Most people don't like to admit that they have dug themselves into a hole and need help to extricate themselves from their predicament. This is evident in the common tendency people have to minimize their problems when communicating with others, and has led to many adverse outcomes because people who could have helped did not fully understand the extent of the difficulty that pilot or crew were in.
This is especially true when pilots get into a low fuel situation. It doesn’t help that the regulations are not particularly clear on the meaning of minimum fuel vs. a fuel emergency. Neither the Airman’s Information Manual nor the FARs actually define what it means when a pilot declares a fuel emergency, but most pilots and controllers understand it to mean that the aircraft requires priority handling by ATC to proceed directly to the airport of intended landing due to low fuel. A declaration of “minimum fuel” is defined in the AIM and the AIM Pilot/Controller Glossary as an indication that “an aircraft’s fuel supply has reached a state where, upon reaching the destination, it can accept little or no delay. This is not an emergency situation but merely indicates an emergency situation is possible should any undue delay occur.”
There is more information available to controllers in the Air Traffic Control Handbook, which states that “a minimum fuel advisory does not imply a need for traffic priority. Common sense and good judgment will determine the extent of assistance to be given in minimum fuel situations. If at any time the remaining usable fuel supply suggests the need for traffic priority to ensure a safe landing, the pilot should declare an emergency and report fuel remaining in minutes.”
I would be willing to bet that a lot of pilots would be very surprised to learn that declaring “minimum fuel” to ATC does not imply a need for traffic priority. The controller could try to expedite the approach within the normal traffic flow, but the only way to indicate a need for priority handling is to declare an emergency. Even then, the controller would have to work within the restrictions of maintaining safe clearance from other aircraft and any limitations imposed by severe weather in the vicinity.
This misunderstanding is true even for Part 121 airline pilots and is becoming even more of an issue as airlines work to save fuel by minimizing reserves to reduce the weight of the airplane. Even with advanced navigation systems and sophisticated weather forecasting and reporting capabilities, it is still all too easy to get backed into a corner by a combination of weather and traffic when your reserves have been cut to the minimum amount possible.
Confusion Across Board
Reports to the Aviation Safety Reporting System bear witness to this confusion even on the part of airline pilots. One pilot reported that, due to a forecast for a chance of thunderstorms, the captain and crew decided to increase the fuel on board. However, this extra fuel was not enough, and after dealing with severe thunderstorms, wind shear and “holding and vectors all over the place,” the airplane had less than the fuel they would need to accept any further delays, and they communicated this to the controller. The reporting pilot’s lack of understanding of responsibility in that situation is evident in his shocked comment that “they had no plan!” It seemed that this pilot assumed that the controller would be aware of their fuel state and, while dealing with all the other aircraft under his control, would have a plan in his back pocket to deal with their situation.
The captain declared that they were “minimum fuel,” but because they were so hesitant to declare an emergency, they ended up going back and forth with the controller. First the controller cleared them direct to a VOR. They informed the controller that they could not go to that VOR and make it back to the airport. The controller tried to help them out by asking if they were declaring an emergency. They still did not declare an emergency but informed the controller that, if he insisted that they go to that VOR, they would declare an emergency. After the controller vectored them in a different direction, they broke out in the clear and were able to land with minimum fuel on board. The reporting pilot seems to have learned something from this since he stated that “next time we will declare an emergency.”