Ask The Pilot

[jb747]

What damage to the hull (or engines) would you expect to have from such an impact.

It might be able to break a radome, or dent a leading edge. An engine in a biz jet probably wouldn't like it, but I'd expect a larger engine to survive, though perhaps with a bent blade or two.

Strange...as I was writing about bird strikes, my house had one...a bird flew into one of the windows. House won.

 

[AviatorInsight]

Thanks - I never realised the effect was so marked. There must be some airports around the world where that effect is quite strong, and the thrust on/off essential - how is that sort of knowledge disseminated - by each airline in its internal notes/manuals to its pilots or, if there is such a thing, an 'about this airport' put out by the airport concerned?

There's no such note or manual to tell us because every day is different and dependant on the conditions. Unfortunately it just comes with experience of flying into these places. Like JB mentioned, 34 into MEL, I also find it on 16 into MEL when the hills stop and you pass over the spotting area. In BNE coming into either 19 or 01 with an easterly and the winds are all of a sudden masked by the trees, so I'll usually do a flap 30 landing with anything more than 10kts in BNE.

 

[straitman]

Whilst it is unusual for these situations to cause major issues it is possible.

There have been several very embarrassed RAAF pilots flying Caribou over the years. Admittedly both were flying short field landing so the margins are minimised. One of these was at NAS Nowra and the other at Bulolo PNG resulting in both aircraft being written off.

 

[jb747]

Whilst it is unusual for these situations to cause major issues it is possible.

There have been several very embarrassed RAAF pilots flying Caribou over the years. Admittedly both were flying short field landing so the margins are minimised. One of these was at NAS Nowra and the other at Bulolo PNG resulting in both aircraft being written off.

Shortly after I joined QF, I flew with the bloke who'd been the FO on the Caribou event at Nowra. When the wind was from the right direction, there was major undershoot shear on 27. I think that by my time there, they had actually filled part of the valley in to reduce the shear near the threshold.

Supposedly the story was that the Caribou was demonstrating a short landing, got caught by the shear and landed extremely hard and short, punching the undercarriage up through the wings. ATC said that it was very impressive, and could they do it again.

 

[straitman]

ATC said that it was very impressive, and could they do it again.

That's embarrassing.

I had Canberra tower ask me that once when a student didn't flare on an autorotation which resulted in an 80kt running landing in a Iroquois. Also another time when the student did flare on a hovering autorotation which resulted in us bouncing and skidding on the nose with the main rotor blades about 6-12 inches from the ground. (Same student each time and I'm sure you know him JB)

 

[jb747]

Those students are sent to improve your instructional technique...

 

[straitman]

Those students are sent to improve your instructional technique...

... and in my case send me prematurely grey.

 

[juddles]

S... the Caribou was demonstrating a short landing.....

I only flew in a Caribou as a "pax" a couple of times - and at the time I was fresh out of intercontiental jets. To say I was disconcerted is an understatement. But i love the plane.

Back on topic, apart from the "cosmetic" damage that hail can do, is it a serious threat to modern commercial airliners? I understand JB's comments on its relative invisibility on weather radar. I am always amazed at the state of the planes that suffer it - because of the contrast between destroyed nose cones / windshields, and the apparently unscathed airframe, wings, engines. I am in awe of the engineering of modern engines - they ingest ice blocks whilst doing 890 kmh and come out unscathed??

 

[jb747]

Back on topic, apart from the "cosmetic" damage that hail can do, is it a serious threat to modern commercial airliners? I understand JB's comments on its relative invisibility on weather radar. I am always amazed at the state of the planes that suffer it - because of the contrast between destroyed nose cones / windshields, and the apparently unscathed airframe, wings, engines. I am in awe of the engineering of modern engines - they ingest ice blocks whilst doing 890 kmh and come out unscathed??

I'm not convinced that the engines are unscathed, and I'd love to see some images of the fans involved.

A quick search didn't find any engines that were hail damaged, but did find this sad example...
This Harrier flew into a hail storm • r/aviation

 

[jb747]

I'm sure you've experienced those flights where the seat belt sign comes on, and you don't get bumped around. After a while you think we've forgotten about the signs.

It might seem smooth down the back, but this is what we were looking at the other day. The signs were ultimately on for over an hour.

 

[jb747]

Our own lightning display. St Elmo's on the windscreens.

 

[Cynicor]

I'm sure you've experienced those flights where the seat belt sign comes on, and you don't get bumped around. After a while you think we've forgotten about the signs.

It might seem smooth down the back, but this is what we were looking at the other day. The signs were ultimately on for over an hour.

View attachment 129984View attachment 129985

That's really good to know JB, as sometimes you are busting for the bathroom and just wondering if the pilots are still aware of the sign. Interesting how it doesn't always translate to bad turbulence.

 

[MEL_Traveller]

Helicopter question. We have a hospital down the road with air-ambulance facilities. Sometimes when the helicopters depart the engines are started up and they depart almost immediately... maybe a minute or two in total from time of engine start-up. Other times the engines are started and the helicopter stays there, engines going, for 5, 6, 7 or 8 minutes before finally lifting off.

What explanation is there for the difference in departure times - weather doesn't seem to be an issue, and at 2 or 3 am in the morning I don't know if there'd be a lot of other traffic around?

 

[straitman]

Helicopter question. We have a hospital down the road with air-ambulance facilities. Sometimes when the helicopters depart the engines are started up and they depart almost immediately... maybe a minute or two in total from time of engine start-up. Other times the engines are started and the helicopter stays there, engines going, for 5, 6, 7 or 8 minutes before finally lifting off.

What explanation is there for the difference in departure times - weather doesn't seem to be an issue, and at 2 or 3 am in the morning I don't know if there'd be a lot of other traffic around?

Where are you MEL_Traveller?
(Just to help answer.)

 

[MEL_Traveller]

Where are you MEL_Traveller?
(Just to help answer.)

In Melbourne, the hospital is the Alfred.

 

[straitman]

In Melbourne, the hospital is the Alfred.

There are a variety of reasons but the most obvious is where is the aircraft going to and why. All ATC is prioritised with Med1 being the highest normal priority. If the helicopter is departing on a medical flight then ATC will move everything out of its way. If it’s returning to base or somewhere else then they have to wait there turn down the pecking order.

 

[MEL_Traveller]

If it’s returning to base or somewhere else then they have to wait there turn down the pecking order.

Ah, makes sense, although do they need to start their engines before seeking ATC clearance? During the day not much of a problem, but at 3am it has a fairly big impact.

 

[straitman]

Ah, makes sense, although do they need to start their engines before seeking ATC clearance? During the day not much of a problem, but at 3am it has a fairly big impact.

Unfortunately yes as there is no point in calling ATC until you are ready.

 

[MEL_Traveller]

Unfortunately yes as there is no point in calling ATC until you are ready.

Thanks for the reply. I thought (hoped) it might have been like aircraft where ATC can give a time slot in advance of pushing back from the terminal, and engines start after that.

 

[straitman]

Thanks for the reply. I thought (hoped) it might have been like aircraft where ATC can give a time slot in advance of pushing back from the terminal, and engines start after that.

I guess that could work in theory but having ‘been there, done that’ at the Alfred you never know when you are released until it actually happens.

The most efficient way then is to start up and call them.