Welcome to Flightinfo.com

  • Register now and join the discussion
  • Friendliest aviation Ccmmunity on the web
  • Modern site for PC's, Phones, Tablets - no 3rd party apps required
  • Ask questions, help others, promote aviation
  • Share the passion for aviation
  • Invite everyone to Flightinfo.com and let's have fun

"Cleared to cruise"

Welcome to Flightinfo.com

  • Register now and join the discussion
  • Modern secure site, no 3rd party apps required
  • Invite your friends
  • Share the passion of aviation
  • Friendliest aviation community on the web

pilothouston123

Well-known member
Joined
Jan 11, 2005
Posts
245
Here's the deal...
You are 20 miles or so from your destination airport. 4,000 ft. airport elevation is 850. its a VFR airport(no approaches)
ATC says Cleared to cruise KXXX airport. How low can you go leagaly under IFR? You are already at the MVA for the area. The MSA on the sectional is 2400. If you are in the clouds how low can you go? Obviously if its good viz you can cancel IFR and got to 500 AGL.
 
I would think you'd have to wait until you start your final descent to land with the field in sight. Similar to being cleared for a visual at a controlled airport. You can't leave your last assigned altitude until on your final descent to land.
 
I would think you'd have to wait until you start your final descent to land with the field in sight. Similar to being cleared for a visual at a controlled airport. You can't leave your last assigned altitude until on your final descent to land.


??????????

I think you fail to understand the concept of a cruise clearance. A cruise clearance gives you permission to descend at your discretion and execute the approach of your choosing with no further communication from ATC. In this case the OP is talking about a visual approach.

The lowest altitude you can descend to is the lowest published IFR altitude. Disregard the sectional, you are IFR. If you are on an airway, the lowest altitude will be the lowest altitude published for the airway. If you are off-route, use the grid MORA from the enroute chart. Minimum vectoring altitudes may be lower but in order to take advantage of them you'll need to be assigned them from ATC, in radar contact. You can't descend to the minimum vectoring altitudes on your own.
 
I'm saying that you can't descend from your last assigned altitude on a cruise clearance until you're established on a portion of an approach of your choosing, in this case a visual. Therefore, you would have to wait until you get the field in sight and are ready to start your final descent for the runway, just as if you had been given the visual at a controlled airport. Did I miss something?
 
Here's an excellent reference for this issue. The answer is it's up to the pilot to determine the minimum IFR altitude to fly unitl the airport. Take a look.

If the airport doesn't have a published approach, ATC isn't required to include a minimum altitude in the clearance. "Cruise 6,000 to the XYZ ranch" is all the pilot will probably hear. In this case, determining the applicable MIA is the pilot's responsibility. The Aeronautical Information Manual's pilot/controller glossary defines the MIA as the minimum altitude prescribed in Part 95 (airways and routes) or Part 97 (standard instrument approach procedures).

http://www.aopa.org/members/ftmag/article.cfm?article=2033

Learn something new every day if we're lucky.
 
Your link doesn't work for non aopa members.

To me, you don't have to have the destination airport in sight to descend under VFR. You have to be able to comply with 91.155. Let's say it is a hazy day and you are under the cloud layer, visibility is 3 miles. You don't have the field in sight, but you can descend in those VFR conditions and eventually execute a visual approach.
 
Here's more of the citation from the article:


If the airport doesn't have a published approach, ATC isn't required to include a minimum altitude in the clearance. "Cruise 6,000 to the XYZ ranch" is all the pilot will probably hear. In this case, determining the applicable MIA is the pilot's responsibility. The Aeronautical Information Manual's pilot/controller glossary defines the MIA as the minimum altitude prescribed in Part 95 (airways and routes) or Part 97 (standard instrument approach procedures).
These regulations apply only if a pilot is flying along an airway or an instrument approach. When he flys off these routes, a pilot reverts to Part 91.177(a)(2), which requires him to fly at least 2,000 feet above the highest obstacle within four nautical miles of his course in mountainous areas, and 1,000 above the highest obstruction within four miles in other areas. But how is a pilot supposed to determine obstacle clearance when he's flying off-route?
Until recently, IFR low-altitude enroute charts didn't provide off-route obstruction clearance altitudes (OROCAs). A pilot flying off-route had to determine his MIA using the maximum elevation figures (MEF) on a sectional chart. There was some question in many pilot's minds whether this was legal, but the FAA Certification Branch in Washington says it is-if the pilot uses a current sectional chart.
Let's plan a cruise clearance to the El Coyote Ranch airport, shown in Figure 1, which is part of the L-16 low altitude enroute chart. El Coyote Ranch is 42 miles north of McAllen, Texas and in a box defined by 26 and 27 degrees north latitude, and 98 and 99 degrees west longitude. The large 182 in this box is the OROCA. It's high because of the nearby radar balloon.
Obviously, getting an IFR cruise clearance at El Coyote Ranch is going to be useless unless a pilot uses the corresponding, current sectional chart. El Coyote itself is within by a smaller lat/long quadrangle, and its minimum safe altitude- 900 feet (09)-is a lot lower. This doesn't mean an IFR pilot can fly that low.
IFR chart MIAs include the 1,000- to 2,000-foot obstacle clearance buffers. Sectional chart MEFs don't do this. The pilot must add the appropriate buffer to the MEF. In this case, he couldn't cruise below 1,900 feet unless he's in visual conditions. If the pilot has any doubt about his ability to stay within the lat/long box, he must refuse the cruise clearance and go to another airport.
To increase safety, cruise clearances and MIAs should be part of a pilot's preflight planning because in flight it's easy to misread obstruction altitudes if you're distracted by turbulence, weather, and other IFR duties. Because a pilot must know before departure which destinations have instrument approaches, he has little excuse for not being prepared.
 
I would think you'd have to wait until you start your final descent to land with the field in sight. Similar to being cleared for a visual at a controlled airport. You can't leave your last assigned altitude until on your final descent to land.

Descent is at your discretion. I've been told to cruise FL450 before.
 

Latest resources

Back
Top