[ professional classification ] flight [ Article ID ] 2-2009-0062
The aircraft release system is a more complex system. Modern aircraft is almost all modern high-tech achievements. Not only the system equipment is all-encompassing, but also the software and hardware technology has a wide range of extensions, and there are many kinds of ground communication navigation and facilities. When the plane is driving in the air, it is impossible to be unconstrained, unconstrained, and the appearance of wind and rain or special circumstances often bring disaster to the aircraft with limited performance. In order to make the aircraft safely rise and fall in a rapidly changing environment, it requires the close cooperation of many professionals such as flight, dispatch, ATC, aircraft, weather, business, and field work. Each department is like a chain of responsibility. If there is a lack of coordination, if any link is disconnected, security will be lost.
First, the current operation status of the flight dispatch (scheduling) work
For many years, the company's (provincial bureau) dispatching and releasing functions are all responsible for the station transfer. The working methods and working procedures are basically old routines. Therefore, our dispatching work is the same as other companies, and there are also many problems. Most of them are limited to collecting and transmitting flight telegraph services, mechanically releasing aircraft, answering other units' inquiries about flights, providing logistic support (such as arranging crew rest and pick-up, ordering meals, arrangements for irregular flight passengers) and other transactional work. The release function and management function of the dispatch were not really played. In fact, it should also include calculating aircraft performance, balancing aircraft loads, determining the optimal economic cruising altitude and optimal fuel consumption for the flight, and the flight route, weather conditions (takeoff airport, destination airport, alternate Airports, crew members, flight readiness, route communication and navigation conditions should be comprehensively understood, plan flight plans, supervise and inspect the quality of work of each support department, and collect all information on the currency (including planned, pre-flight, in-flight) After the flight, the release aircraft will be dispatched with modern and standardized technical management means.
Second, the current status and pressure of flight crew
In recent years, our company has developed rapidly and expanded rapidly. The fleet has grown from two original An-24, and now it has grown to 10 Boeing 737-300s and the fleet of three Boeing 767-300s that will be in place. When Yunan Airlines was established in July 1992, there were only 42 pilots. Now there are 152 pilots in the program. Therefore, there are many â€œnewbiesâ€, narrow knowledge, uneven quality, weak sense of scale, and a large knowledge gap. The phenomenon. The new pilot still needs a few spring, summer, autumn and winter exercises to mature, and the old pilots need to be retrained to update their knowledge.
The aircraft is directly in the hands of the crew. Although the dispatchers and maintenance personnel are also involved in the flight production activities, their orders must be executed by the crew. The crew is the last gateway to safe release. Here are a few typical examples that our crew has encountered:
Problem 1: Once the APU is faulty, the crew is ready to take off in the standard form of flap 5 and bleed air. According to the captain of the loading table, it was found that the overload was 500 kg, and it was required to reduce the load (7 passengers were pulled down). Fortunately, the other unit promptly reminded that the flaps 1 can be used to open the bleed air to increase the weight limit. The results did not result in flight delays and economic losses.
Question 2: On the flight of a flight, the defensive brake is faulty. According to MMEL, the locomotive is considered to be airworthy and can be released. The crew checks the third volume of the operation manual according to the requirements of MMEL and should reduce the load as required. The dispute between the two sides failed, and the crew had no choice but to continue flying.
Question 3: An aircraft performs the Kunming-Lijiang-Kunming flight mission. The crew found that the actual weight on the manifest was inconsistent with the actual take-off weight. The empty weight of the round-trip manifest differed by 250 kg, and the maximum allowable take-off weight was not filled.
Question 4: As for the flight to Beijing, the position of the center of gravity calculated by the loading department is extremely close to the envelope. The captain had no bottom in his heart and requested to adjust the loading position of the cargo. The flight was delayed for 25 minutes.
On the comprehensive issue, it is not difficult to find that dispatchers, dispatchers, maintenance personnel and various service support personnel have a negligible effect on flight safety. They help and remind the pilot to solve the problem in various ways. However, the problem encountered in the reality is that the dispatching department and the relevant support departments have not performed their functions properly, and many problems have been piled up in the cockpit to be decided by the pilot. It is bound to increase the difficulty and increase the pressure on the pilot's work. The occurrence of each accident is firstly the occurrence of individual errors. If it is not discovered and corrected in time, other errors occur one after another. Under the joint action of each error, it is a danger, such as when the pilot finds it late or not found. This danger can cause inevitable accidents. Under the current situation, the company must have safe and profitable aircraft release. While increasing training, strengthening functions, and improving the quality of personnel in each support department, it is necessary to improve the pilot's self-distribution ability.
Third, the pilot's self-distribution ability requirements
In any foreign pilot training, self-dispatch training is an indispensable course. It is also an important criterion for measuring whether pilots can conduct commercial and transport flights. The purpose of the training is to make the aircraft safe and economical to fly. The pilotâ€™s self-distribution ability should reach:
1. Know how to calculate the performance of aircraft takeoff, including calculating the takeoff weight and takeoff speed under different environmental conditions, using the thrust reduction takeoff and improving the climbing technology, etc., and know how to calculate the optimal cruising altitude and landing performance;
2, familiar with the company's fuel regulations, will calculate the optimal fuel consumption;
3. Familiar with company flight regulations and special airport regulations, including flight characteristics of high temperature altitude airports;
4. Will use MEL, CDL, etc. When an aircraft has instruments or equipment that are not working, it can carry out limited flights according to certain restrictions and working procedures;
5. Calculate the position of the center of gravity, understand various weather charts and weather telegrams, and formulate flight plans.
The core of the above requirements is familiar with aircraft performance. Our company is located in the Yunnan-Guizhou Plateau. The airports in the province are mostly high-altitude airports, such as Kunming, Lijiang, Dali, Simao, Diqing (10,761 feet above sea level) and Linyi Airport. The geographical environment and climate characteristics are complex and the aircraft performance is Affected to a large extent. The pilot's ability to self-sign is also particularly important.
Fourth, the flight of the high altitude airport
1. Climate characteristics and geographical environment of Yunnan Plateau Airport
The climate in Yunnan has a complex climate. During the rainy season (May-October), there is more precipitation, and thunderstorms appear more frequently. The weather is often just a few miles away, and the clouds are full of clouds and thunderstorms. During the dry season (November-April), low clouds and low visibility are common, with an average wind speed of 5-8 m/s in the afternoon and a gust of 12-21/sec. There are often low-altitude wind shears near the airport. During the approach, severe bumps often make the aircraft difficult to maneuver. The terrain around the airport is steep and there are many mountains.
Here, try Kunming Airport as an example. The average altitude of Kunming Airport is 6210 feet (1895 meters), the length of the runway is 11520 feet (3400 meters), and the north end of the runway has more obstacles and poor clearance conditions, which has a greater impact on flight and more load shedding. It is precisely because of the complicated situation of Kunming Airport that the General Administration of Aviation Safety has designated Kunming as one of the eight special airports in the country to remind companies to pay attention.
Chart 1 takes the temperature of Kunming Airport as an example. The highest monthly temperature appears in May, June and July, and the average monthly temperature in the five years from 1990 to 1994 is 30.9 Â°C.
2. The impact of high temperature and high altitude airports on aircraft performance
When the temperature rises: the air density becomes smaller, the air quality of the engine is reduced, and within the rated temperature range, the engine can compensate for the thrust loss, but the engine thrust is reduced when the rated temperature is exceeded.
As can be seen from Figure 2, the takeoff thrust of Kunming Airport is reduced by 1600 lbs compared to Guilin Airport. When the temperature of Kunming Airport rises to 25 Â°C, the takeoff thrust begins to decrease drastically.
When the altitude of the airport increases, the air density becomes smaller, and the air mass of the engine is reduced, so that the engine thrust is reduced.
When the altitude of the airport increases and the temperature rises again: the air density becomes smaller, the lift of the wing at the same angle of attack becomes smaller, and the higher vacuum speed, larger ground speed and longer runway are required for takeoff. The ground distance of 35 feet is longer, and the ability to exceed the height of the obstacle is reduced by the maximum allowable takeoff weight.
As shown in Figure 3, the higher the altitude of the airport, the longer the takeoff run distance to 35 feet. Lijiang Airport (7,334 feet above sea level and 8,200 feet long runway), compared with Kunming Airport, Lijiang needs about 500 feet of running distance, about 7,000 feet. In Guilin, it takes about 5,200 feet to run. It is conceivable that the difficulty of flying at a high altitude airport.
Figure 4 shows the effect of high temperature, high altitude airports on the single-lift performance of the aircraft.
Figure 5 shows the difference in weight when using an improved climb at different altitudes.
Here is a comparison example of takeoff analysis of three airports in Guilin, Kunming and Lhasa (see Appendix 1). As can be seen from the example, as the altitude increases, the difference in allowable take-off weight is quite significant.
In summary, both high altitude and high temperature factors can reduce aircraft performance. If the takeoff is interrupted, the ground distance of the brakes will also need to be longer. Improved climb performance can increase a little maximum takeoff weight, but not enough to offset the effects of high altitude/high temperatures. It should also be noted that elevated temperatures and altitudes tend to increase the engine EGT during takeoff and climb, and the life of the engine is therefore reduced. We have specially prepared a technical notice "Use of Reduced Thrust Takeoff", requiring pilots to use as much as possible to reduce the thrust when conditions permit, to improve the safety factor, and the impact of high altitude on flight when the pilot is self-signed. Should be given enough attention.
3. When a system or equipment malfunction (MEL) or external component incomplete (CDL), the impact on high-altitude, high-altitude airport flight is also extremely prominent.
The company's operating objectives are nothing more than: safe transportation of passengers and goods, creating economic benefits. The pilot's self-distribution is to use the most appropriate performance, safe flight and profit on the ground, in the air. The anti-lag brake does not work, one or two main fuel tank booster pumps fail, and the loss of the slat actuator sliding seal will reduce the take-off weight by a large margin, or increase the fuel demand and reduce the load. At high temperature and high Under the conditions of altitude, the economic benefits are greatly affected, and even unprofitable.
The flight at the high temperature altitude airport must have sufficient safety margin, that is, when one engine fails, the remaining engine can be used to continue to fly to the destination or return to Kunming, or the landing conditions are not available, single recovery Flying, must be able to climb over complex terrain and high mountains, safely to the alternate field with sufficient backup fuel, and the aircraft's payload is greatly limited. If the aircraft takes off at Lijiang Airport, the anti-lag brake failure can not be ruled out, resulting in a decline in aircraft performance. If the load is not reduced according to regulations, it will inevitably cause the aircraft to be unsafe, and the pilot must self-distribute. The runway length of Lijiang Airport is only 8,400 feet, and the takeoff weight is limited by the length of the runway. Through the comparison of the three flaps of the performance analysis chart (see Attachments 2, 3, and 4), Lijiang's use of improved climbing or reducing the position of the take-off flaps does not increase the take-off weight. This requires the crew to carefully check the performance analysis table when flying at high temperature altitudes. If OAT = 10 Â° C, breeze, take off using a non-standard aircraft form ( flap 5, bleed air) to obtain the maximum take-off weight allowed. According to the weight reduction calculation method that the anti-lag brake does not work (we summed up two simple calculation formulas):
Limit weight for anti-lag brakes not working = 54,600 (run length of runway) - 7,000 = 47,600 kg (see Appendix 5 for calculation formula).
This means that the maximum takeoff weight allowed for the anti-stagnation brake is 47,600 kg, which is not profitable for high-temperature and high-altitude airports.
V. Pilot self-signed training and regulations for high-temperature and high-altitude airport flights
Boeing aircraft can fly safely under many inferior conditions, but the pilot must calculate the performance data accurately and timely when self-signed, and determine the appropriate operating procedures to ensure flight safety.
Since July 1994, we have targeted the pilots to start uninterrupted, practical self-distribution training, familiar with aircraft performance. So far, four Boeing performance engineers have been invited to conduct training in the performance class. International performance engineers, flight performance instructors, and maintenance engineers have also been invited to hold various lectures in various forms. During the training period, the company also invited business staff, dispatch personnel and pilots to learn together, strengthen understanding and communication. In the case of weak technical strength, we overcome the difficulties, analyzed and edited the "B737-300 Airport Takeoff Performance Flight Manual" issued to all flight personnel, all relevant support departments and equipped machines, so that the flight can be relied upon, for the aircraft Release provides accurate performance data.
For the flight of high-temperature and high-altitude airports, we have formulated a series of strict regulations, such as the "Technical Regulations on the Implementation of Lijiang Airport Flight Tasks" and the "Technical Regulations on the Implementation of Dali Airport Flight Tasks". In addition to the four-stage preparation for normal flight, the pilot must also use the takeoff performance analysis chart or the operation manual or flight manual to calculate the normal takeoff performance. It will use a non-standard aircraft configuration to adjust the non-standard takeoff performance ( Wet, slippery, stagnant water, snowmelt runway), can implement the improved climbing technology and the correct use of the reduced thrust takeoff, will correctly use the reduced thrust takeoff, will correctly use MMEL, CDL and so on. When passing the weather standard theory test, it is necessary to pass the above assessment. When carrying out high-altitude airport missions, it must be equipped with two captains. Pilots must pass the route to check with the flight. Only after the approval is passed can the task be performed separately. For balanced stowage, the fuel plan, the captain must personally check and verify.
6. Strengthening the current dispatch and release system, my flight safety service
Although our pilots' self-distribution ability has been greatly improved, due to various factors and conditions, it is difficult for flight crews to obtain all the information for safe flight. Moreover, in the short time before take-off, it is very It is difficult to ensure that the data identified or checked by the self-delivery is correct, and it is also difficult to avoid delays. In order to truly ensure flight safety, the safety gate must be moved forward. In other words, it really forms a mechanism for dispatching as a release center, timely coordinates and directs transportation production, speeds up flight information transmission, and checks whether the release factors, balance loading, aircraft airworthiness, weather and other release factors are accurate and reliable. To strengthen the supervision and inspection of the quality of work and standard procedures of various support departments, reduce the burden on pilots, and reduce the workload in the cockpit. This requires us to increase investment in dispatching work, such as establishing a computer information network, and provide comprehensive training for dispatched personnel (even including cockpit observation and simulator), and train a group of well-trained as soon as possible. Qualified dispatched personnel, do a good job in all technical construction work, change the original backward, simple and simple working methods, and formulate applicable and operational procedures to form a consistent decision-making process.
Flight dispatch is a very important job, and safe flight requires a complete and accurate flight dispatch to provide effective flight planning and information support. "There is no rule, no way to become a garden." If the flight safety is guaranteed, it is because the safety regulations of various flights are strictly observed.
(This article was published in Civil Aviation Management 1996.10)