How to Improve Air Safety?

How to Improve Air Safety?

The majority of accidents over the last years have occurred during the Approach, Landing and Go-Around flight phases. Accidents in Commercial Aviation and GA occurred during these phases of flight.

The lack of a Go-Around decision is the primary risk factor in approach and landing accidents and is the primary cause of runway excursions during landing. Even so, less than 5% of Unstabilized Approaches lead to a Go-Around.

The height at which a Go-Around is initiated during an approach presents different challenges and risks. Procedures and good training should clearly, and will make pilots to land safely all the time during any type of adverse weather conditions.

Major factors inducing crash involvement accidents during the approach and landing configuration.

All pilots need to focus on the last accidents to increase and studied accidents during approaches for improving the safety of all flights in Commercial and General Aviation to reduced flying out of see and avoid an accident or incident in conditions into that require them to fly using their all resources in your cockpit .

Learn and review accidents in the past it is very important how to improve Air Safety. So to make further improvement, Aviation Safety have focused on pilot skill, training and experience as a key questions.

One vast task is getting pilots to encounter complacency and better understand all the technology given to them so they can respond well to unusual events. Today the new generation of Pilots and also the technology in the cockpit works well 99% of the time. It's the 1% of the time when you look at the other colleague and say, 'Why this accident happened why the crew did that?

All Accident rates vary considerably by different type of situations, and also multiple causes are typically cited in investigation reports, so all pilots need to learn and study these accidents to acquire and improving safety all the time.

So far Safety is first all the time. The best Safety device in any Aircraft is a well-trained Safety Pilot.

Team Work is a priority all the time and a good CRM is the key to avoid accidents.

Factors Causing Visual Illusion

Eyeball Error LESSONS IN FLYING

If we were meant to fly we would have evolved a vision system more like birds.  Birds see more sharply than humans, with some birds of prey even sporting a second fovea - that part of the retina where light receptors needed for vision are concentrated.  Humans have one fovea. Birds are able to adjust focus more rapidly because they have extra muscles to change the eye's focal length. They have also developed enlarged optic lobes to process visual information faster. Their enhanced visual system is critical for flight. The human visual system provides 80 percent of total spatial orientation.  However, unlike birds, our vision is not adapted to the demanding nature of flight with the high speeds and three dimensions of movement requiring a lot of visual information to help judge distance, height and changes in these parameters.

It is the limitations of human vision that make it susceptible to illusions, particularly at night, in poor light or in conditions with few external visual cues. Powerful illusions can occur when the pilot, presented with limited visual cues, "fills in" the rest of the picture, or when what the pilot sees conflicts with a strong response from the sense of balance or orientation, which has its sensors in the inner ears. Approach and landing illusions can have serious consequences.

American Airlines Crash

One of the deadliest air crashes occurred 40 years ago in November 1965 when American Airlines flight 383 crashed 3 km short of the Cincinnati airport runway threshold. The aircraft was under full power during a visual approach in deteriorating weather conditions. Of the 62 on board, 58 died.

While the official listing of probable causes said the accident was due to the failure of the crew to properly monitor the altimeters during a visual approach into deteriorating visibility conditions, a common visual illusion was also implicated. Studies of illusory effects produced by lights on the Ohio River bank, viewed in conjunction with the more distant but 400ft higher runway lights, demonstrated that pilots approaching to land on this runway could receive visual cues that produced powerful sensations of being much higher than their aircraft's actual altitude.

Factors Causing Visual Illusion

A range of factors can induce illusions on approach and landing. In the airport environment, these include ground texture and features; off-airport light patterns, such as brightly lit parking lots or streets; the "black hole" effect along the final approach flight path; and uphill-sloping or downhill sloping terrain in the airport vicinity.

In the runway environment, the factors include the runway dimensions, runway slope (uphill gradient or downhill gradient), terrain drop off, approach and runway lighting and the condition of the runway. The cloud ceiling, visibility and obstructions to vision are key weather factors that contribute to illusions.

In the approach and landing phase of flight, visual illusions are most critical when you are transitioning from IMC and instrument references to VMC and visual references.  Any illusion can lead to crew corrections that cause the aircraft to deviate from the vertical or horizontal flight path.

Runway Appearance. The visual appearance of the runway, its dimensions, slope and lighting has a large role to play in creating illusions. Generally, pilots assume the runway is flat as they make their final approach to land. At a certain point from the runway, you expect to see a particular runway shape, which helps you judge whether you are too high, too low or correctly on the glide slope. If the runway shape is not as you expect, you will be tempted to make corrections to the flight to make the runway appear as it should.

Approach on Down Sloping Runway. If you are at a particular height and distance from the runway, a down-sloping runway will present a smaller image to the eyes. This will give you the same impression as if you were making a low approach to a level runway, as in both conditions you see less of the runway- So flying an approach to a down-sloping runway will seem like you are undershooting, even if you are on the correct glide-slope. If you are unaware of the sloping characteristics of the runway, you may fly higher to make the runway appear normal. This will look to you like you are on the correct approach path, but in reality you will be flying too high an approach. This could lead to an unstable approach and tricky landing, or a landing well down the runway, which may result in an overrun.

Approach on up Sloping Runway. The opposite will occur if you fly an approach to an up sloping runway. In this situation you will see too much of the runway, which will give you the impression that you are high and overshooting. If you attempt to correct this impression, you will fly a lower than normal approach, which could result in a hard landing, or possibly even a landing short of the runway.

Effect of the Width of Runway. The width of the runway is also an important consideration. It also depends on the width of the runway that you are used to operating on. At a certain distance and height from a runway, you expect to see the runway fill a certain amount of your peripheral vision, which helps you judge height from the runway and distance to touchdown.

Wider Runway. If you fly an approach to a runway that is wider than the one you are used to, at the same height and distance from the runway you will see more of the runway and this will give you the impression that you are much closer to the runway than you actually are. This may cause you to flare the aircraft at a much greater height from the runway than you would prefer. The result of this can be a high rate of descent and subsequent heavy landing, or at the very least an unstable approach and memorable arrival.

Narrower Runway. The opposite situation can arise when you fly into a narrower runway than the one you are used to. At the same height and distance from the runway, you will see less of the runway in your peripheral vision than normal. This may give you the impression that you have still some distance to travel before getting to that point where you begin the flare and reduce the throttle. You may well arrive on the runway before you are expecting to, with an unexpected hard landing.

Effect of the Length of Runway. The length of the runway is also a contributor to approach illusions. It also depends on the length of runway you are generally used to. At the same height and distance from the runway, a long runway will present a bigger Image to the eyes than a shorter one. The impression you will get is that you are too high on approach. This may lead you to make the same corrections as during the approach to an up-sloping runway, with the same potential outcomes of an unstable approach and possible undershoot. A shorter runway than you are used to will give you the opposite impression, that you are too low on approach. This may make you take corrective action similar to that with the down-sloping runway, and end up making an unstable, high approach.

Effect of Runway Lighting. The lighting on a runway can also cause illusions. Your depth perception is influenced by the lighting intensity and ambient conditions. Bright runway lights create the impression of being closer to the runway, and so the idea that you are on a stepper glidepath. On the other hand, low intensity lights create the impression of being further way, and so on a shallower glidepath. Also non-standard spacing of runway lights can modify your perception of distance the runway. If the runway is only partially visible, say, while on base leg during a visual or circling approach, the runway may appear further away or at a different angle.

Effect of Weather. Weather conditions can affect depth and distance perception. Flying in light rain, fog, haze, mist, smoke dust, glare or darkness usually creates an illusion of being too high.

Flying through fog. If you are on top of shallow fog about 300 ft in thickness, the ground can be seen, but when you enter the fog layer you will lose forward and slant visibility. This can create the perception of a pitch up, which can cause you to respond with an inappropriate nose-down correction that steepens the approach path.

Flying through Haze/ Light Rain. Flying in haze creates the impression that the runway is further away, inducing a tendency to shallow the glide path. When you are in light or moderate rain the runway may appear indistinct because of the rain halo effect, increasing the risk of misperception of the vertical or horizontal deviation during the visual segment flown after transition from instrument to visual references.

Flying through Heavy Rain. Heavy rain can also affect depth and distance perception. Rain on the windshield creates refraction effects that can lead you to believe that the aircraft is too high, with the risk of an unwarranted nose-down correction and flight below the desired flight path.

Effect of Approach Lighting System (ALS). In daylight, rain diminishes the apparent intensity of the ALS, resulting in the runway appearing to be further away. As a result you might be tempted to shallow the flight path. Rain at night increases the apparent brilliance of the ALS making the runway appear to be closer than it really is. The risk is that you will land short of the runway threshold.

Runway surface conditions can also induce illusions. Because a wet runway reflects very little light you may think that the aircraft is further away from the runway, contributing to the risk of a late flare and hard landing.

Prevention

To reduce the dangers of visual illusions on approach and landing, accident prevention strategies and personal lines of defence should be developed. You should assess your exposure to visual illusions on your route, and understand what conditions might increase the possibility of visual illusions. During the approach briefing you should review the hazards, including

Ceiling and visibility conditions.

Weather, including wind, turbulence, rain, showers, fog or smoke.

You should know the surrounding terrain features and man-made obstacles. At night, an unlit hillside between a lit area and the runway may prevent you from correctly perceiving surrounding terrain.

Specific airport and runway hazards, such as obstructions, the black-hole effect and off-airport light patterns.

The type of approach including the approach lights.

VASI or PAPI Availability.

Multi crew operations on approach and landing should adhere to defined task sharing after the transition to visual flying. This should involve

Monitoring by the pilot flying of outside visual references while referring to instrument references to support and monitor the flight path during the visual portion of the approach.

Monitoring by the pilot not flying of head down references while the pilot flying flies and looks outside for effective cross-check and back-up.

If you are flying in to an unfamiliar airfield, consider the implications of the runway dimensions. If it is narrower than you are used to, think of the approach illusions that may affect you on final approach to land.

Conclusion

Approach illusions are relatively common in aviation. Landing an aircraft is an intensive visual task, requiring both focal vision and peripheral vision to help build an accurate model of the aircraft's flight path so that the flare and touchdown can be accurately judged.

Visual illusions are a fact of life. While there is no substitute for good airmanship, being aware of the possible illusions that may arise during a particular flight will help you increase the safety of the flight.

Source: MEATBALL Naval Aviation Journal

Understanding and Analyzing Unstabilized Approach

Understanding and Analyzing Unstabilized Approach   

  

If we want to understand Error-Related Accidents we must put ourselves in the real of the problem, when aircraft accidents happen. Through my safety blog I always want to share the best approach to all Pilots all around the world, no matter in what Country you as a Pilot working for, to understand a respectable clear concept why accidents happen and why we as Pilots we can avoided and stay away in the prevention of accidents and incidents and working together with your Airline Safety Department to review your SOPs regarding circumstances  suggests that an accident resulting from landing from an unstabilized approach may be continue if we don’t place attention the examples of the last accidents in Global Aviation .

When an Airplane Crash happens there are many hypotheses about what’s going until the final investigation will closed and distributed the best recommendations regarding about that accident, but the most important evidence is to understand why this accident happened and why this incident can be avoided to prevent future accidents similar in the same conditions.

While the Annex 13 has been adopted pursuant the provisions to the convention on International Civil Aviation Aircraft Accident and Incident investigation, the manual makes it very clear to circulated good safety recommendations the state of the accident investi­gation authority of the State conducting the investigation, based on information derived from the investigation, made with the intention of preventing accidents or incidents.

The only objective for the investigation, as stated in Annex 13, the sole objective of the investigation of an accident or incident shall be the prevention of accidents and incidents. It is not the purpose of this activity to apportion blame or liability.

As a Human Being as Pilots should never judge anyone in this profession, there is always a lot of speculation about when an accident occurs, the most important thing is to study and focus where was the error and trying to identify on time for the prevention of future accidents.

Also, pilots may be conservative; to understanding the problem of unstabilized approach what that mean and focus and work hard of the analysis of unstabilized approach events.

All pilots are trained to base cockpit decisions on strategic and analytic reasoning, while realistic decision-making theory recommends that experts in naturalistic settings, like pilots, make decisions based on experience.

My best recommendation to all pilots is to study all this accidents and examined the willingness and ability of general aviation pilots to execute immediately a go around if you think you are involved  during unstabilized approach take immediate action on time , it doesn't matter if you are in a good clear conditions or in low-visibility conditions .  

The purpose of analyzing and working during your simulator training with your flight instructor it is good to practice to understand the strategies that pilots need to recognize, when you are approaching during unstabalized approach, to land the plane safely during the approach.

Flight Instructors must assist flight crews in their performance of stabilized approaches and provide cases of accidents and established programs that help understanding between pilots and team building, resulted in a significant reduction in unstabilized approaches and follow up and review your company SOPs .

Controlled flight into terrain accidents (CFIT ) are seen as the result of system-induced errors. In some cases, programs have been adopted that helped improve mutual understanding and improving pilots awareness of the risks associated with their actions during approach and improving training on unstabilized approaches and also to understanding and have clear that the new modern technology and display systems , it is highly questionable whether total system safety is always enhanced by assigning functions to automatic devices rather than human operators, and there is some reason to believe that flight-deck automation may have already passed its optimum point. This is an age-old question in the human factors occupation, and there are few guidelines available to the system designer.

Some automation-related aircraft accidents and incidents are discussed as examples of human factors problems in automated flight during the last fatal crashes involved commercial airlines, also you as a pilot need to understand well the concept of the Aeronautical Lighting and other Airport Visual Aids for a Safe Landing , some pilots forget this important perceptions during landing.

Always remember that the term Pilot Error is an action or decision of the pilot that , if not fixed and corrected on time , could be contribute to the occurrence of an accident or incident .

I want to be emphasis that the term Pilot Error does not imply that all errors are the fault of the pilot.

For this same reason I always share this phrase again with all the aviation community to stay away from accidents and incidents and fly safely all the time.

The day you think you don't learn more in aviation, it is the time you need to stop working and retired in this profession, because maybe you are going to make the mistake of your life. In aviation every day you learn new things.

Safety Experts Find Pilots Reluctant To Abort Landings

Safety Experts Find Pilots Reluctant To Abort Landings 

Airline pilots occasionally must decide whether to abort a landing because the approach isn't quite right, as with Asiana Airlines Flight 214, and safety experts are studying the industry reluctance to circle an airport and try again.

In the Asiana crash, the pilot's decision seconds before impact to try a "go-around" came too late and the plane crashed Saturday at San Francisco International Airport, killing two passengers and injuring more than 160.

More often, a mistake in the landing means a "runway excursion" where the plane runs off the end or side of a runway with little or no injuries. But safety experts have found pilots reluctant to abandon landings, so they are studying whether there would be fewer accidents if they performed more go-arounds.

"It's not that they're making the wrong decision necessarily, it's how they get led down that path," said Rudy Quevedo, director of global programs at the Flight Safety Foundation, which studies aviation accidents. "One of the biggest things that we see is that the pilots don't feel a threat -- they feel they can recover."

The foundation reviewed 16 years of accidents worldwide and found that one-third involved runway excursions. In studying the biggest risks for excursions, the foundation surveyed 2,500 pilots worldwide and discovered that a plane approaching a landing in an "unstable" way occurs in 3.5% to 4% of all approaches, according to a report released in February.

With more than 20,000 flights each day in the USA, the problems quickly add up. A stable approach means the plane is on the right path at the right height and speed, with the flaps and landing gear in the right positions. Unstable means one or more of those elements may be off.

In the Asiana crash, investigators found the plane was going much slower than the 137 knots intended at landing; it was at 103 knots three seconds before impact. Crash investigators said the flight-data recorder found pilots began increasing the throttle eight seconds before impact and called for a go-around 1.5 seconds before impact.

Major airlines have rules calling for pilots to perform go-arounds if their descents are unstable when they reach 500 feet above the ground on a clear day or 1,000 feet off the ground when pilots are flying with instruments.

But the foundation discovered that pilots perform go-arounds in only about 3% of their unstable approaches. The studies are continuing, but the foundation found reasons for the reluctance include a pilot's pride in completing the job, reduced fuel at destinations and the lack of attention on unstable approaches when planes land safely.

"It's not a pilot problem and it's not a management problem -- it's really an industry problem," Quevedo said. "We need to understand why."

John Cox, a former commercial pilot and president of Safety Operating Systems consulting firm, said more study is needed.

"My speculation is that using experience, (pilots) recognize that they're not very far out and they'll be within the stable criteria within a few seconds," Cox said. "It is very much worth a deeper look."

One aspect of the studies is whether a dramatic increase in the number of go-arounds would improve safety.

"What could be the risk?" Quevedo asked. "Could we make something worse, in effect, or would it be better?"

Earlier this month, the National Transportation Safety Board urged the Federal Aviation Administration to change its rules so that planes aren't placed on collision courses when one plane is performing a go-around and another plane is either taking off or landing on another runway.

The NTSB noticed five incidents in recent years - including three in Las Vegas - where planes got too close together when one performed a go-around and another plane was either taking off or landing on another runway.

Nobody was injured in the incidents and in several cases the pilots didn't even see each other.

The FAA said in a statement that the agency "thoroughly investigated the incidents and took aggressive steps to address the causes," and that the agency would respond formally to the NTSB.

The Asiana crash is expected to focus more attention on go-arounds.

"I think this Asiana accident potentially has the possibility of being one of those catalysts for increased training on go-around and accepting a go-around at an even earlier time," Cox said.

Source  : http://www.usatoday.com/story/news/nation/2013/07/09/asiana-crash-safety-landings/2501415/

Why Accidents Happen??

Why Accidents Happen??

When a plane crash occurs always people questioned what was happened, is a modern aircraft with the greatest technologies in aviation, but unfortunately these events happen.

Understanding what causes an accident often is like looking at an Iceberg. We see the accident as the tip of the Iceberg, but all coincidences why accidents happen.

Anyone involved in flying needs to learn the lessons of the past accidents, identifying the underlying causes and lessons learned from accidents to prevent aviation accidents.

Each accident case also includes a surgically precise analysis of what happened that is intended to find the casual factors in this mishap.

Pilots flying an airplane as a B-777 are a well-trained crew prepared to overcome any emergency occurring during any phase of the flight with several flying hours and experience to flying this type of aircraft.

Everything is hypothesis regarding this serious accident. Investigators in charge are the only people who can determine and collect all the evidences to evaluate what’s going on in this tragic accident.

Of course now Human Factors going to be a very important piece and how it applies in the investigation,

Human factors is about people, it I about people in their working and living environments, and it is a about relationship with equipment procedures and the environment.

Accidents impact people and all the Aviation community. Now the Investigators in charge are the only people to collect all the evidence and established what’s going on to avoid future accidents and prevent and avoided.

This information is only and hypothesis and also a professional interpretation, the investigators are the only people who will evaluate the FDR, FDA, Voice Recorders etc. to contributed what’s going with the B- 777 at the final moments during landing before crashed.

There are so many ways and so many places that errors can occur that you as a Pilot may wonder how it is possible for anyone to Fly Safely.

Even though this observation is to help to understand when Pilots, in general, are more likely to have accidents, it does not mean that you are invulnerable if you don’t match the outline.

My best recommendation to all Crews and the best attitude to have is that you are vulnerable at all times and that you should exercise caution at all times and fly safely.

The process of learning Is a good example of where human factors can play a major role.

Continuously I like to share this expression with all the Aviation Community.  The day you think you don't learn more in aviation, it is the time you need to stop working and retired in this profession, because maybe you are going to make the mistake of your life. In aviation every day you learn new things, always remember fly safely all the time.

http://www.youtube.com/watch?v=SXVmsm_pmUo

http://flightsafety.org/fsd/fsd_aug04.pdf

Pilot Guide to Takeoff Safety

Pilot Guide to Takeoff Safety

The concept of Safety is very important in Pilot Decision Making.

Pilot decision making often is a fundamental element in accident causal chains, where a Pilot didn’t make the best Safety Decision about flying or non-flying situation.

It is estimated that about ¾ all fatal General Aviation accidents are attributed to Pilot performance.

Safety is an important part of all the work we are doing both in the air or on the ground, for Safety is the prevention of accidents or to reduce them.

Pilots must work all the time improve to achievement more information in an effort to avoid an accident during takeoff or any phase during flying.

I want to review and share this interesting issue regarding some basic definitions to develop and explore always new ways to avoid accidents and incidents in General Aviation.

Safety First, Zero Accident has been around for a long time. It sounds respectable, but unfortunately, it never has been. Recognized and corrected both if you think do not remember some of the concepts of the variation of some basic operational considerations are shown in this article.

Expected Conclusion: Provide new decision aids and educational training and develop the appropriate existing material.

The Rules:

Some basic FAA definitions may be useful talking specific performance, also more detailed descriptions of FAA, ICAO requirements can be found in the material attached to this article.

Takeoff must be based on a smooth, dry, hard surface runway.

Takeoff Speeds :

VMCG (Ground): The minimum calibrated airspeed at which the airplane is satisfactorily controllable with the use of primary aerodynamic controls alone following the failure of the critical engine. Maximum permitted lateral deviation from the runway centerline is 25 feet. Use of nose wheel steering including rudder pedal steering is not permitted in the determination of VMCG.

VMCA (AIR ) : The calibrated airspeed at which , with all engines developing maximum thrust and when the critical engine is suddenly made inoperative, it is possible to recover control of the airplane with that engine still inoperative and maintain straight flight either with zero yaw or , at the option of the applicant, with the angle of bank of not more than 5 degrees. During the recovery , using a maximum rudder pedal force 180 lbs., the airplane must not require any exceptional piloting skill, alertness or strength to prevent a heading change of more than 20 degrees.  

V1  Takeoff Decision Speed : As speed selected by the applicant which must be at least the minimum calibrated airspeed at which controllability is shown (during the takeoff run ) to be adequate to safely continue the takeoff using normal piloting skill when the critical engine is suddenly  made inoperative.

V1 may not be less than VMCG or greater then VR.

V2 Min Takeoff Safety Speed : May not be less than 1.2 Vs for turbojet powered airplanes without provisions for obtaining a significant reduction in the one engine inoperative power- on stalling speed.

May not be less than 1.10 VMC.

V2 Takeoff Safety Speed : Must be selected by the applicant to provide at least the required gradient of climb but may not be less than V2 MIN or VR plus the speed gained before reaching a height of 35 feet above the takeoff surface .

VMU Minimum Unstick Speed : The calibrated airspeed at and above which the airplane can safely lift off the ground and continue the take off .

VR Rotation Speed : May not be less than V1 or 1.05 VMCA or the speed that allows reaching V2 before the airplane reaches a height of 35 feet above the takeoff surface , or a speed that will result in a VLOF not less than 10 percent above VMU if the airplane is rotated at its maximum practicable rate with all engines operating (5 % with one engine inoperative).

VLOF Lift Off Speed : Is the calibrated airspeed at which the airplane first become airborne .

Speed Abuses :

It must be shown that the one engine inoperative takeoff distance using a rotation of 5 Knots less than VR does not exceed the corresponding one-engine –inoperative take off distance using the established.

Reasonable expected variations in service from the established takeoff procedures for the operation of the airplane (such as over rotation of the airplane or out of trim conditions) may not result in unsafe flight characteristics or marked increases in the scheduled takeoff distances.   

Distance :

Acellerated –Stop Distance : The sum of the distances necessary to Accelerate the airplane from a standing start to V1 and come to a full stop from the point at which V1 is reached assuming that the critical engine fails at V1 . The accelerate-stop –distance may include a Stopway.

Stopway: An area beyond the takeoff runway no less wide than the runway and centered or the extended centerline of the runway , able to support the airplane during an aborted takeoff  without causing structural damage to the airplane , and designated by the airport authorities for use in decelerating the airplane during an aborted takeoff .

Clearway: An area beyond the runway, not less than 500 feet wide,centrally located about the extended centerline of the runway, and under the control of the airport authorities. The clearway is not expressed in terms of a clearway plane, extending from the end of the runway with an upward slope not exceeding 1.25 percent, above which no object nor any terrain protrudes. However, threshold lights may above the plane if their height above the end of the runway is 26 inches or less and they are located to each side of the runway. The takeoff distance must not exceed the length of the runway plus the length of any clearway except that length of any clearway included must not be greater than one half the length of the runway. Also one half the distance from liftoff to the end of takeoff run must occur over the runway.

 

Takeoff Distance : The greater of the horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface considering an engine failure at V1 or 115 percent of the horizontal distance along the takeoff path, with all engines operating  from  the start of the takeoff  to the point at which the airplane is 35 feet above the takeoff surface.

Takeoff Run : If the takeoff distance includes a clearway, the takeoff run is the greater of the horizontal distance along the takeoff path from the start of the takeoff point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface considering an engine failure at V1 or 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start or the takeoff to a point equidistant between the point at VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface.

Takeoff Path : The takeoff path extends from a standing start point in the takeoff at which the airplane is 1500 feet above the takeoff surface, or to a point at which the transition from the takeoff to the enroute configuration is completed at an appropriate speed – whichever point is higher .

 

The airplane must be accelerated on the ground to V1 at which point the critical engine is made inoperative and remains inoperative for the rest of the takeoff. The airplane must then be accelerated to V2 during which time the nose gear may be raised off the ground at a speed no less than VR.

The landing gear retraction cannot be begun until airplane is airborne.

The slope of the airborne part of the takeoff path must be positive. The airplane must reach V2 before it is 35 feet above the takeoff surface and must continue at a speed as close as practical to, but not less than, V2 until it is 400 feet above the takeoff surface.

http://www.faa.gov/other_visit/aviation_industry/airline_operators/training/media/takeoff_safety.pdf

Always Fly Safely !!!!