On a typical weekday, there are 5,000 planes in the sky under instrument flight rules.
If the government decided to require airplanes to fly under instrument rules, that would overwhelm the aviation administration, experts said.
Originally, Mr. Black said, the Navajo's pilot had filed a flight plan to fly to Patuxent under instrument flight rules.
Nearly all the planes that are tracked, including all scheduled airliners, fly under instrument flight rules that require the planes to broadcast an identity number over their radios.
Usually, helicopter pilots, along with those in small planes, do not have to file flight plans, unless they are flying under instrument conditions.
He said only 30percentt of the 35 million flights a year occurred under instrument flight rules, guided by traffic controllers and radar.
Within airspace regulated by the F.A.A., large commercial aircraft as well as many general aviation airplanes have to operate under Instrument Flight Rules.
At Republic, the Island's only airport within the 20-mile ring around Kennedy, limited operations under instrument flight rules as well as flight instruction were able to resume Oct. 6.
Larger commercial airports, on the other hand, must also operate in the hours of darkness and under instrument meteorological conditions (IMC), when horizontal visibility is 600 metres (2,000 feet) or less and the cloud base (or "decision height") is 60 metres (200 feet) or lower.
The samples were tested under instrumented falling weight impact loading and compared with conventionally cured ones.
On Thursday, Brin joked that maybe Google Glass would one day allow for skydivers to fly under instrument flying conditions, where pilots can fly in the clouds.
