October 1, 2005
By John S. Yodice
John S. Yodice is general counsel for AOPA.
What is night flying under FAR Part 91 (general operating and flight rules) and Part 61 (certification of pilots and instructors) could be confusing because night is defined or described differently in different places in the regulations. What helps obviate the confusion is pointing out the not-so-obvious fact that it is only in two significant places where it is different from the technical regulatory definition of "night."
The technical regulatory definition of night, FAR 1.1, is "the time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the American Air Almanac, converted to local time." Civil twilight ends in the evening when the center of the sun's disk is 6 degrees below the horizon and begins in the morning when the center of the sun's disk is 6 degrees below the horizon. That's getting pretty dark, as pilots familiar with the horizon understand. The American Air Almanac contains tables that show evening civil twilight and morning civil twilight for different latitudes. According to the FAA, knowing the latitude in which we are located, and using these tables, we can determine when evening civil twilight ends and morning civil twilight begins. We can then convert these figures into local time, and calculate the time spent in night flying accordingly. Most of us rely on tables published in weather reports or local newspapers, or on television or the Internet. Most of us are satisfied that these approaches, applied conservatively, meet the intent of the regulations.
This technical regulatory definition (not the two exceptions), applies to such important regulations as VFR weather minimums, VFR fuel requirements, and pilot certification requirements for night flight training.
The basic VFR weather minimums of FAR 91.155, which are complicated, yet which every pilot is held to know, for the most part do not differentiate between night and day. It is only for operations in Class G (uncontrolled) airspace that the regulation specifies some higher minimums for night flight. The minimums in the other classes of airspace, all controlled (Classes A, B, C, D, and E), are the same, night and day.
The daytime minimums for Class G airspace (below 10,000 feet msl and above 1,200 feet above the surface) are visibility of 1 mile and clearance from clouds of 500 feet below, 1,000 feet above, and 2,000 feet horizontal. At 1,200 feet or less above the surface (regardless of msl altitude) the daytime cloud clearance minimum is "clear of clouds." That's pretty significant. At or below 1,200 feet agl in uncontrolled airspace, we can operate daytime VFR with as little as one-mile visibility and clear of clouds.
At night, the visibility minimum for uncontrolled airspace increases to three statute miles for both altitude spectrums, making it the same as in controlled airspace. The cloud clearance minimums at night, while the same as controlled airspace for operations above 1,200 feet above the surface, increase for lower altitude operations from "clear of clouds" to the same as controlled airspace, i.e., 500 feet below, 1,000 feet above, and 2,000 feet horizontal distance from clouds. So, at night, the VFR weather minimums in all uncontrolled airspace up to 10,000 feet msl are the same as controlled airspace. In other words, there are no relaxed VFR weather minimums at night in uncontrolled airspace.
Helicopters are a special case. Day or night in uncontrolled airspace, a helicopter may be operated clear of clouds if operated at a speed that allows the pilot adequate opportunity to see any traffic or obstruction in time to avoid a collision. Another special case is airplanes (or powered parachute or weight-shift-control aircraft) in an airport traffic pattern in uncontrolled airspace. If an airplane is operating at night in an airport traffic pattern within one-half mile of the runway, it may operate with as little as one-statute-mile visibility.
The fuel requirements for flight in VFR conditions, as specified in FAR 91.151 (see "Pilot Counsel: VFR Fuel Requirements," January 2000 Pilot), are increased for night operations. At night, a flight under VFR conditions must begin with enough fuel to fly to the first point of intended landing, and to fly after that for at least 45 minutes assuming normal cruising speed. The daytime minimum is 30 minutes. The fuel requirement for rotorcraft VFR flight is not different for night. Day or night, the flight must begin with 20 minutes fuel reserve. As a reminder, in computing these fuel requirements a pilot must consider wind and forecast weather conditions. The fuel requirements for flight in IFR conditions are not different for night or day.
A specified amount of night flying is required for certification as a private or commercial pilot. For example, under FAR 61.109, an applicant for a private pilot certificate must generally (there are restrictive exceptions) have at least 3 hours of night flight training that includes a long cross-country flight and 10 takeoffs and 10 landings in a single-engine or multiengine airplane, depending on the rating sought. Under FAR 61.129, an applicant for a commercial pilot certificate has comparable night flight-training requirements and exceptions. There are similar night flight-training requirements for helicopter and other ratings. All of this night time is required to be computed with reference to the technical regulatory definition of night in FAR 1.1.
On the other hand, here is one of the places that the definition of night is different from the FAR 1.1 definition. FAR 61.57(b) contains the recent night-flying experience requirements to carry passengers at night. The title of the regulation uses the term "night" but only implicitly defines that term as the "period beginning one hour after sunset and ending one hour before sunrise." This definition is narrower. It makes shorter the period of darkness when this night flying experience may be gained.
To refresh, the rule requires that a pilot must have made at least three takeoffs and three landings to a full stop during nighttime, as it is here narrowly defined, in order to be current to carry passengers during a nighttime period defined in the same way. The required takeoffs and landings must have been made in an aircraft of the same category, class, and type (if a type rating is required), or in an approved training center simulator adjusted to simulate night.
The opportunity to operate special VFR under FAR 91.157 — that is, with lower than basic VFR weather minimums — is more restrictive at night. The term "night" does not appear in this regulation. Rather, it is implied because according to the regulation special VFR operations may only be conducted "between sunrise and sunset" — unless the flight meets other criteria. So, essentially it is a nighttime restriction, night being implicitly defined as the time other than "between sunrise and sunset." Unless the operation is between sunrise and sunset, a special VFR operation may not be conducted unless the aircraft is equipped for IFR flight and the pilot is IFR rated and current. During daytime special VFR operations, these IFR restrictions do not apply. The IFR restrictions do not apply to helicopters. In Alaska, the IFR restrictions apply unless the operation is when the sun is six degrees or more above the horizon.
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