Turn at 400' AGL?

[CitationLover]

the 1500' agl is obviously a reference to smaller airports (thus the cessna reference). at ORD or DCA you will have a DP to follow, but not at GCK.

no turns below 400' agl is fairly standard. most of our emergency performance data is a turn at 1000' agl.


fly: how's coex?

 

[KingAirDriver]

As a general rule of thumb for our operations.....if there is no DP we climb to Circling Minimums for the approach to that runway and then make our first turn. Your Guaranteed Obstacle clearance at that altitude!

 

[avbug]

Only within the circling radius for the approach category to which your departure and climb speed correlates. Step outside that radius, and you have no promise.

Be sure that if you used category B minimums due to approach speed, but fly at Category D speeds on departure, you're referencing the Category D circling MDA when you use that rule of thumb...and remember that in that case, you're only good to a distance of 2.3 miles. Also bear in mind that airport restrictions may preclude maneuvering over a portion of the field, or the surrouding environment when circling...simply using a circling minimum is no gaurantee of surrounding terrain separation in all cases.

 

[Donsa320]

400 ft turns

The magic 400ft number pops up in 2 places.

One is; 400ft agl is the lowest altitude that can be used in Terps when designing a DP which involves a turn. A turning DP cannot require a turn below 400ft agl.

The other is; 400ft agl is the lowest EOAA (engine out acceleration altitude, formerly MGLO) that a manufacturer can establish. The constraints on EOAA altitude are usually the maximum power or thrust time limit on the engine(s) and obstacles. The lower you set EOAA the more obstacles become a factor and the higher you set it the closer to exceeding Max power/thrust time limits. It is a balancing act when certifying Transport Category airplanes.

Both of the above frequently are higher, but never lower.

Absent the above conditions then 400ft agl has no meaning . But if it is in your ops specs or FOM or comfort level or whatever, then of course abide by that. <grin>
D.C.and standing by for incoming.

 

[satpak77]

Unless using an instrument or obstacle departure procedure, you are technically supposed to follow this, according to a local POI who said he would start violating people for not complying with it.

I would like to see him try that. He is going to "violate someone" based on their violation of what reg? What? The AIM?

Where is he getting the data to build his case? Radar altitude? ATC tapes? Cessna ABC turned at 600 feet instead of 400 feet? Please

Yeah right. AOPA Legal/ALPA Legal would have a field day with that one.

AIM recommends 45 degree entry to downwind at uncontrolled fields but we know that doesn't happen everywhere. He11, there have been published articles in aviation magazines teaching "how to make straight ins at non-controlled fields safe" (!!!). Nobody being violated there.

Online Ops Inspectors please post your feedback

** by the way, the things you are "technically supposed to...." adhere to are technically addressed in the FAR's and (like you said) printed DP/SID/STAR procedures. If not, in most cases you are encouraged or recommended to follow or at least you should be aware of it. Examples are numerous (45 degree entry example above, TRW avoidance distance, wake turbulence avoidance, etc etc)

later

 

[avbug]

The magic 400ft number pops up in 2 places.

Three, actually. It's also a NBAA recommendation.

 

[A Squared]

Absent the above conditions (turning DP and min EOAA) then 400ft agl has no meaning .

No. that is not true, the 400' does figure into a diverse departure. If you look at the obstruction clearance zones in the TERPS, you will see that even a diverse departure is predicated on a climb on runway heading to 400', then a turn in any direction. In a departure analysis, the only area which is analyzed fro obstacles below 400' AGL is "zone 1" which extends out 2 miles on the runway centerline (and splays 15 degrees either side of centerline) from there, Zone 2 and 3 cover a turn in any direction. BUT, zone 2 and 3 obstruction clearence *begins* at 400' AGL. It would be entirely possible to have a 300' obstacle just outside zone 1 and underneath zone 3, whch you would hit if you made a 90 degree turn in a slow climbing aircraft before reaching 400' agl, yet the airport would still meet the TERPS criteria for a diverse departure.

This doesn't adress the question of whether a turn before 400' is permissible in VFR under 121, but once you have worked through the departure criteria in the TERPS it is very clear that a turn before 400' in IMC may put you in very close proximity to an obstruction.

In a fast climbing aircraft, you will *probably* be through 400' before you exit ZOne 1, so you'll *probably* be OK. In a slow climbing aircraft, you just might be clipping cell phone towers

 

[80/20]

I undersand the question to be about radar departures with initial heading to be flown immediately after takeoff. Just like the TERPS, FAA order 8260.19, (Flight Procedures and Airspace) establishes guidelines for IFR departure turning procedures which assumes a climb to 400 feet above the airport elevation before a turn is commenced. A premature turn should be a concern for obstacles, a very delayed turn might cause a separation problem. Don’t think we have a strict rule for this. FAA order 7110.65 (AIR TRAFFIC CONTROL) instruct controllers to consider known aircraft performance characteristics when applying separation to departing aircraft.

My personal view: Turn at 400 AGL if possible, would not get an ulcer if we blasted through 1000’ before we got our turn started. Technically you are right dreamguy and your capt. is “wrong”. Would I start an argument with the captain about this? – no, but I would try to discuss it in a constructive manner at a suitable time. Efficient CRM require both good leadership and good followership. Don’t be too eager to outshine your master but be assertive when safety is at risk.

 

[Donsa320]

A Squared

Hey, good catch, I cannot argue that point as my Terps manual is missing page 113. (Never lend manuals out). I see you are in DC-6's and I'll bet you are accutely aware of take-off obstacle clearance. <grin> Thanks.

D.C.

 

[Prop Trash]

Turns after takeoff may be commenced at 100' AGL in VMC at my company. In IMC, turns are permitted at 400' AGL or whatever the obstacle DP says. ExpressJet pilots, correct me if I'm wrong.