Plane vs Tornado

[cdcollura]

Good day all,

I got a IM from this person (KB9VVP - www.skyodyssey.com) and figured I would share the story with you here ... A plane obvously is no match for both the shear and wind stresses with a tornado, whether aloft or near the ground!

KB9VVP: NLM Cityhopper Flight 431 was a short range passenger flight originating from Rotterdam Airport (RTM) in Rotterdam, South Holland, Netherlands, arriving at Eindhoven Airport (EIN) in Eindhoven, North Brabant, Netherlands, on the afternoon of Tuesday, 6 October 1981. Eindhoven was a stopover before final arrival at Hamburg Airport (HAM) in Hamburg, Germany.

The Fokker F28 Friendship 4000 took off at 5:04 pm CET (UTC +1). At 5:09 pm, the crew noted heavy rain in thunderstorms on the weather avoidance radar and received clearance to avoid the area. At 5:12 pm the aircraft entered a tornado whilst flying through clouds. The stress resulted in loads increasing to +6.8 G and -3.2 G. The right wing separated, there was partial in-flight breakup, and the aircraft crashed out of control from 3000 ft (900 m) near Moerdijk in the southwestern Netherlands. Flight 431 crashed 15 miles (24 km) south-southeast of Rotterdam, killing all aboard.

The disintegrating flight was seen exiting cloudcover. A police officer first photographed the tornado, then smoke from the burning plane a few minutes later. An investigation concluded that a sharp increase in altitude registered on the altimeter was not a change in altitude, rather a pressure drop associated with the tornado.

A report for this can be found at the URL below...

http://www.emairport.co.uk/disasters/100wo...st/19801984.htm

Or here's a snippet of the report from that site...

10/06/1981 17:12

LOCATION: Moerdijk, Netherlands
CARRIER: NLM (The Netherlands) FLIGHT: 431
AIRCRAFT: Fokker F-28 Friendship 4000
REGISTRY: PH-CHI S/N: 11141
ABOARD: 21 FATAL: 21 GROUND:
DETAILS: The aircraft entered an area of severe turbulence and a
tornado which resulted in the separation of the right wing and in-
flight break up.

Now, tornadoes, as most general public would NOT think, do not stop at the simple "base" of the thunderstorm, but do extend quite a ways up into the storm ... Especially in mescyclone induced tornadoes. Just see the two pictures below taken from June 12, 2005 in TX...

This (above) is the actual tornado on the ground, a wedge, with the cloud base above it. The clear RFD slot has not cut around it yet. In this picture, the tornado only appears to extend to the cloud base as per the casual observer...

What happened here (above), a few minutes later of the same tornado but with a wider view, is that the clear and drier RFD (Rear Flank Downdraft) has cut a large subsidence hole in the cloud updraft base (the view is looking north). Yes, sunlight is shining through this hole too! This allows the entire updraft "stack" of the tornado to be revealed, and visible up the RFD clear slot to almost 20,000 or even 30,000 feet!

Tornadoes like this often extend very far upwards into the clouds, whether or not it is visible to a surface oberver (or whether an RFD erodes enough clouds to actually see it - the tormado and / or parent mesocyclone "stack").

Who the heck would want to be unlucky enough to fly through a tornadic storm at ANY altitude?

It appears that the story about the plane crash and breakup was because the plane was vectored around the "core" of the storm by ATC, avoiding all the "hard" precipitation, but flew through the updraft, and unfortunately, also through the tornado core inside the cloud envelope.

FYI - I did provide a picture of a Fokker F-28 - Similar, but much smaller than an MD-80 / B717.

Chris Collura - KG4PJN

 

[Tim Vasquez]

Interesting... when I saw the subject line for this post this was the exact incident I was thinking of. I haven't seen anything that actually tied this with tornado damage and a tornado track (and would like to), but I do think that only a tornadic circulation could inflict that range of G-forces on a plane flying at relatively low airspeed.

A similar incident worth noting is the 8/6/66 breakup of a Braniff BAC-111 (slightly larger aircraft) south of Omaha. From what I recall the plane was penetrating at a very low altitude, like 5000 ft, into the front of a linear storm area (good altitude for catching a tornadic circulation). I can't find anything definitive about it on Google
http://www.google.com/search?hl=en&q=brani...G=Google+Search
but it's covered well in Macarthur Jobs' Air Disaster Vol 1.

Tim

 

[Mike Peregrine]

I've often wondered about just how much stress a plane would be able to withstand in these conditions. We saw a national guard plane fly under developing rotation one time and right through the RFD of a supercell in Missouri. He didn't seem to have any trouble, but I wondered just how much training the pilots have in being able to recognize cloud structure and avoid the most turbulent updrafts. I would think that since a plane is able to withstand airspeeds of hundreds of miles per hour, the problem comes more in shear and in vertical updraft - or wind hitting the plane from below (or possibly even from above in the case of RFD) - rather than from horizontal winds.

 

[Scott Olson]

Here's one more from an interview with Tom Grazilus:
Grazulis told me that from all his research, he could recall only one fatal aircraft accident involving a tornado. A tornado was nearby when a single-engine plane crashed south of Topeka, Kan., on Oct. 31, 1984, killing all three people on board. The tornado killed two people on the ground. The airplane was about 10 miles south of the Topeka airport, and probably about a mile from the tornado as the pilot talked by radio with to air traffic control

The T-28 (SD M&T) flew through hail, updrafts and even in mesocyclones.
Most commercial aircraft could be brought down by just one of the hazards though.

 

[Scott A. Kampas]

T'was I that sent that. Another good webpage is: http://aviation-safety.net/database/record...p?id=19811006-0 .

I first read about it in The Tornado: Nature's Ultimate Windstorm by Tom Grazulis.

Another source is: Roach, W.T., and J. Findalter (1983). "An Aircraft Encounter with a Tornado". The Meteorological Magazine 112 (February): 1327, pp 29-49.

Scott