Door warning passing through 80 knots

[dasleben]

Alright guys, here's a situation I came across a few days back and thought I'd pose it to everyone. I'd like to see how many people handled it the same way I did. I won't say what I did yet, but I've been giving it a lot of thought and wanted some outside opinions.

Alright, here's the setup:

You're on a 7,000' runway with an accelerate/stop distance of right around 4000' on a dry surface. The current weather is 800/2 in moderate rain, and all runway surfaces are obviously wet (the performance charts do not address wet performance, only dry). The door warning system on the aircraft is MEL'd, with a previous writeup for the warning coming on in-flight with all doors secure. However, it's been your experience over the past two days of flying the aircraft that the warning system seems to work properly.

As you add power for takeoff, all warning lights are extinguished. Accelerating through 80 knots, however, the door warning illuminates (seen from behind the "inop" sticker), indicating that any one of four cabin doors may not be secure. That said, none of the doors have yet come open.

Do you:

Reject the takeoff?
Continue the takeoff and return to land?
Continue to your destination?
Other?

By the way, if it factors into some peoples' decisions, the aircraft in question is not equipped with a pressurization system. Filed cruising altitude is below 10,000'.

 

[wrxpilot]

At 80 knots, I'd reject with that much runway available. During maintenance testing with the mechanic at my old job, I did several rejected takeoffs at 80 kts with no issues (Piper Chieftain). The brakes are designed for it, and that's more than enough runway, even if it's wet (assuming a 1.5 factor for the moderate rain)...

I don't know the 402 that well, but there have been too many fatal accidents in Navajos due to the nose door blowing off into the left engine. Now if the runway was 5,000 ft, or you just rotated, that's a different story.

 

[dasleben]

I don't know the 402 that well, but there have been too many fatal accidents in Navajos due to the nose door blowing off into the left engine. Now if the runway was 5,000 ft, or you just rotated, that's a different story.

Something else I should mention is that the door warning light does not come on for a nose cargo door. Just the cabin doors, where there is no risk of having one blow off into an engine.

Thanks for the response so far.

 

[Cptnchia]

Something else I should mention is that the door warning light does not come on for a nose cargo door. Just the cabin doors, where there is no risk of having one blow off into an engine.

Thanks for the response so far.

If that's the case, I'd continue the takeoff, and just fly a closed pattern and land. If the doors open forward so that the slipstream will push them closed, and there is no danger of them getting ripped off, why not? Airplanes fly just fine with doors and windows open.

 

[Hacker15e]

What kind of airplane is it?

That makes all the difference as to if this is a "stop" emergency, or a "go" emergency.

Does the airplane have antiskid brakes? Is the runway grooved/textured for wet traction?

Also, what is the Refusal Speed? How close is 80 KIAS to that speed?

 

[Mike H]

Chop the throttles and stop on the remaining runway. No question about it. Even on a wet runway, you've got plenty of room to stop

 

[EatSleepFly]

As you add power for takeoff, all warning lights are extinguished. Accelerating through 80 knots, however, the door warning illuminates (seen from behind the "inop" sticker), indicating that any one of four cabin doors may not be secure. That said, none of the doors have yet come open.

Do you:

Reject the takeoff?
Continue the takeoff and return to land?
Continue to your destination?
Other?

I would absolutely continue the takeoff. In this case, and because the door warning system is MEL'ed anyways, has a history of "false alarms," and the doors appear secure, I would consider it legal and safe to continue to my destination and would do so.

If the system weren't MEL'ed, I would still continue the takeoff but whether I continued to my destination or not would first depend on what happened once airborne. If it's actually open, return for landing. Just a warning, it would depend on what the checklist says. Some checklists might say land as soon as practical, some might say keep the door area clear and continue. If there was no guidance for it or it wasn't contrary to the checklist, and I was sure the door was secure (I closed it myself, no noise, looks okay visually), I'd probably continue on to my destination.

Most airplanes can fly with open doors. All airplanes can fly with false door warnings. Aborts aren't something to take lightly, especially above 80 knots on a wet runway. There are only a very few things that I would want to abort for between 80 knots and V1 (or Vr I guess, in your case). In most airplanes I've flown, a door warning is not one of them.

 

[dasleben]

What kind of airplane is it?

That makes all the difference as to if this is a "stop" emergency, or a "go" emergency.

Does the airplane have antiskid brakes? Is the runway grooved/textured for wet traction?

Also, what is the Refusal Speed? How close is 80 KIAS to that speed?

This is a Cessna 402. No anti-skid brakes, and no published refusal speed. Vr was around 95 KIAS (actually, Vlof, but the difference between Vlof and Vr is negligible in this case), and company policy says no aborts post-80 knots unless it's an engine fire, failure, or loss of directional control. This came about after an overrun in EYW some years ago.

The runway is grooved.

Great responses everyone, thanks again!

 

[Polar742]

What was your plan for takeoff prior to leaving the blocks?

Did you consider the idea that the warning might come on during the roll? If so, what did you decide then?

 

[dasleben]

What was your plan for takeoff prior to leaving the blocks?

Pretty much what I said above. Below 80, abort for anything. Above 80, abort for engine failure, fire, loss of control. Company policy.

Did you consider the idea that the warning might come on during the roll? If so, what did you decide then?

Well that's no fun. This wouldn't be a very good thread if I just told everyone what I did.

 

[Hacker15e]

This is a Cessna 402. No anti-skid brakes, and no published refusal speed. Vr was around 95 KIAS (actually, Vlof, but the difference between Vlof and Vr is negligible in this case), and company policy says no aborts post-80 knots unless it's an engine fire, failure, or loss of directional control. This came about after an overrun in EYW some years ago.

The runway is grooved.

Not knowing the 402, how serious of an emergency is an open door in flight? Does it seriously change the flight characteristics? If the door is open *and* you have an engine failure, how does that change the single engine flight characteristics? Does it matter if it's the left engine or the right engine failed?

Sorry to ask so many questions, but an aborted takeoff (rejected takeoff in some vernaculars) can range from a non-event in some aircraft to a serious emergency that should only be executed under specific circumstances in other aircraft.

So, the answer to the question posed in the original post is highly dependent on these details.

My next question is....no refusal speed? So, you can abort the takeoff at any speed on any runway and stop in the remaining distance?? What am I missing here?

 

[MikeD]

not
my next question is....no refusal speed? So, you can abort the takeoff at any speed on any runway and stop in the remaining distance?? What am i missing here?

BAK-12

 

[ppragman]

Supposedly from the Servant Air Navajo crash the nose baggage door open blankets the tail. I dunno though, it depends primarily on the airplane. At ACE, we had annuciators in the 1900 that would get fish juice in them and flash during the takeoff roll. Nothing spookier than dual bleed air fail annunciators at exactly 80kts because some some fish goop slopped onto the printed circuit board.

 

[minitour]

In my plane, at 80 knots and a door light comes on I'm stopping. No question. That's a-cuz it could be the nose door and people die from that crap. If it's just the cabin door, I couldn't care less since it opens forward.

In a 402, with an MEL'd system I'd probably stop, go in, get mx and a new bird and be on my way.

-mini

 

[dasleben]

Not knowing the 402, how serious of an emergency is an open door in flight? Does it seriously change the flight characteristics? If the door is open *and* you have an engine failure, how does that change the single engine flight characteristics? Does it matter if it's the left engine or the right engine failed?

Couldn't tell ya! Depends on the door, of course, but there's no guidance in any manual about how a specific door affects single-engine characteristics. We naturally don't have a sim for such an airplane so there hasn't been a way to try it in a more controlled environment (though I doubt a sim would get it right anyway).

I will say this: I've had the upper part of the main cabin door come open at 180 KIAS and while it made a hell of a racket, it didn't do anything more than startle everyone. The airplane flew just like normal.

My next question is....no refusal speed? So, you can abort the takeoff at any speed on any runway and stop in the remaining distance?? What am I missing here?

I mean that there's no published V1. Normally our "take it in the air for anything" criteria is landing gear handle put into the "up" position. Once you've gotten to that point, you're committed to the takeoff. If you decide to put it back on the ground after rotation (there'd better be a damn good reason, i.e. you're on fire), it's your judgment call as to whether there's enough distance to stop the thing. For an accelerate-stop calculation only, it's predicated on the critical engine failing at liftoff speed.

 

[minitour]

I mean that there's no published V1. Normally our "take it in the air for anything" criteria is landing gear handle put into the "up" position. Once you've gotten to that point, you're committed to the takeoff. If you decide to put it back on the ground after rotation (there'd better be a damn good reason, i.e. you're on fire), it's your judgment call as to whether there's enough distance to stop the thing. For an accelerate-stop calculation only, it's predicated on the critical engine failing at liftoff speed.

Accel/stop + Landing distance? It won't be perfect, but it'll give you an idear.

-mini

 

[Mike H]

My next question is....no refusal speed? So, you can abort the takeoff at any speed on any runway and stop in the remaining distance?? What am I missing here?

From the information given, accelerate-stop of 4000' (accelerate to Vr and then come to a stop in 4000') on a 7000' runway still leaves 3000' extra runway to stop. Plus he was 15 knots less than Vr (95). From the information given, aborting the takeoff roll is the prudent decision, imo

Information not given, however was company policy of no aborts above 80 knots except for loss of directional control or engine failure, so continuing the takeoff is what's called for

Hey... I'm starting to think this was a trick question

 

[minitour]

Information not given, however was company policy of no aborts above 80 knots except for loss of directional control or engine failure, so continuing the takeoff is what's called for

Hey... I'm starting to think this was a trick question

Nah. Safety trumps "policy". Job be damned.

*edit*
Any place worthwhile isn't going to say boo about aborting below V1/decision point as long as you don't bend anything and have a valid reason ("a light came on" works for me). Cape is probably not going to say anything. Safe first.

-mini

 

[Mike H]

Well, there are some runways I wouldn't want to run off the end of even at 20 knots- or especially at 20 knots!

But it doesn't sound like this was one of those runways

 

[minitour]

Well, there are some runways I wouldn't want to run off the end of even at 20 knots- or especially at 20 knots!

But it doesn't sound like this was one of those runways

Accel/Stop says you aren't running off the end. Might blow a tire or make it square, but you're stopping.

-mini