Filing IFR direct

7 Answers

1. 
   

   
   

   Pete Kemble on Oct 02, 2010

   As for increasing the workload of ATC, i’m not sure how that would be the case. If you’re concerned you can add SYLVR to the route allowing you to still stay mostly clear of KDEN, and it only adds +6nm to the trip. in my experience, ATC will start vectoring you pretty far out anyway – they might just give you an initial vector that takes you direct to the IAF – that keeps you mostly out of their hair, and will match the direct route on your flight plan for the most part. my experience has been between NY and boston, so take that into account too. For more info on direct routing, check the instrument procedures handbook, 3-26 – 3-31 or so.

   as for the altitude to file, the OROCA is the MINIMUM altitude you’ll want to be at – why not file a few thousand above that? ATC has their own set of altitudes, MVAs (minimum vectoring altitudes) that they might assign you, but for planning purposes, give yourself a nice cushion.

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   Matthew Waugh on Oct 03, 2010

   There is some dispute about whether filing (or even being given direct by ATC) increases ATC workload. As best as I can recall the arguments go a little like this.
   1. If the system won’t let you fly direct then you’re flight plan will get “fixed” to a non-direct route – that means when you call for your clearance you cannot be “cleared direct” but need a full route reading.
   2. Direct routes can intercept airspace you can’t enter, and the controller has to analyse whether that will be the case and re-route you, whereas if you were on a route, generally speaking, the controller would easily know if you were going to enter airspace you weren’t supposed to be in.
   3. One controller may clear you direct, but a controller further down the line needs you on a route, so it’s more work for ATC putting you back on a route later on as opposed to just leaving you on a route in the first place.
   If you want to hear the full rant check-in with Don Brown at http://gettheflick.blogspot.com/ – he’s a retired controller out of Atlanta.
   I think it’s less of a deal for low-level, slow-moving, GA traffic, but what do I know.
   File the altitude you want (which should be a legal altitude both for separation and obstacle clearance) and ATC will give you the altitude you can have. If you want a low altitude remember that, in radar contact, they have minimum vector altitudes (MVA) that are often lower than the OROCA – just ask.

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   Matthew Beyer on Oct 03, 2010

   Thanks for the answers. I actually filed and flew this yesterday and it went as expected. I filed direct, clearance was different than direct, and what I flew was also different. I chatted with them and it didnt seem to be an inconvenience as I had been warned before. Yes I could have gone to a point like SYLVR, but I was more using this to learn (not specifically to be fastest route). They gave me altitudes that were lower than OROCA and all was good. I had also discussed with the briefer as to what his system would take, seemed like it would take anything and any altitude (even lower than OROCA or MEA’s nearby). It further reminded me of the lesson from my CFI a while back, what you file will most likely be different than the clearance and even different to what they have you do. Thanks for the added info.

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   Kent Shook on Oct 04, 2010

   Matthew,

   Be careful about ever being below the proper minimum IFR altitude – If you’re on vectors, the controller should have you above their Minimum Vectoring Altitude, but we as pilots unfortunately don’t have any reference for where that is. In addition, if you’re not on vectors, for example “climb and maintain 7,000, cleared direct XYZ” it is YOUR responsibility, not ATC’s, to keep you at the correct (safe) altitude. If 7,000 is lower than the OROCA on your direct route, you need to say “Unable 7,000, request 9,000” or whatever is appropriate.

   Whether you get cleared direct or routed some other way also depends greatly on where you are and where your route will take you. Where I am, any time I go east, Chicago gets in the way so I’ll get cleared through KELSI intersection normally. These days, I just file KELSI when I’m headed that direction and I get “cleared as filed” 90% of the time, and the only reroute I get is Chicago Center clearing me direct destination as soon as I won’t run into Chicago Approach airspace.

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   Curtis Ide on Oct 04, 2010

   Wanted to mention a great website – http://www.fltplan.com 
   They give you the last 5 filed and last 5 actual cleared routes.  Since I have been using this I get As Filed a lot more than in the past especially when in unfamiliar areas.  Also a great tool for weather and filing flight plans.
   Good Accident study on expecting ATC to correct your altitude. 
   NTSB Identification: SEA08FA02314 CFR Part 91: General AviationAccident occurred Thursday, November 08, 2007 in Las Vegas, NVProbable Cause Approval Date: 11/10/2008Aircraft: CESSNA T182T, registration: N881CPInjuries: 2 Fatal.
   “THIS CASE WAS MODIFIED JANUARY 27, 2009.” The airplane collided with rising mountainous terrain during climb to cruise about 21 nm southwest of the departure airport. The accident occurred during dark night, visual meteorological conditions, about 13 minutes into the night cross-country flight. No lighted roads or round structures were present in the area to provide ground reference to terrain. 1% of the moons disk was illuminated. Over the last 6 minutes of the flight, recorded radar data indicated the airplane’s average groundspeed was 100 knots and its average rate of climb was 406 fpm; an average rate of climb of 600 fpm was required to clear terrain along the flight path. An examination of the accident site indicated that the airplane impacted rapidly rising terrain in a near level flight attitude before descending and coming to rest in a rock outcropping. The resultant high-energy impact forces, coupled with the extensive thermal damage, destroyed the airplane. A postaccident examination of the airframe’s structure and engine failed to reveal any preimpact failures or malfunctions. The airplane was equipped with a Garmin G1000 Integrated Cockpit System, which incorporates a multifunction color display that is capable of displaying terrain elevation information when selected to the Terrain Proximity page. Due to the extensive impact and thermal damage that the component had sustained, it was not possible to determine if the pilot was using the display to receive topographic data during the airplane’s ascent. Records indicate that the pilot had received G1000 training. The Pilot’s Guide for the G1000 states: “CAUTION: Use of Terrain Proximity information for primary terrain avoidance is prohibited. The Terrain Proximity Map is intended only to enhance situational awareness. It is the pilot’s responsibility to provide terrain avoidance at all times.” The flight was departing on a VFR flight plan and was receiving VFR flight following services from the Las Vegas Terminal Radar Approach Control facility. Air traffic control radar data revealed that the airplane was continuously visible to the controller on his radar display from the departure airport until impact with mountainous terrain. The airplane’s course remained constant as he approached and impacted the mountain during the dark nighttime flight. The air traffic controller did not issue a terrain-related safety alert, as required by a Federal Aviation Administration order, because he did not observe a conflict with terrain.
   The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
   The pilot’s failure to maintain an adequate terrain clearance/altitude during climb to cruise. Contributing to the accident were rising mountainous terrain, the dark nighttime lighting condition, the pilot’s loss of situational awareness, and the Federal Aviation Administration controller’s failure to issue a terrain-related safety alert.

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   Chris Findley on Oct 05, 2010

   I’ve had no real issues filing GPS direct.  But it also depends on where you are going and how your routing fits into the overall flow of things for ATC.  There is sometimes no great, convenient route so direct makes sense.   I’ve also filed, been cleared direct, and then recieved odd vectoring (from my perspective anyway) to a fix in the vicinity of the destination and then on in for the approach.  If there’s a convenient routing via airways, I’d take it.  If not, I wouldn’t hesitate to ask for direct.  You may not get it, but why not ask? 
   I agree with the concerns about alitude. Give yourself ample room above the OROCA and carefully check the route for terrain and other obstacles.

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   Matthew Beyer on Oct 06, 2010

   Thanks for all the insight. Just wanted to mention that my intent was not to try and always file direct just because I have /g equipment, it was for special cases like the one I mentioned from BJC to SNY. I know this route well and didn’t mind trying the direct IFR route for the learning. Here are my take-aways from the answers above as well as from my conversations with ATC when I did this last weekend:
   –          It is not directly an additional burden for ATC to receive a ‘direct’ route request. It can be used at appropriate times. Pete’s reference to IPH book above was a good help too.
   –          Be expected to NOT actually fly it direct even when filed or cleared as such. Reminds me of my CFI telling me there are 3 flight plans that are all different, the one you file, the one you are cleared for, the one ATC has you fly.
   –          Additional note, don’t simply plan fuel based on direct since it’s the best case route and not likely to be the actual route. Same for altitudes, the system may take my 8000 request but I may be sent higher, need to plan for this.
   –          Be well aware of all altitudes and do not rely on ATC as primary terrain and obstruction alerts. Side note to this. When I flew it on the return they cleared me to 8000ft. It took 23NM before I was on Denver Center Radar. So if I had filed higher, I would have had radio and radar closer which is handy in the real clouds. So picking higher altitude has many advantages as all stated from the thread.

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