lunes, 30 de mayo de 2016

Approach and landing

Adapting Airline Procedures to General Aviation

The past thirty years has seen an extraordinary improvement in airline safety. This did not happen by accident and it did not happen because airline pilots suddenly got smarter. It happened because of culture change in the industry.

Prior to this culture change, every captain had his (and not many her at this time) own opinions on how to fly the airplane and how to handle problems that might arise. The first officer was there because the FAA said he had to be. Most captains were not open to suggestions and even less open to criticism. If a problem arose, the captain took over complete control of the airplane and improvised. There was virtually no standardization.
Airline management and the pilot unions realized over time that each pilot had some procedure or technique that worked well in a given situation. The huge task of collecting and evaluating the various procedures and techniques was begun. Each airline began to decide what worked best under which conditions for its particular kind of operations. The product of this effort was the constantly evolving standard procedures that are in use today.

The concept of standard procedures and checklists was so successful in improving the safety of airline operations that it is presently being integrated into other complex industries such as medicine, mining, and nuclear power production.

This "Airline to General Aviation" series is intended to expose pilots of light airplanes to some of the procedures used by the airlines. While not all airline procedures are applicable, many can be easily adapted for use in general aviation. The approach and landing phase of the flight is one of those areas.

Safer and Better Approaches and Landings

Passengers typically judge the quality of their pilot by the quality of the landing. A well executed flight through difficult conditions is not viewed favorably if the landing is not smooth. Conversely, a poorly planned flight that avoids disaster only through luck is considered to be a good flight if it ends with a smooth landing.
All good pilots know that a spectacular landing actually begins long before tires touch the runway, floats touch the water, or skis touch the snow. The first element in a spectacular landing is good preflight planning to ensure that the runway length and condition are adequate for the airplane upon its arrival. It is also necessary to keep up with any changes in the runway status or destination weather as the flight progresses. Once in the terminal area it is crucial to maintain situational awareness of the airplane's position relative to the landing runway as well as to any traffic that might be a factor. The final step in making a spectacular landing is to fly a stabilized approach.

To help in the goal of making spectacular landings we will examine three specific areas from the world of airline operations. These are preflight planning, the approach briefing checklist and the stabilized approach. After we explore these areas, we will examine three general aviation accidents that might have been avoided by utilizing these concepts.

Preflight Planning

Landing distance Table
The landing distance chart for the airplane type must always be consulted.
All pilots do preflight planning, right? There is the preflight planning that consists of measuring the distance, applying a rule-of-thumb for fuel consumption and then making sure that the airport has a runway that appears to be long enough.
Then there is airline preflight planning performed by a certificated dispatcher with access to sophisticated computer programs. This level of planning is probably not necessary for the general aviation airplane that normally uses less than half of the runway length and can land at a multitude of airport along the way if the weather turns unexpectedly sour. But a significant increase in safety can be gained by just a moderate amount of additional preflight planning effort. Our discussion here will relate only to making sure that there will be a suitable runway at the destination.
Gear Up Landing
Have an alternative plan in case the intended landing runway is suddenly unavailable.
The most basic requirement is to have a runway that is long enough for the airplane under the given arrival conditions. This seems too simple to overlook but the NTSB data base has numerous accidents that indicate otherwise. It is prudent and required by regulations to became familiar with all available information pertaining to the flight. This would include a check of NOTAMs.
Even though preflight planning might indicate a suitable runway is waiting at the destination, it is prudent to have an alternative plan in case there is a dramatic change in the wind or the pilot ahead of you closes the runway by forgetting to extend the landing gear.

Approaching the Destination

As the destination airport is approached, some information must be gathered from ATIS, AWOS, or whatever means is available.
This information must include:
•Actual landing runway and traffic pattern in use
•Runway length
•Runway condition (dry, wet, snow covered, etc.)
•Wind direction and velocity (including gusts)
•Surface temperature
•Any new anomalies
•Approach in use (if IFR)
Runway Orientation
A mental picture of the orientation should be developed.
Once the actual landing runway, traffic pattern, and instrument approach procedure (if any) has been determined, a mental picture of the orientation of the airplane to the traffic pattern, runway or approach can be developed. This is part of maintaining good situational awareness and can help to avoid confusion if things get busy. Once the mental picture is developed, it is easier to visualize where other traffic is located as it is reported by ATC or by position reports at non-towered airports.

The Approach Briefing

Approach Briefing Checklist
General aviation pilots must create their own approach briefing checklists. This is a sample for training purposes only. Click the image to download the sample in .pdf format.
An approach briefing is conducted by all airline crews to make sure that critical elements have been addressed. General aviation pilots will need to create their own approach briefing checklists appropriate to their airplane and type of operations. The example on the right might be used in a typical general aviation airplane for a VFR arrival. Another checklist for IFR operations should also need to be created. Airline crews have only one approach briefing checklist since all airline operations are conducted under Instrument Flight Rules. The approach briefing checklist should be conducted while nearing the destination airport but before entering the busier terminal airport. The checklist should be conducted whether the destination is in a busy Class B Airspace or in a rural, non-towered environment.

The aircraft status is simply stated as “normal” if there are no anomalies with the airplane or any of its systems. Any inoperative items and their impact on the approach and landing are reviewed at this time.

The fuel status calls for a review of the amount of flying time remaining as the approach is begun. This is really a way for the pilot to examine the options available in case the approach cannot be safely completed as planned.

ATIS instructs the pilot to review the ATIS information already received. This reminds the pilot of the landing runway, any special conditions.

Airport elevation, along with the surface temperature and altimeter setting will enable the pilot to calculate the landing distance and, in the case of some airplanes, the recommended approach speed.

The Traffic Pattern Altitude, along with the present altitude of the airplane and distance from the airport, lets the pilot determine how far the airplane must descend.

A review of any obstacles in the vicinity of the airport or along the path between the present position of the airplane and the airport is essential.

This is the time to review the minimum safe altitude that should have already been determined for the airport of intended landing.

The pilot must make sure that a strategy for a safe pattern entry has been developed.

The landing distance must be reviewed while considering of current runway and wind conditions.

The runway length for the actual available length of the landing runway should be reviewed at this time. It must be compared to the required landing distance which was previously determined.

The headwind/crosswind item calls for the pilot to review the surface wind speed and direction and to compare the direction to that of the landing runway.

The approach speeds item requires a review of the airspeeds to be flown on each leg of the traffic pattern and on short final.

The flap settings item requires a review of appropriate flap settings for the given conditions.

The stabilization altitude is perhaps a new term for general aviation pilots. Airline and corporate flight departments determine a stabilization altitude for each approach. Simply put, if the airplane is not stabilized on the approach by the time it descends to the stabilization altitude, a go-around or missed approach is initiated.

The go-around procedure is reviewed here. Barring any unusual circumstances, it will simply be a brief review of the standard procedure for the airplane.

The expected turn-off is reviewed here. It is helpful to review the airport diagram to know where the destination on the airport is located relative to the landing runway. This will let the pilot keep eyes on the runway during the landing roll rather than scanning the surrounding area looking for the desired FBO.

The Stabilized Approach

Pilots have been hearing about a "stabilized approach" since an instructor provided admonishment during the first few landing attempts. The chiding probably took the form of, "Don't chase the airspeed!" The airlines have taken the stabilized approach from the subjective to the objective by identifying key elements and quantifying them to the extent possible.

Click the image to download this sheet in .pdf format.
A general aviation adaptation of the stabilized approach might consist of seven elements. An eighth element simply states that is any one of the first seven is not being met, the approach is not stabilized and must be abandoned.
Though pilots might argue some of the items, wishing to delete or modify some and add others, the following is a good starting point for the general aviation pilot:
  1. The aircraft is on the correct flight path.
  2. Only small changes in heading or pitch are required to maintain the correct flight path.
  3. The aircraft speed is not more than the desired approach speed (VREF) +10 knots indicated airspeed and not less than VREF.
  4. The aircraft is in the correct landing configuration.
  5. Rate of descent is no greater than 500 feet per minute; if a descent rate greater than 500 feet per minute is required due to approach considerations, special attention must be paid.
  6. Power setting is appropriate for the aircraft configuration.
  7. All briefings and checklists have been accomplished.
  8. If the approach becomes unstabilized below the stabilization altitude, an immediate go-around or missed approach must be initiated.

The pilot needs to become familiar with the elements of the stabilized approach. This list is not intended to be used as a checklist during the busy approach phase. The first seven elements should be committed to memory so that a mental bell will sound when one or more of the items is amiss.
The concept of the stabilized approach applies to both VFR and IFR operations.


Short final
Completion of the approach briefing checklist will alleviate some of this demand by performing some of the necessary tasks before reaching the more critical points during the approach. 
The approach and landing phase is the busiest and most demanding phase of flight. Attention must be divided among flying the airplane, navigating to the proper position for pattern entry or initiation of the instrument approach, and communicating with ATC.
Once the approach briefing has been completed, it is time for the pilot to focus attention to the proper execution of the approach and landing. However, even a thoroughly planned approach demands a high level of concentration. The stall/spin accident continues to be one of the most common and most deadly accidents to occur during the approach phase of flight. The pilot’s primary responsibility is to operate the airplane safely within its performance envelope. The airplane is typically being flown at a reduced airspeed while in the airport vicinity. All pilots know that the stall speed increases during turns. Turns are necessary when the airplane is being maneuvered for landing so extra care must be taken to avoid an unintentional stall. Turns must be gentle and coordinated.

The airlines recognize the critical nature of this phase and dictate a "sterile cockpit" below 10,000 feet. This means that any conversation that is not directly related to the flight operation at hand is prohibited. General aviation passengers should be reminded that the pilot needs to concentrate during the approach phase and that they should refrain from making conversation. They may be asked to speak only if they see traffic or some other hazard that might be a factor.

Accident Analysis 

Better Preflight Planning Might Have Helped Prevent This Accident
Cessna 150 crash
The pilot of the Cessna 150 elected to land on a 1700 foot long grass runway with rising terrain and trees at both ends. The airport was equipped with a windsock. The winds reported from an airport about 33 miles southeast of the accident site, about the time of the accident, were from 210 degrees at 18 knots, gusting to 26 knots. The pilot reported that the winds were from the south at 20 knots, gusting to 30 knots. The landing was attempted on Runway 30. Preflight planning would have determined that a 90 degree crosswind of 18 to 26 knots would most likely be encountered on landing. This is well above the demonstrated crosswind component for the airplane. To make matters worse, the wind at the time of the accident had become a strong tailwind.
Cessna 150 crash
A witness, who was a pilot, stated that he observed the accident airplane as it was making its final approach to the airstrip. At the time, there was a "very strong, gusting tailwind, at 25-30 miles an hour." The landing approach seemed a little high, and the airplane disappeared from view as it neared the airstrip. The witness then heard the engine "go full throttle," and the airplane reappeared over the top of a knoll located 20 feet beyond the end of the airstrip. Just barely clearing treetops, the airplane flew in a northwest direction for approximately ¼ mile. It then turned to the left, and flew an additional 200 yards, where the right wing rose upward. The airplane then descended to the ground, coming to rest inverted.
Cessna 150 crash
The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

The pilot's improper decision to attempt a landing with an excessive tailwind, which resulted in an inadvertent stall while attempting to climb during a go-around. A factor related to the accident was the tailwind conditions and the rising terrain beyond the runway.
What can be learned from this accident? First, thorough preflight planning is essential. A weather briefing surely would have indicated the probability of high winds at the estimated arrival time. Second, a go-around decision must be timely. This accident could have been avoided if the pilot had executed a go-around earlier. An approach into rising terrain requires and extra measure of caution. Third, a pilot must always have and be prepared to execute an alternate plan. In this case, one alternate plan should have been a diversion to an alternate airport. Upon reaching the airport and seeing the windsock, it should have been obvious that a landing, at least in the northwest direction was not prudent on a relatively short, grass runway.

Accident Analysis 

An Approach Briefing Might Have Helped Prevent This Accident

runway orientation
The pilot of the Mooney M20E approached the North Las Vegas Airport after a flight from Reno.
The pilot of the Mooney M20E approached the North Las Vegas Airport after a flight from Reno. The weather was nearly perfect with scattered clouds at 12,000 ft. and a broken layer at 18,000 ft. Visibility was reported to be 25 miles. The wind was from 150 degrees at 5 knots. The pilot had reported his position as 2 miles southwest of the airport and had been issued a traffic advisory and had reported the airplane in sight. He was then instructed to follow that traffic landing on Runway 12. Shortly, the controller advised the pilot that it appeared he was adjusting to land on Runway 7 and that he had been assigned Runway 12. A heading of 300 degrees was suggested by the controller. The pilot acknowledged the instructions.
Mooney crash
The controller looked away and when he looked back, he saw exaggerated wing rocking as the airplane descended. Witnesses on the ground noted that the airplane rolled.
The controller looked away and when he looked back, he saw exaggerated wing rocking as the airplane descended. Witnesses on the ground noted that the airplane rolled.
The airplane crashed into a residence and exploded into a fireball. A passenger who survived stated that everything was fine until the pilot executed a steep left bank. He heard the pilot express concern vocally and noticed he was having difficulty controlling the airplane.
The NTSB lists the probable cause of this accident is as follows:
Mooney crash
The airplane crashed into a residence and exploded into a fireball.
The pilot's steep turn at low altitude that resulted in an accelerated stall while in the landing configuration, leading to a loss of control and subsequent ground impact.
What can be learned from this accident? First, pilots must be familiar with the airport layout and environment prior to arriving in the vicinity. Such awareness might have prevented momentary confusion over which was the assigned landing runway. An approach briefing might have prevented the pilot's confusion and his subsequent abrupt turn which apparently resulted in a stall/spin situation.

Second, the approach must be executed in such a way that the touchdown point will allow, considering runway and wind conditions, the airplane to be brought to a stop on the remaining runway. A long-standing rule-of-thumb says that the touchdown point must be within the first third of the runway. This is a reasonable practice for most general aviation operations but is not universally acceptable. A short runway, high density altitude, wet grass surface, snowy surface, higher performance airplane, or any number of other factors might dictate the need to touchdown closer to the runway threshold. Third, whenever an approach to a landing or the landing itself is not progressing as planned, the execution of a go-around is almost always the most prudent course of action.

Accident Analysis 

A Stabilized Approach Might Have Helped Prevent This Accident
TBM crash
The airplane collided with terrain and came to rest on residential property. (Official NTSB photo)
This accident involved a SOCATA TBM 700 executing a Runway 17 Localizer Approach to Leesburg, Virginia. The pilot was operating in actual instrument meteorological conditions, when the airplane decelerated, lost altitude, and began a left turn about 2 miles from the airport. Subsequently, the airplane collided with terrain and came to rest on residential property. The radar data also indicated that the airplane was never stabilized on the approach. A witness, a private pilot, said the airplane "appeared" out of the fog about 300-400 feet above the ground. It was in a left bank, with the nose pointed down, and was traveling fast. The airplane then "simultaneously and suddenly level[ed] out," pitched up, and the engine power increased. The witness thought that the pilot realized he was low and was trying to "get out of there." The airplane descended in a nose-high attitude, about 65 degrees, toward the trees. A review of radar data revealed an instrument flight rules (IFR) target approaching the Leesburg Airport from the north west. Examination of the last 4 minutes of radar data revealed the target turned toward the south about 9 miles from the end of runway 17. At that time the target was at an altitude of 3,100 feet msl and at a ground speed of 180 knots.
As the target continued to maneuver toward the south, it made a series of left and right hand turns along the localizer course. When the target was about 5 miles north of the runway, it was at an altitude of 1,700 feet msl and at an airspeed of 130 knots.
As the airplane continued to proceed toward the airport, it continued to make left and right hand turns along the course.
TBM crash
The approach was never stabilized. (Official NTSB photo)

As the airplane crossed over the final approach fix, about 4 miles north of the airport, it was at an altitude of 1,700 feet msl, at a ground speed of 91 knots.
When the target was approximately 3 miles north of the airport, it was at an altitude of 800 feet msl, at a ground speed of 80 knots.
Eighteen seconds later, the target began a left turn to the east before the data ended at 1445:29. The last radar target was located at 38 degrees, 57 minutes north latitude, and 77 degrees, 27 minutes west longitude, at an altitude of 700 feet msl, and at a ground speed of 68 knots.
The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

The pilot's failure to fly a stabilized, published instrument approach procedure, and his failure to maintain adequate airspeed which led to an aerodynamic stall.
What lessons can be learned here? This is an easy one. First, know what is meant by the term stabilized approach. Second, abort any approach that is not stabilized. Third, well, this one seems obvious, but is a mystery in this case. All instrument pilots should maintain proficiency such that flying a non-precision approach in actual instrument meteorological conditions is relatively easy. The pilot in the left seat was an instrument rated private pilot and the right seat was occupied by an airline transport pilot who also was an instrument flight instructor. Both pilots had completed the factory approved training for the airplane within the year preceding the accident. Proficiency should not have been an issue, particularly since this airplane is certified for single-pilot operation and two pilots were up front.
Editorial comment: It would seem that either the factory approved training was sub-standard or that a dangerous attitude was present in the cockpit. I have witnessed factory approved training that seemed rigorous on the surface, but provided a certificate to anyone who paid for the course. I have also seen dangerous attitudes in pilots who were otherwise very competent. Please see an article titled "It's All About Attitude." 


The general aviation accident rate is much higher than it needs to be and most accidents are preventable. Some procedures used by the airlines can be adapted for use in general aviation. The procedures dictated here are useable for either VFR or IFR operations. More thorough preflight planning, use of an approach briefing checklist, and making sure that each approach is stabilized will increase the chance of making those spectacular landings.

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