Tuesday, March 04, 2008

Know Your Friends

Should you ever find yourself in Point Reyes Station, pick up a copy of the local newspaper, the Point Reyes Light. One of my favorite parts of this paper is the Sheriff Calls which describes law enforcement activity for this rural community. It is written in such a ambiguous yet droll, Joe Friday, sort of way that it's often quite entertaining. Years ago, I read this item:
A man arrived home to find another man inside his house. When he asked the stranger who he was, the man replied "I'm one of your brother's friends." The man told the stranger "I know my brother's friends and you're not one of them." The other man left. When police arrived, they could not locate the man.
A pilot I fly with pointed me to the video below, I watched it and got that slightly sick feeling. An unintentional gear-up landing is a shame because the root cause is pilot error. Forgetting to put the gear down happens regularly and can be traced to several common causes, but like all accidents, gear-up landings are usually the result of a chain of events.

My intent is not to defame or ridicule the people shown in this video, but rather to learn from their mistakes. And the video illustrates at least three broken links in the safety chain: Failure to acknowledge the audible gear warning, failure to follow accepted checklist procedures, and failure to enforce a sterile cockpit during a critical phase of flight.

You can view the video here.

Virtually all aircraft with a retractable landing gear have some sort of gear warning system meant to prevent an unintentional gear-up landing. Gear warning systems typically associate certain aircraft configuration changes with the pilot's intention to land and if the gear handle is up, an audible (and sometimes a visual) warning is provided. Configurations that produce a gear warning usually involve reducing power below a certain threshold or configuring flaps beyond an approach setting while the gear handle is in the UP position.

If you routinely configure your aircraft such that the gear warning is activated, you are conditioning yourself to ignore the warning and this means good checklist procedures and cockpit discipline are the only thing between you and a gear-up landing. So one thing that pilots, instructors, and examiners can do is to avoid intentionally configuring the aircraft in a way that activates the gear warning. There are some training situations where the gear warning will be unavoidable, but that's not usually the case in day-to-day flight operations.

Many pilots who transition to a complex aircraft are not used to the aircraft's increased speed and the extra planning required when descending for an approach to landing. These pilots typically effect a descent by just yanking the throttle back, which activates the gear warning system. Do this on a regular basis and, well ... If you find you need to reduce the power such that the gear horn sounds, why not just consider extending the gear at that point to help the descent? Of course you need to be certain you are at or below the gear extension speed.

You can make routine work to your advantage by performing your Gear Down/Before Landing checklist in a consistent manner, thereby making it a habit. On a visual approach to landing in the traffic pattern, I encourage pilots to perform their Gear Down/Before Landing checklist when they are abeam their intended touchdown point on the downwind leg of the pattern, then again on the base leg of the pattern. Follow this up with a "Three Green and Stabilized" check at 400 feet AGL or so on final. If you are on an instrument approach, perform the Gear Down/Before Landing checklist at or just prior to the final approach fix, repeat it at 1000' AGL and follow it up with a "Three Green and Stabilized" check at 400 feet AGL or just before the minimum descent altitude.

Here's another thing that I find helps pilots verify the three green gear lights are illuminated - Keep your hand on the gear handle until the three green lights illuminate. Don't go any further in your checklist, don't do any other task, just keep your hand on the gear handle and wait. If there is an instructor, another pilot, or a passenger on board, use accepted cockpit resource management techniques by involving them in the process: When you have extended the gear, say to them "Three Green, no red lights, do you agree?" If you involve the front seat passenger or the other pilot or instructor in the process, you'll probably find it easier to enforce a sterile cockpit rule - no conversation that is not directly related to the flight.

Any time you get a gear warning, verbally announce it, especially if your aircraft has a mute switch that allows you to disable the audible warning. And if you know who your friends are - good habits, checklist discipline, and a sterile cockpit - you've made it highly unlikely that you'll ever land gear-up unintentionally.

8 comments:

Kevin said...

My instrument instructor taught me an excellent way not to forget. You initiate a descent /to the runway/ BY extending the gear.

This has the huge benefit of working when you're VFR or IFR, and it conditions you to begin the descent out of pattern altitude towards the runway by using the gear itself to add drag and begin that descent.

That has worked so well for my personal mindset that when I fly a fixed-gear airplane now, it causes a small hiccup in my mental progression of tasks when I prepare for landing when there isn't a gear switch or lever.

Very clever; worked for me. YMMV.

Kevin

John said...

Kevin,

I agree with your approach and would add that a GUMPS (Gas, Undercarriage, Mixture, Props, Seatbelt/Systems) check can be made work without a hiccup in a non-complex aircraft.

When you get to Undercarriage, just say "down and welded" (or "down and glued" if you're in a Cirrus). For Prop, just say "fixed". This lets you use a common procedure for fixed-gear and complex aircraft.

IFR Pilot said...

In 2MH, when making a VFR landing, my practice is:

Extend landing gear as I parallel the numbers of the opposing end of the runway. Check three green lights.

On base, check three green lights.

When I turn final and extend the last notch of flaps, check three green lights.

On short final, "Three in the green, mixture rich, prop set for go around." (This from watching Frank Holbert's videos on www.160knots.com)

I figure checking four times should ensure that I catch it at some point -- if the automatic gear extension system doesn't!

SloppyPilot said...

My inital instructor emphasised the down and welded part of the gumps check. It made he move to the retract more natural.

Although I'm still pretty fresh in the complex world and get that, "did I put the gear down?" panic response while I'm driving home from the airport.

Dave Starr said...

Excellent post, and some good comments too. Again, without meaning to cast aspersions on the guys who shared their video at all ... there but ... go I, I'd like to see more focus on stabilized approaches. The one leading up to this incident was anything but stabilized ... and way too far down the runway for my liking ... how long would they have landed had the gear been down?

John said...

David,

I agree that all pilots are capable of landing gear up and need to honor that fact.

As for the approach to landing shown in the video, I'm not sure what their goal was. Their target seemed to have been the 1000' marker and that's where they touched down (albeit with the gear up).

Aiming for the 1000' marker is not a bad technique, even though it's overkill in a small plane, and is often used when training pilots who plan to advance to commuter or transport category aircraft. I'm not sure I can judge the steepness of the approach based on a video taken from the back seat, but the end result certainly was unacceptable.

Ron said...

I am not a fan of lowering landing gear on downwind, or downwind abeam, or base because you don't always fly a downwind or base. Sometimes there's not much of a final either, making a tight 180 to get on the ground before wake turbulence from a parallel runway becomes a problem.

I've had to prepare people for 709 rides with the FAA because they failed to put the gear down, and when asked what their procedure was, they invariably say it was to lower the gear on downwind.

It's important to find something you do on every flight. What seems to work best, in my experience, is to lower the gear when you make your first radio call to the airport. Whether it's a CTAF or the tower, when you make that first call, put the gear down. Sure, it comes down earlier than if you lower it on downwind, but that's good -- the workload is much lighter at that point, which is a vital factor when flying single-pilot. You're usually on the way down anyway.

If you're the pattern, lower it as soon as you don't need to climb anymore.

Just my $0.02 on it.

I agree with you about being desensitized to the warning horn -- it really bothers me when people just let the horn blare on and on. The whole reason it's there is to prompt you to DO something. So condition yourself to make it stop.

John said...

Ron,

With all due respect, your argument that using one particular gear extension procedure is more likely to lead to gear-up landings and 709 rides seems dubious to me.

I certainly agree that destabilized approaches are problematic for a variety of reasons and the possibility of improperly configuring the aircraft is just one of the dangers.

I can think of a bunch of other situations where gear extension might need to be delayed - instrument approach with an iced-up airframe, a single-engine approach in a multi-engine aircraft to a high-density altitude airport. The list goes on and on.

Even Piper's attempt at implementing an automatic gear extension system created more problems than it solved.

Unfortunately, some pilots will continue to land gear-up. Aside from intelligently designed recurrent training for single-pilot operations, the only way to completely eradicate these accidents would be to leave the gear down all the time or fly fixed gear aircraft.

I don't have any silver bullets, other than emphasizing that one should not become immune to the gear horn and reminding all pilots that a gear-up landing could happen to them.