First of all, the planned fuel capacity of the aircraft is determined with reference to its average taxiing time and flight time. If it takes a long time waiting on the ground, which leads to insufficient fuel to arrive at the destination, the aircraft has to return to the landing field for refuelling. Secondly, in case of failure to receive am accurate take-off command from the air traffic control or any other accident, in order to keep passengers safe and avoid bad mental state of pilot, the aircraft will keep taxiing.  

First of all, regardless of the weather forecasts released by CAAC, the weather condition changes at any time. If the weather condition is not suitable for landing, the aircraft will not land. Meanwhile, for safety concerns or if the fuel is not sufficient for circling to wait for weather improves, the aircraft has to land on the alternate airport. In addition, when the weather condition is at the edge of standard, the capital will decide whether to land the aircraft, but captains hold different judgement on weather conditions. 

Possible reasons:

1. The standard of takeoff and landing is related to the aircraft, and different airlines may have different safety standards for the same aircraft;

2. According to CAAC, the captain is entitled to reject to fly when the civil aircraft, airport, and weather condition do not accord with the regulations, and flying safety cannot be guaranteed based on the civil aviation regulations. Meanwhile, captains may have different decisions. 

In any of the following circumstances, China Southern Airlines may change the type of plane or flight course, and will cancel, suspend, delay or postpone the flight in accordance with relevant regulations:

1. To comply with state laws, administrative regulations, rules, commands or requirements;

2. To ensure the flying safety;

3. Other uncontrolled or unforeseeable reasons.

If the carrier, due to any of the above reasons, cancels or delays a flight, and thereby fails to provide passengers with the booked seats (including cabin class), or stop at the stopover or destination, or help passengers take the proper connecting flight, China Southern Airlines would adopt any of the following measures considering the reasonable needs of affected passengers:

1. To provide available seats of the follow-up flight to the affected passengers on our priority list;

2. To complete flight transfer procedures for relevant passengers with the consent of such passengers and related carriers;

3. To change the segment listed on the original ticket, and arrange China Southern Airlines or other flights to send the passengers to destination or stopover;

4. To deal with it according to involuntary refund rules.

China Southern Airlines shall adopt all necessary measures to avoid the delay of passengers and their luggage of transportation. China Southern Airlines shall not assume any responsibility if it has adopted all necessary measures or can not adopt those measures. 

It refers to the fact that passengers require the refund for their tickets if the carrier cancels, delays, changes the flight, flies ahead of schedule or fails to provide the booked seats. 

1. When the flight is delayed or cancelled due to the reasons ascribable to China Southern Airlines, such as aircraft maintenance, flight allocation and aircrew condition, food and accommodation will be freely provided to passengers as appropriate.

2. If the delay or cancellation occurs at the departure due to reasons unrelated to China Southern Airlines, including but not limited to weather condition, unexpected event, air traffic control, airport fault, passenger’s problems, etc, food and accommodation shall be arranged by China Southern Airlines at the passengers' cost;

3. If the delay or cancellation occurs at the stopover, the carrier shall be responsible for offering food and accommodation for passengers for whatever reasons. 

If the cabin of the original class cannot be provided due to the change of flight or aircraft, China Southern Airlines will try to make proper arrangement as you wish. If you do not accept the arrangement, involuntary refund can be applied. 

Possible reasons:

1. The standard of takeoff and landing is related to the aircraft, and different airlines may have different safety standards for the same aircraft;

2. According to CAAC, the captain is entitled to reject to fly when the civil aircraft, airport, and weather condition do not accord with the regulations, and flying safety cannot be guaranteed based on the civil aviation regulations. Meanwhile, captains may have different decisions. 

Whether another flight can be arranged after the cancellation is determined by the following factors: the approval of the air traffic control, transfer of passengers to the next day, duty time restriction of aircrew and plane condition. In addition, flight safety and airworthiness is also taken into consideration. 

After cabin doors are closed, and everything is ready, the captain needs to make departure application to the air traffic control, which determines whether the aircraft can take off according to the traffic flow. Other aircrafts are not subject to the control of the traffic flow due to different destinations and directions. 

Given the massive aircrafts taking off and landing in airports, especially in busy ones, to ensure safe operations, air traffic control, in the light of flight flow in the air and on the ground, commands and controls the aircrafts in airports, requiring them to taxi and take off at the safe interval.  In some busy airports or at peak hours of general airport, air traffic is overloaded, so be ground traffic. In the case, it is normal that planes have to taxi on the runway and even wait for much longer time. 

Firstly, when a flight has been delayed for a long time, the carrier may shorten the delay time via the adjustment of flight operation plan, including the transfer of alternate aircrafts. But the alternate aircrafts are not available at every airport; secondly, temporary aircraft transfer plan is subject to the approval of air traffic control department. Therefore, even though there are alternate aircrafts, they may not be used for flight. 

At present, flight delay is the major reason for passengers' distrust upon the carriers, which is actually the shortcoming caused by the continuous provision of delay information. Each airline corporation has a dispatching center carefully arranging the flight of all the aircrafts. Once there is a problem at the operation, such as aircraft failure and airport closing, the whole flight will be affected. The dispatching center will make adjustment in time in the light of the actual situation so as to restore the normal flight operation as early as possible, notify the subsequent flights to make the corresponding preparations, and estimate a rough delay time. But the situation keeps on changing, and new problems may occur in the process of dispatching. A new delay can lead to the change of plans, thus making a flight put off again and again. 

There are many reasons for the carrier to cancel or merge flights due to the delays, such as air traffic control, airport and national important activities, etc. If the delay is for the reason of the carrier itself, on one hand, the carrier will compensate the passengers for their loss in rights and interests. On the other hand, the cancellation and merger of flights is to maintain the rights and interests of passengers, reducing the impact on subsequent flights and restoring flight operation as early as possible. 

Normally, the carrier will consider arranging another aircraft with sufficient resources and capacity so as to avoid long-time vicious delay. 

Delay for dispatching reason refers to the time delay caused by the adjustment to the flight of China Southern Airlines in the light of needs in the process of flight operation; delay for plan reason refers to the delay of subsequent flights due to deficient plan time of flights segments or deficient turnaround time of flight in plan formulation. 

As for the same flight, the carrier, airport, and air control department might obtain different information from different resources.  But as a carrier, China Southern Airlines will inform passengers of delay information as soon as possible. 

After a flight is cancelled, the carrier will provide passengers with the closest subsequent flight or the closest flight of the most suitable for the travel of passengers. Once the flight is changed, the contract of buying a new ticket shall be deemed to have been established. If passengers do not accept the arrangement, they can refund the tickets in full amount according to provisions of involuntary refund. If it is inconvenient for passengers to refund the tickets at the time, they can go to ticket offices directly affiliated to China Southern Airlines and show the corresponding certificates to refund their tickets within the valid period of the tickets. 

Unless the law provides otherwise, China Southern Airlines will offer the following services for your selection if the cancellation of a flight leads to the late takeoff of your flight, the failure of landing on the destination or stopover, or the missing of booked connecting flight:

1. To arrange the earliest flight of China Southern Airlines with available seats free of charge or prolong the valid period of tickets if necessary;

2. During the reasonable period of time, to arrange flights of China Southern Airlines or other carriers free of charge via the change of route, or send passengers to the destination stated on the thickets via other traffic ways acceptable to both parties, without additional charges;

3. To refund tickets according to provisions of involuntary refund.

Helps for abnormal flights:

1. When the flight is delayed or cancelled due to the faults of China Southern Airlines, such as aircraft maintenance, flight allocation, business, and aircrew, China Southern Airlines will provide dynamic information and food and accommodation to passengers without any charge as appropriate;

2. If the delay or cancellation occurs at departure due to the reasons unrelated to China Southern Airlines, such as bad weather, unexpected event, air traffic control, security inspection or passengers' fault etc., China Southern Airlines will offer the dynamic flight information and assist in the arrangement of food and hotel accommodation for passengers at their own cost;

3. If the delay or cancellation occurs at the stopover, China Southern Airlines will offer food and accommodation for passengers free of charge for whatever reasons.