierra
21st Jan 2011, 22:20
Captain --- --- is the LAX Director of Flight
No reason to put his name on internet, is there?:= (Next time it's you!)
BTW, what is he called now?:}

Gulfcapt
22nd Jan 2011, 00:32
No reason to put his name on internet, is there?:= (Next time it's you!)
BTW, what is he called now?http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/badteeth.gif


His name was in post #1 which means it was also in the WSJ.

SKS777FLYER
22nd Jan 2011, 22:06
The 757 rotation technique as taught at AA is to smoothly begin rotation AT VR trying for 2.5 degrees per second to 10 degrees. The aircraft should be airborne during those 4 seconds and rotation is smoothly continued to maintain V2 +15 which requires 18-20 pitch attitude.
At VLO and 10 degrees pitch, the 757-200 tail (All AA 757's are -200s) is about 33 inches above the tarmac with the struts extended. Tail contact takes about 12.5 degrees with struts extended. With struts fully compressed, which they would NOT be for any TO the tail will contact at 10 degrees.

golfyankeesierra
22nd Jan 2011, 22:18
His name was in post #1 which means it was also in the WSJ
Sorry, thought they were only talking about "the chiefpilot". Later on in the article his name was indeed mentioned.

AirRabbit
22nd Jan 2011, 23:01
Tail strikes are not limited to takeoff situations – they occur during landings as well. As PappyJ very correctly states:
In other words, exceed the "Ground" angle of attack and a tail-strike occurs, just like the exceeding the "Air" angle of attack will cause a stall.
It generally happens when the aircraft is either rotated, or flared, at a speed below optimal for the conditions (Vr, Vref, etc) It can also happen if the pilot is aggressive on the controls (Over-rotation,etc)…

However, I don’t completely understand the balance of PappyJ’s comment …
in this case the tail-strike is caused by aircraft's geometry over reaction time, not really by the aerodynamics.
Any tail strike involves aerodynamics – the way the controls are manipulated to influence the aerodynamic characteristics of the airplane. For example, if the controls are moved abruptly, not giving the airplane a chance to be influenced by the changing airflow … like a continuing rotation on either takeoff or landing … and the airplane may well achieve a pitch attitude that would place the tail structure appetizingly close to any “airplane-eating runway” on the planet.

Certainly it can’t be the training at AA, as all airlines in the US are required to comply with the training that is contained in part 121 of the FARs … and that would include AA, right?

PJ2
22nd Jan 2011, 23:44
As a sidebar comment, I know of at least two airlines which provide the crew with flight data information right after takeoff and after landing. The speed, RA, pitch attitude, pitch rate (deg/sec) throughout the maneuver), Vertg, Descent Rate are all provided to the crew for their examination if they wish. Providing this information to the crew immediately, gives them something to learn from if a rotation or a flare was slightly outside normal. This use of flight data has already reduced tailstrikes at these two airlines. This data remains the crew's to use/dispose of as they deem.

Typical FOQA Programs have events which track how close an aircraft came to tailstrike on liftoff or on the flare at landing, as well as monitoring rotation rates, (almost all the events I've seen were very slow rotation rates...between 0.8 and 1.5deg/sec and took a long time to get the pitch to 15deg +).

Tailstrike on the approach is most certainly aerodynamic in nature - we have seen higher risk of tailstrike with a quartering tailwind and the airspeed right on the bug, (Vref +5 or Vapp on the 'bus). There is a FOQA event that monitors flare times as well; Any flare longer than 8 to 10 seconds can be an indication of higher risk of tailstrike and here is where aircraft geometry can come into play.

Both the FOQA events and the data link information to the crew are attempts to deal with the problem of tailstrikes and are obviously preventative. Of course, in any actual incident, all data is available to the airline safety investigation team and flight ops to see if there are training issues.

twochai
24th Jan 2011, 19:39
Perhaps...management pilots need to stay firmly in the office, or...have a bit more regular line flying experience.

Many years ago, demonstrating new aircraft to airline and military operators around the world, while trying to make the demonstratee look (and feel) good, we always used the maxim: "watch out for Chief Pilots and Colonels".

Scene 1: lined up on the departure runway, CP of a developing world airline in the left seat, very thorough briefing complete, T/O clearance received - Me "Any questions?" - He "Yes, which one's the airspeed indicator?"

Scene 2: CP of a legacy flag carrier in the left seat, CAVOK day, calm wind, very light weight, no issues. The result - the hardest landing I ever experienced in my career and, - it happened a flash!

Chief Pilots and Colonels! And then I were one.....

AirRabbit
26th Jan 2011, 18:35
Tailstrike on the approach is most certainly aerodynamic in nature - we have seen higher risk of tailstrike with a quartering tailwind and the airspeed right on the bug, (Vref +5 or Vapp on the 'bus). There is a FOQA event that monitors flare times as well; Any flare longer than 8 to 10 seconds can be an indication of higher risk of tailstrike and here is where aircraft geometry can come into play.

Both the FOQA events and the data link information to the crew are attempts to deal with the problem of tailstrikes and are obviously preventative. Of course, in any actual incident, all data is available to the airline safety investigation team and flight ops to see if there are training issues.

While “flair time” may be a decent data point for discussion, it seems to me that anyone who is still “flaring” any airplane (i.e., continuing to move the nose to a higher position) after anything approaching 8 to 10 seconds is indicative of the fact that the pilot has no idea of what attitude he/she wants for the airplane to land. Said differently, that pilot likely knows not what he/she is attempting to achieve, or if he/she is just pulling on the controls “until it lands” which would be a classic case of the airplane flying the pilot. To avoid speculation, the attitude that should be sought is the attitude that would achieve level flight for the airspeed and airplane configuration at THAT time. There should be no way that the level flight attitude of any airplane, particularly when in ground effect, would require such a nose high position that it would risk a tail strike. Pulling the nose up above the attitude that would maintain level flight is only inviting something that no one would desire. Transport category airplanes are not expected to be landed “in a full stall” condition. Unless someone flies final approach at something like 8 – 10 degrees nose LOW, there is almost zero chance that a change in airplane attitude (i.e., flare) should take anything approaching 8 to 10 seconds to achieve a level flight attitude. It would seem to me that any review of FOQA data that shows any pilot flaring for something approaching 8 to 10 seconds will have already demonstrated the need for additional training – tail strike or not.

bearfoil
26th Jan 2011, 19:39
So, "flair" is the culprit. Hunting (waiting) for liftoff after initiation (rotation) or T/D (landing) is not a stabilized approach. Rather simple. Is that it? Poor speed control?

sevenstrokeroll
26th Jan 2011, 19:42
I've worked for three small airlines and one really big airline. AT no time was their a discussion of "Flare" techniques or concepts.

It took seperate study on my part to learn the following:

1. Learn and be aware of the visual clues that can lead you to ''flaring'' too long. For example, when on a runway sloping downhill, if you ''keep flaring'' you will keep floating as the runway is moving away from you...

I was going to write an extended explanation, but have decided I enjoy talking about other people screwing up and if they actually learned something, the whole pprune thing would get dull.

stepwilk
26th Jan 2011, 19:50
Interesting. I had assumed that all tail strikes happen as a result of overrotation on takeoff. Never occurred to me that you could have one on landing.

bubbers44
26th Jan 2011, 20:08
Over rotating on take off is poor pilot technique because you did it to yourself with no outside forces. Landing and hitting the tail is poor pilot technique with outside forces. The pilot flying shouldn't be getting a tail strike unless he or she really screwed it up. I can see it happening after a bounce and screwing the recovery up but not a normal landing, no matter what the wind component is. When you fly to Hawaii once a month and get one or two landings anything can happen.

My biggest challenge was landing uphill on a short strip in Honduras in a 757 and landing in a climb. Firm landings were quite common there. It took a while to figure the climb angle needed to get a smooth touchdown.

stepwilk
26th Jan 2011, 20:22
That would be what we used to call Tegoose.

bubbers44
26th Jan 2011, 21:33
But wasn't it fun? Landing uphill at TGU rarely happened because of the prevailing wind so we got really good at landing north. Landing south seemed so easy, uphill, but our best landings were downhill turning final at about 100 ft to miss the hill. I really miss that place. Had a reverser not work one day but no big deal. I am waiting for the report to see how this could have affected one of our arrivals. The 757 is a wonderful airplane, lots of power and you can override everything manually. I like it as much as my beloved Lear Jets. It is hard to kill yourself in machines like that if you pay attention.

Halfnut
26th Jan 2011, 21:40
Rumor is the total damages (not including loss of revenue from being OTS) will come to $5 million USD.

BobM2
26th Jan 2011, 22:02
Over rotating on take off is poor pilot technique

Over rotating is not the problem. Rotating at too slow an airspeed is the culprit & there is not much margin on a long body aircraft. Most airline jets are normally rotated to 15+ degrees & most would drag ass if still on the ground at that attitude. The rotation speed is set high enough & rotation rate slow enough that liftoff will occur at <10 degrees & the a/c will climb sufficiantly for the tail to clear the ground at 15 degrees. But there's not much margin for error because the manufacturer wants the slowest Vr possible for the best runway performance. A rotation 5-7 knots slow may be all it takes.

sevenstrokeroll
26th Jan 2011, 22:27
it is possible, though quite rare, that if improperly loaded a normal rotation can suddenly turn quite bad ending in a tail strike. I am not suggesting that these two events in the thread are that situation.

for anyone who has not seen a ''tail strike'' may I suggest the following movie? "thirty seconds over tokyo" has a tail strike in it. Done intentionally in the first 30 minutes or so, it is also the source of the name of the author of the book of the same name. "The Ruptured Duck".

Except for the mushy parts, its a great movie.

Brian Abraham
27th Jan 2011, 01:23
Boeing article on tail strikes

Tail Strike Avoidance (http://www.boeing.com/commercial/aeromagazine/aero_04/textonly/tr01txt.html)

pattern_is_full
28th Jan 2011, 01:20
"Stepwilk: Since I have never flown aircraft long and powerful enough to whack their tails, can somebody explain to me what causes tailstrikes?"

Actually, if you are around small tricycle planes, especially those used for training or rental, take a look at their tail tiedowns. You will note that a lot of these have flattened bottoms, the result of inadvertently becoming tailskids multiple times through tailstrike incidents. In training they most commonly happen when practicing low-speed liftoffs into ground-effect (short or soft-field techniques).

So length and power don't necessarily have a lot to do with it. It is a question of either poor control technique, or correct technique applied at too low a speed.

Put simply, if the aircraft will suffer a tailstrike at, say, 12 degrees, then the rotation (even if perfectly executed) had better not take place until the speed (and thus lift) is sufficient to lift off at a lower angle of attack (say, 8 degrees).

While small planes usually rotate and lift off at "oh, about 65 knots," a specific Vr is calculated for every heavy-aircraft flight based on weight, air temp, etc. Either a poor calculation of Vr, or an error in setting that Vr on the airspeed gauge, may lead the pilot to rotate at too low a speed. Flying by the numbers only works if the numbers are right.

Dr. Bru
28th Jan 2011, 17:08
Good article by Boeing.

Shell Management
29th Jan 2011, 14:48
One has to question the effectiveness of AA's FOQA and ASAP programs.

bubbers44
29th Jan 2011, 23:50
I think any pilot hired by AA would know how to properly land an airplane before being hired. AA shouldn't have to train their pilots to land. Maybe the management pilots need to stay current and not just fly once a month. If they only fly once a month maybe they should watch a video of how to rotate on take off and land an airplane. Look at management pilots versus line pilots incidents and you will see what I am saying.

sevenstrokeroll
29th Jan 2011, 23:57
there is some wisdom in what bubbers 44 has to say. but not just management pilots...any decent pilot who hasn't flown in awhile (you fill in the blank here) needs to get back in the swing of things.

we've done automation to death...couple the lack of handflying with reliance upon automation and only flying once a month and you have problems headed your way.

the solution is simply this...management pilots should not be on any type of long haul flying...short legs with lots of takeoffs and landings will help keep them current. You don't need to practice sitting in cruise for 4 hours or so...that should come naturally.

bubbers44
30th Jan 2011, 00:27
The problem with the short flights is management doesn't want to do them. They want to do two legs a month to somewhere easy. That is how it has always worked in my company. The Hawaii flight was easy so made him current for the month. He just forgot how to rotate properly because he spent the last month in his office. How many of us have scraped their tails? None for me in 23,000 hrs. I am sure for you watching too.

bubbers44
30th Jan 2011, 00:44
7sr, I agree with what you say about management pilots flying short legs but they won't do it. They just want to fill the square as qualified pilot so make it as easy on themselves as they can. The ORD chief that overran Little Rock Airport is an exception.. He was doing the tough trips.

sevenstrokeroll
30th Jan 2011, 02:18
all the recent Bravo Sierra about min fuel, management pilots not doing short legs with more landings, and other things could be fixed by the simple expedient:

the FAA changes the fuel reserves to 75 minutes instead of 45 minutes (plus the other stuff) and make it 6 landings in 90 days instead of 3.

oh well.

mach92
31st Jan 2011, 22:31
I was on the AA 757 LAX HNL in First Class. The rotation did seem slower and steeper then normal up front. The F/A's in the back knew something had hit as everyone aft of the wings according to them could hear it. The Captain said little except we are returning to LAX. We landed 25R full fire rescue and taxied into the gate. The Captain said "we probably will be departing soon so everyone stay seated with this minor delay" I was laughing so hard. I told the guy next to me we are OTS no question. 5 minutes later a MX supervisor came on told the CS lady the plane has a big hole in it. :eek:

bubbers44
1st Feb 2011, 11:49
The fire/rescue was required because they were landing over max landing weight because the 757 has no fuel dump capability. If the captain thought initially they would be able to leave again shortly he had no knowledge of the damage done.

AirRabbit
1st Feb 2011, 16:00
So, "flair" is the culprit. Hunting (waiting) for liftoff after initiation (rotation) or T/D (landing) is not a stabilized approach. Rather simple. Is that it? Poor speed control?

Getting a tail strike on takeoff happens when one of two situations exist – 1) rotation is begun at an airspeed well below the proper rotation speed (which could happen with a pilot simply misreading the airspeed indication; if a gross weight calculation error is made; or an aircraft configuration error is made); or 2) rotation is initiated at a rate that is well in excess of the desired rate – which, in most cases, should be between 1.5 and 3.0 degrees per second.

It may be parochial, but I’ve always heard, and used, the term “flair” in connection with landing – i.e., the adjustment of the attitude of the airplane to decrease the rate of descent in preparation for landing. A tail strike may well be a result of a non-stabilized approach, but it is by no means the only reason for getting the tail on the concrete. More often than not, a tail strike on landing is due to a continuation of the rotation, beyond – and some cases well beyond – the level flight attitude. This normally comes from the fact that in order to achieve a level flight attitude (the attitude in which touchdown should occur – and please note … a level flight attitude for the aircraft gross weight and configuration is not necessarily a longitudinally level fuselage) there must be a control column movement aft to raise the nose. However, once the level flight attitude is achieved, any further aft column movement should be ONLY to maintain THAT established level flight attitude as the airspeed decreases (which will occur more rapidly with power reduction). Often the pilot will have more airspeed than necessary or decide to delay power reduction – and is of the belief that a continued aft movement of the controls is necessary … when it is not. In such cases, the airplane will continue to rotate nose-up until either the tail strikes the runway surface while still airborne, or the attitude achieved is so great that when the main gear tires contact the runway, the attitude is above that which will allow tail contact either with the main gear struts fully extended or fully compressed. If the airplane is landed in the attitude that would provide level flight (if sufficient power was used to maintain the airspeed achieved at the end of the flair) additional back pressure on the control column will be required (without raising the nose) to keep the attitude achieved at that point (i.e., level flight attitude) and the power reduction to idle will allow the airplane to land, somewhat firmly, but certainly not unsatisfactorily so, and with ample clearance to avoid a tail strike. Such an attitude also requires less time to fly the nose onto the runway, getting the airplane into a 3-point ground contact attitude sooner to better ensure directional control if/when required.

And for those who have discussed landing on an up-slope or down-slope runway – the “level” flight attitude should be the attitude that would allow constant airspeed flight parallel to the runway surface (very slightly climbing with up-slopes and very slightly descending with down-slopes).

If the flair is begun – taking less than 3 seconds to achieve the desired flight attitude – at an altitude that will put the main gear between 3 and 5 feet above the runway surface when reaching the landing attitude (level flight attitude) – if the power reduction to idle is begun on the initiation of the flare or, at the latest, upon achieving the landing attitude, the airspeed will decay rather rapidly – and will require additional backpressure on the control column – again, NOT to raise the nose, but to achieve and MAINTAIN level flight attitude. Touchdown will occur no later than 3 seconds after achieving this attitude. If the airplane is still in the air after 3 seconds in the flaired attitude, serious consideration should be given to executing a go-around.

oldrnU-2
1st Feb 2011, 17:17
Most management pilots get a promotion after a tail strike-DOH!!:{

SKS777FLYER
2nd Feb 2011, 01:14
OldrnU2 : Most management pilots get a promotion after a tail strike-DOH!!

The pilot in the discussion here happens to be a "Director of Flight". At AMR, managers of grades Managing Directors and beyond each April get a ca$h $tock payout (depending on AMR stock "performance") of some really HEFTY payments. They can (and most of them have) cash out immediately. A buddy of mine, a managing director got $900,000 CASH the first year of the payouts several years ago.!!!!

5 APUs captain
2nd Feb 2011, 15:26
757-300 tail clearance on take off is just 26 in (66 cm).......
Thanks God, I am just -200 driver!

stilton
3rd Feb 2011, 05:54
Tail clearance is really not an issue on the 753 however as the take off and landing speeds are much higher to compensate.


I have never seen it remotely close as it seems to lift off and land in a significantly lower attitude.


Incidentally, the 753 is a much nicer flying Aircraft than the -200. No dead spot in pitch on rotation or landing and more responsive in roll.


It may not be a rocket ship but it is a delight to handle :ok:

BOAC
3rd Feb 2011, 06:29
just 26 in:eek: Methinks you have been spoilt. That is a barn door!

sevenstrokeroll
3rd Feb 2011, 18:54
does anyone remember an AA B727 that hit the approach lights in brownsville on approach, diverted and the next crew missed the hole in the fuselage until they noticed pressurization was compromised?