Now that the HEF tower closes at 1600, we wish to share the following information to our local GA pilots, and remind them to be vigilant when flying in, and around, the Manassas Area.
When the tower closes, HEF airspace changes from Class D airspace to Class E airspace. Which means that the airport is uncontrolled, and pilots are free to give themselves permission to takeoff and to land. The AIM is clear that, under those conditions, pilots are expected to self-announce their intentions and locations around the airport in order to provide safe aircraft separation. In this case all aircraft using HEF are required to us the HEF Common Traffic Advisory Frequency (CTAF) which is the Tower Frequency (133.1) even when the tower is closed. All pilots are expected to adhere to the AIM guidance (which is not regulatory) no matter what they are flying. And the great majority of pilots do just that. They provide safe separation when the tower is closed.
Aircraft arriving at HEF any time, day or night, are monitored or control by POTOMAC TRACON (PCT) since they are within the Special Flight Rules Area (SFRA). Pilots are encouraged to review the current Notices to Airmen (NOTAMs), specifically HEF 01/046, prior to taxiing.
PCT provides Air Traffic Control (ATC) services Instrument Flight Rule (IFR) aircraft until their flight plan is terminated. This is not the case for GA aircraft on VFR flight plans, when the tower is closed and HEF airspace is Class E. They are on their own but they are still required to comply with the requirements of the SFRA. However, you it is expected that all aircraft now have traffic advisory avionics (ADS-B).
“Automatic dependent surveillance–broadcast (ADS–B) is a surveillance technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling it to be tracked. The information can be received by air traffic control ground stations as a replacement for secondary surveillance radar, as no interrogation signal is needed from the ground. It can also be received by other aircraft to provide situational awareness and allow self-separation. ADS–B is "automatic" in that it requires no pilot or external input. It is "dependent" in that it depends on data from the aircraft's navigation system.”
In the corporate flying world, they fly into towered and non-towered airports every day. The operations at towered and non-towered airports most often follow the desired operations from the AIM. As mentioned above, when the HEF Tower closes in the evenings, the operations should fall back to non-towered operations. Pilots should use extra caution arriving HEF, not to confuse airfields due to the proximity of Dulles Airport (IAD). Pilots flying for Part 91, 91(K), 121, and 135 companies are well versed in flying into non-towered airports as part of their daily operations. In addition to the guidance provided in the AIM, their operations are probably governed by company flight operations manuals as well, providing an additional layer of safety.
The primary rule for pilot safety is still SEE AND AVOID, and compliance with AIM guidelines regarding safe aircraft separation is paramount.
