Undercarriage out mid-flight

[JohnnyRocket]

I'm not a pilot, but I'm just looking for a rational explanation and this forums seems like the place to ask so hope you can help.

I was travelling yesterday on a Bmi flight from London Heathrow.... It was a clean evening, takeoff was fine - but about three to four minutes after takeoff soon after we had left the airfield, the engine noise quietened and we starting to slow down.

The undercarriage was put down again.... And then taken back up!

Now, in about 160 flights i've been on that's never happened!

I know that this sounds silly too, but I felt absolutely sick with worry! I didn’t know what was going on - and really , it is the last thing you expect especially whilst you're still taking off....

Added to this the airconditioning was blowing faster and slower whilst this was going on.

So - please, can anyone shed any light on why a pilot might carry out a procedure such as this - and is it dangerous at all?

[catchup]

If it was a A320/family maybe hot brakes or a false warning of that.

regards

[Rwy in Sight]

Thanks for the last comment regarding hot breaks and hyd leak. Something worrying crossed my mind...

About hyd leak and hot breaks. Aren't hyd fluids non-flamable? If yes how could be a fire hazard, and if not why not?

[Dr Illitout]

Skydrol is SUPPOSED to fire proof but any atomized liquid in my opinion should be treated as "dodgy". Also if there was a brake fire lets have it as far away from the plane as possible!!!
Rgds Dr.I.

[JohnnyRocket]

Hi there... Thanks for everyones responses so far. I didnt realise that the wheels heated up over the takeoff distance.

For your info it was an Fokker 100 aircraft from Bmi.

The reason i asked if it was dangerous is because i thought there was a maximum speed by which wheels had to be in by... and after a few minutes one would have though you'd be close to reaching that speed... thereby too fast to lower the gear once more?

[OzExpat]

In your initial post, JR, you said...
the engine noise quietened and we starting to slow down
So I guess the crew reckoned they needed to keep the speed back for the undercarriage extension/retraction exercise. That would be a normal precaution.

[Fil]

Sounds so much like the common hot brakes issue.

LHR can get so busy that on touch down the a/c behind may have crept inside 2.5 miles, and only at 600 ft....so you often need to brake hard to clear otherwise a go-around is required.

This leaves your brakes very hot, bearing in mind that the previous sector oculd have been only 30 mins from Manchester so they would not have been able to cool. Turn arounds are short these days so brakes still warm when departing. Taxi-ing the now heavy (fuel loaded) aircraft will add even more heat to the brakes.

Possible the brake fans were U/S and the crew took off with the brakes just inside limits but the temp was rising and a few mins after take-off got the hot brakes warning.

Best thing to do is jsut what you observed, slow down (<250kts on 319/320/321) drop the gear the let the brakes cool. The big Gotya being the raising limit is only 220 kts so perhaps they slowed right down to that speed early on.

[Old Smokey]

Any or all of the above responses may be the correct one. In my experience on several types, a gear door will indicate not properly closed (usually a microswitch), which necessitates reducing thrust, slowing down to gear operating speed, lower the gear fully, and attempt a further retraction. I guess 5 or 6 times over my career I've had to do this, it was always successful, and always a sticky or slightly uncooperative door position sensing microswitch.

[GlueBall]

Hey, JohnnyRocket, to ease your concerns on your next flight: Avoid being seated over the wing/wheel-well section. That way, if a tire explodes you'll live to tell about it. There are a number of recorded accidents where pax have been killed from exploding tires in the wheel-well. Sometimes "fuse plugs" don't work, and a hot brake could cause the tire to explode. "Fuse plugs" are designed to melt from from excessive heat and deflate the tire before it explodes. :{

[The Greaser]

Glueball, i think you have a future doing courses for those scared of flying!!

[Xeque]

Hey Glueball - ease up! Johnny Rocket had a very legitimate question that needed to be answered fairly by the experts who use this forum.

I thought he reported what he heard and felt very accurately. Certainly accurate enough for others to recognise exactly what had happened and to explain it.

Johnny Rocket, I hope you go on to enjoy many more journeys with airlines, whichever, wherever they are. And yes, take an active interest in what is happening around you. It adds to the fun of flying (and easing the pain of economy class seat pitch too!:O )

[Gerard123]

The heat in brakes can take up to 30 mins to show up. If the plane was turned around in 30 mins the ground crew would obviously not have had a chance to cool them down. The crew probably only got a warning after putting the gear up because they would've started heating up again now that they aren't in the airflow. Logic says put them out to cool, so thats obviously what they did. :ok:

[Old Smokey]

A lot of wise and correct responses here regarding the benefits of in-flight brake cooling. Even very hot brakes cool down in a remarkably short time, even just 1 to 2 minutes, but not a few seconds, which would seem to be implied in the original post -

The undercarriage was put down again.... And then taken back up!

In other words a gear cycle. My money's still on an incorrect gear/Gear Door UP indication which cleared after the cycle.

Whichever is the case, the Captain is guilty of poor passenger relations management, it is always the 'done thing' that an informative PA is made in the event of any odd-ball situation so noticeable to the passengers.

[Curious Pax]

Had a similar experience may years ago a couple of minutes after departure from LHR on a BA 737-400. Captain came on the PA, apologised for the noise and openly said that he'd pulled the wrong lever! Having read some of the responses here I do wonder if he thought that admitting to retracting the gear with red hot brakes might worry the pax more, but if that was the case I think I would prefer that to the implication that the Captain was given to pulling levers at random!

[WindSheer]

There is always one glueball - on every single post of this web site.:mad:

Surely JohnnyRocket deserves an apology does he not?
Dear oh dear!:E

[Captain Stable]

I tend to concur.

glueball, since your post contained quite a bit of information, I have refrained from editing or deleting it. But it could have been more tactfully and politely put.:cool: