Taxiway marking obstruction clearance expectations?

[chemgeek]

I'm hoping someone here can point me to the correct documentation to make a recommendation to our airport management.

Background: We had taxi markings (yellow centerline stripe) to assist a private owner to taxi a turbine aircraft from the ramp to his personal hangar. The personal hangar is in the opposite direction from the runway and taxiways and proceeds under a set of existing high tension lines and (previously) an overhead wire from a power pole to the maintenance hangar. These wires are not a factor for taxiing aircraft.

Incident: An intinterant helicopter attempted to follow the taxi markings from the ramp to air taxi and take off, aborting takeoff when noticing the wires. Subsequently, the airport management removed all the taxi lines from the ramp and those leading to the private hangar, and the (unused) overhead wire from the pole to the hangar.

Question: What are the expectations for helicopter takeoff operations (I'm not a helo pilot), and are there specific obstruction clearance expectations for helicopters following taxi markings? The AIM and PHAK are not specifically helpful, but the NBAA best practices document recommends air-taxiing toward the runway for takeoff operations. The helo pilot in questions suggested that the taxiway line guaranteed obstruction clearance for air-taxi and takeoff. (Doesn't sound right to me, but then again I don't fly helos.)

Second question: What kind of markings (if any) would be appropriate to provide taxi guidance for the private hangar owner without suggesting this is a usable taxi and takeoff area?

Hopefully, someone here actually knows the TERPS or whatever regs are relevant.

 

[RussR]

There are no TERPS here because those only deal with taking off from an actual runway or helipad. Takeoffs from taxiways and parking aprons are at the helicopter pilot's own risk. In fact, at a towered field, the controller won't even clear the helicopter for takeoff, rather specifying that it will be at their own risk.

That said, I don't think I've ever been at an airport where you taxied under anything - wire or otherwise*. Having wires strung overhead anywhere at an airport seems like a really bad idea.

* An overhead shade at an FBO like at DAL being the one exception.

 

[chemgeek]

There are no TERPS here because those only deal with taking off from an actual runway or helipad. Takeoffs from taxiways and parking aprons are at the helicopter pilot's own risk. In fact, at a towered field, the controller won't even clear the helicopter for takeoff, rather specifying that it will be at their own risk.

That said, I don't think I've ever been at an airport where you taxied under anything - wire or otherwise*. Having wires strung overhead anywhere at an airport seems like a really bad idea.

* An overhead shade at an FBO like at DAL being the one exception.

A set of depicted high-tension wires parallel the runway on the east side of the airport away from the taxiways and runways. It's depicted on the airport chart supplement. The private hangar is on the other side of those wires and is no factor as an obstruction for aircraft on the ground. The only thing allowed on that side of the airport (airpark) by the FAA are air-related businesses and/or private hangars.

 

[Walboy]

That said, I don't think I've ever been at an airport where you taxied under anything - wire or otherwise*. Having wires strung overhead anywhere at an airport seems like a really bad idea.

* An overhead shade at an FBO like at DAL being the one exception.

Here's an example.

Taxiway R at KPHX goes under a Phoenix Light Rail bridge. Tall enough for Boeing and Airbus airplanes to taxi beneath.

 

[Lindberg]

A set of depicted high-tension wires parallel the runway on the east side of the airport away from the taxiways and runways. It's depicted on the airport chart supplement. The private hangar is on the other side of those wires and is no factor as an obstruction for aircraft on the ground. The only thing allowed on that side of the airport (airpark) by the FAA are air-related businesses and/or private hangars.

So what was the helicopter doing over there?

 

[MauleSkinner]

So what was the helicopter doing over there?

Following the wrong taxiway line because he couldn’t be bothered to look at a chart?

 

[RussR]

Here's an example.

Taxiway R at KPHX goes under a Phoenix Light Rail bridge. Tall enough for Boeing and Airbus airplanes to taxi beneath.

View attachment 131350

View attachment 131351

Cool! I definitely wasn't thinking "major airport" though. Obviously some actual study and analysis went into constructing that.

 

[RussR]

A set of depicted high-tension wires parallel the runway on the east side of the airport away from the taxiways and runways. It's depicted on the airport chart supplement. The private hangar is on the other side of those wires and is no factor as an obstruction for aircraft on the ground. The only thing allowed on that side of the airport (airpark) by the FAA are air-related businesses and/or private hangars.

Is this the private hangar and wires you're talking about? Yeah, that is definitely an unusual layout.

Note I said it doesn't seem like a good idea (and it's not) - but that doesn't mean there's much you or the airport can do about it, short of the private owner paying to have the lines buried.

 

[Lndwarrior]

Paint "NO Helicopters" in large letters on the private ramp?

 

[RussR]

Paint "NO Helicopters" in large letters on the private ramp?

Not a bad idea. Although the helicopter in the OP's scenario was taking off (and I don't understand why the wires would be a problem for a helicopter taxiing from "the ramp" which is presumably the non-private parking ramp to the runway or taxiway), the problem I see here is for helicopters landing. That ramp outside of the private hangar sure looks like a pretty good landing area for a helicopter - not in the way of airplanes parking on the main ramp. But wires are notoriously hard to see from the air, and nobody would really expect to see them crossing what looks like an active taxiway. I can definitely see a hazard there. So I think some ground markings would be a great idea.

 

[Mikey52]

Or put balls on the wire.

 

[Capt. Geoffrey Thorpe]

Or put balls on the wire.

 

[chemgeek]

Is this the private hangar and wires you're talking about? Yeah, that is definitely an unusual layout.

Note I said it doesn't seem like a good idea (and it's not) - but that doesn't mean there's much you or the airport can do about it, short of the private owner paying to have the lines buried.

View attachment 131354

The medevac helicopter was (I think) getting fuel at the fuel farm. The wires are the a main transmission line for the area. It is depicted in the chart supplement. I'm trying to understand why a helicopter would elect to depart to the east (right) in the photo above. The markings to the hangar have been removed out of an abundance of caution, but I'm not sure they should have been a cause for the incident. When the military choppers fly in for fuel (we often get a flight of Cobras bound for Fort Drum) they taxi toward and depart from the runway.

 

[chemgeek]

Or put balls on the wire.

That was brought up at our last meeting. Unfortunately, they are not our wires, but a major transmission line. We will have to address that with the electric company that owns them. Meanwhile, a wireless telephone company wants to put a cell tower on a ridge directly underneath the downwind for 35, which will leave less than 500 feet clearance from the current pattern altitude. The FAA decided it was OK by them (?)

 

[chemgeek]

Paint "NO Helicopters" in large letters on the private ramp?

How about a permanent NOTAM or chart supplement entry specifically identifying the obstruction (wires) and prohibiting helicopter operations east of the ramp?

 

[Gilbert Buettner]

How about a permanent NOTAM or chart supplement entry specifically identifying the obstruction (wires) and prohibiting helicopter operations east of the ramp?

I, for one, do not have much faith in pilots checking NOTAMs.

 

[chemgeek]

I, for one, do not have much faith in pilots checking NOTAMs.

True that. Although with EFBs it's really easy.

 

[Lindberg]

That was brought up at our last meeting. Unfortunately, they are not our wires, but a major transmission line. We will have to address that with the electric company that owns them. Meanwhile, a wireless telephone company wants to put a cell tower on a ridge directly underneath the downwind for 35, which will leave less than 500 feet clearance from the current pattern altitude. The FAA decided it was OK by them (?)

I'd talk to the electric distributor and explain what's going on. They'd MUCH rather put balls on the wires than have to deal with someone hitting them.

 

[Lindberg]

Not a bad idea. Although the helicopter in the OP's scenario was taking off (and I don't understand why the wires would be a problem for a helicopter taxiing from "the ramp" which is presumably the non-private parking ramp to the runway or taxiway), the problem I see here is for helicopters landing. That ramp outside of the private hangar sure looks like a pretty good landing area for a helicopter - not in the way of airplanes parking on the main ramp. But wires are notoriously hard to see from the air, and nobody would really expect to see them crossing what looks like an active taxiway. I can definitely see a hazard there. So I think some ground markings would be a great idea.

He may have gotten turned around and thought he was heading towards the runway. Even without the wires, I wouldn't expect a helicopter to depart directly towards those hangars and perpendicular to traffic flow.

 

[Zeldman]

What kind of markings (if any) would be appropriate to provide taxi guidance for the private hangar owner without suggesting this is a usable taxi and takeoff area?

I was thinking to start, ''PRIVATE RAMP NO RUNWAY ACCESS''.

Or just park this close by...

 

[Clip4]

I'm hoping someone here can point me to the correct documentation to make a recommendation to our airport management.

Background: We had taxi markings (yellow centerline stripe) to assist a private owner to taxi a turbine aircraft from the ramp to his personal hangar. The personal hangar is in the opposite direction from the runway and taxiways and proceeds under a set of existing high tension lines and (previously) an overhead wire from a power pole to the maintenance hangar. These wires are not a factor for taxiing aircraft.

Incident: An intinterant helicopter attempted to follow the taxi markings from the ramp to air taxi and take off, aborting takeoff when noticing the wires. Subsequently, the airport management removed all the taxi lines from the ramp and those leading to the private hangar, and the (unused) overhead wire from the pole to the hangar.

Question: What are the expectations for helicopter takeoff operations (I'm not a helo pilot), and are there specific obstruction clearance expectations for helicopters following taxi markings? The AIM and PHAK are not specifically helpful, but the NBAA best practices document recommends air-taxiing toward the runway for takeoff operations. The helo pilot in questions suggested that the taxiway line guaranteed obstruction clearance for air-taxi and takeoff. (Doesn't sound right to me, but then again I don't fly helos.)

Second question: What kind of markings (if any) would be appropriate to provide taxi guidance for the private hangar owner without suggesting this is a usable taxi and takeoff area?

Hopefully, someone here actually knows the TERPS or whatever regs are relevant.

Taxiway markings are yellow.
General. All taxiways should have centerline markings and runway holding position markings whenever they intersect a runway. Taxiway edge markings are present whenever there is a need to separate the taxiway from a pavement that is not intended for aircraft use or to delineate the edge of the taxiway. Taxiways may also have shoulder markings and holding position markings for Instrument Landing System (ILS) critical areas and taxiway/taxiway intersection markings.

Since the surface you describe does not intersect a runway and is not for transient use, it should not have yellow centerline markings. If you want a centerline, paint it red and use a taxiway end marking at the entrance from the ramp.

 

[kkoran]

Taxiway markings are yellow.
General. All taxiways should have centerline markings and runway holding position markings whenever they intersect a runway. Taxiway edge markings are present whenever there is a need to separate the taxiway from a pavement that is not intended for aircraft use or to delineate the edge of the taxiway. Taxiways may also have shoulder markings and holding position markings for Instrument Landing System (ILS) critical areas and taxiway/taxiway intersection markings.

Since the surface you describe does not intersect a runway and is not for transient use, it should not have yellow centerline markings. If you want a centerline, paint it red and use a taxiway end marking at the entrance from the ramp.

View attachment 131391

Taxiway markings dont have anything to do with whether it intersects a runway or isn't for transient use (( exception being enhanced centerline markings).

The subject taxiway may technically be a taxilane--no real difference other than the lateral obstruction clearance requirements. Same yellow markings.

This is one of the risks helicopter pilots take when taking off or landing from/to these sorts of locations.

 

[Mikey52]

You could also put some across the taxi lane under the power line and put min clearance dimensions just before that with "overhead lines above here.


Overhead lines
Min clearance 12 ft

 

[kyleb]

That was brought up at our last meeting. Unfortunately, they are not our wires, but a major transmission line. We will have to address that with the electric company that owns them. Meanwhile, a wireless telephone company wants to put a cell tower on a ridge directly underneath the downwind for 35, which will leave less than 500 feet clearance from the current pattern altitude. The FAA decided it was OK by them (?)

We have a tower AT pattern altitude on a hill directly on the 45 for 01 at VPC. Hasn’t collected anyone yet…